Download D2.3 Indicators and protocol for assessing impact

ENHANCEMENTS OF PEST RISK ANALYSIS TECHNIQUES
D2.3 A set of written indicators and a written protocol
for scoring levels of impact in the EPPO PRA scheme
accessed via a hyperlink in a project web page
PD No. D2.3
Author(s): Johan Bremmer, Marc Kenis and Tarek Soliman
Partner(s): LEI, CABI, WU
Submission date: 26 July 2011
EU Framework 7 Research Project
Enhancements of Pest Risk
Analysis Techniques
(Grant Agreement No. 212459)
1
PRATIQUE
No. 212459
Deliverable number: D2.3
Date: 09/05/2017
_____________________________________________________________________
PROJECT OVERVIEW: PRATIQUE is an EC-funded 7th Framework research project
designed to address the major challenges for pest risk analysis (PRA) in Europe. It has three
principal objectives: (i) to assemble the datasets required to construct PRAs valid for the
whole of the EU, (ii) to conduct multi-disciplinary research that enhances the techniques used
in PRA and (iii) to provide a decision support scheme for PRA that is efficient and userfriendly. For further information please visit the project website or e-mail the project office
using the details provided below:
Email: [email protected]
Internet: www.pratiqueproject.eu
Authors of this report and contact details
Name: Johan Bremmer
Partner: LEI
E-mail: [email protected]
Name: Marc Kenis
Partner: CABI
E-mail: [email protected]
Name: Tarek Soliman
Partner: WU
E-mail: [email protected]
Disclaimer:
This publication has been funded under the small collaborative project PRATIQUE, an EU 7th
Framework Programme for Research, Technological Development and Demonstration
addressing theme: [kbbe-2007-1-2-03: development of more efficient risk analysis techniques
for pests and pathogens of phytosanitary concern call: fp7- kbbe-2007-1].
PRATIQUE
No. 212459
Deliverable number: D2.3
Date: 09/05/2017
_____________________________________________________________________
Table of Contents:
1
Introduction and objectives
2.1
Objectives.
2.2
Indicators
2.3
Scoring systems
2.4
Adjustments of the EPPO PRA scheme
3 Changes to the introduction of the assessment of potential economic
consequences
4 Questions, indicators and scoring systems for economic impacts
4.1
Introduction
4.2
Adjustments of the scheme
5 Indicators and scoring systems for social impacts
6 Indicators and scoring systems for environmental impacts
6.1 Introduction
6.2 Questions for plant pests
6.3 Questions for pest plants
7 Scoring systems for additional effects and conclusion
3
5
5
6
7
8
10
10
10
21
24
24
24
37
50
1
Introduction and objectives
Text in the DoW:
Task 2.3 Guidance for identifying indicators and scoring levels of
impact in the EPPO PRA scheme
To assess economic, environmental and social impacts, key indicators,
such as short-term costs for producers and traders, long-term loss of
competitiveness, indirect effects in related sectors, pollution of the
environment, vulnerability of receptors and loss of biodiversity can be
identified. We will determine the key indicators required for impact
assessment and develop a quantitative scoring system for these indicators
that can be related to the five levels of impact required for each question in
the EPPO PRA scheme. Where the level of impact is difficult to quantify,
qualitative values will be applied. The scores will be based on real world
examples of pest impacts and information acquired by the review
undertaken in task 2.1 and tested with case studies. The results will be
supplied
to WP3
(Subtask
3.1.2) where
guidance
on the not
scoring
To
undertake
impact
assessments
in PRAs,
the assessor
onlyof
needs tools
different
levels
of
risk
within
the
EPPO
PRA
scheme
is
being
coordinated
to assess the impacts quantitatively, but also guidance on the selection
of
and prospects
for the
mapping
areas
with greatest
impacts
will
be explored
indicators
to score
impacts
qualitatively
so they
can be
rated
according to
with
WP3
(Subtask 3.3.4).
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tasklevels
will beofundertaken
by CSL,
LEI,
the
five
(occasionally
more than
impact proposed
in CABI,
the EPPO
WU,scheme:
JKI and minimal,
Imperial.minor, moderate, major or massive. This is of great
PRA
importance for two reasons:
1. Consistency: it enables the risk assessor to apply the PRA scheme
correctly and consistently.
2. Transparency: it enhances the communication and common understanding
of pest risks. This is of great importance for regulators when deciding whether
phytosanitary measures should be taken, determining the strength of such
measures and responding to any challenges.
The objective of this report is to recommend indicators to associate with the
scores for each question in the impact section of the EPPO PRA scheme, and
to develop scoring systems. However, during the execution of this task, it
became apparent that the questions in the impact section including the notes
needed to be revised. Furthermore, the development of methods for
qualitative economic impact assessment and environmental impact
assessment (task 2.4) coincided with the revision of the impact section of the
PRA scheme. Therefore, these methods are also described in this report.
The report is structured as follows. In chapter 2 basic principles are explained.
In chapters 3, 4 and 5 each EPPO PRA scheme question on economic,
environmental and social impacts respectively is presented and indicators are
recommended for each impact score. Chapter 6 contains scoring systems for
additional effects. In chapter 7, the results are discussed and the
recommendations are summarized.
3
Note
The EPPO PRA scheme is currently revised. Suggestions for adjustments
arise during development of different tasks in PRATIQUE. Task 2.3 has a
major role in linking deliverables developed in WP2 to the scheme.
Therefore, this report is developed in cooperation with the EPPO PRA
panel in order to secure that the final deliverable fits to the revised
scheme.
4
2
Basic principles
2.1
Objectives.
The suggested indicators and scoring systems need criteria which can be
used to evaluate whether they contribute to the objectives as formulated in
chapter 1 (consistency and transparency). Furthermore the results of a PRA
must lead to clearly interpretable results, which can be used by policy makers
to decide whether phytosanitary measures should be applied. At the end of
the Pest Risk Assessment stage, the overall risk, composed from likelihood
and magnitude, each scored at a 5-point scale to show whether the risk is
very low, low, medium, high or very high must be obtained. Ideally, these
categories should have little overlap. The objective of this chapter is to
propose the criteria for indicators and scoring systems and to explore the
consequences for the EPPO PRA scheme.
2.2
Indicators
The EPPO PRA scheme provides a decision support scheme for the
International Standard for Phytosanitary Measures (ISPM) 11 developed by
the International Plant Protection Convention. To assess impacts qualitatively,
this deliverable provides indicators to enable assessors to judge consistently
which of the five scores should be selected when answering questions in the
EPPO PRA scheme. However, since many of the questions cover several
types of impact, we have developed indicators for the different types of
impact, which we call ‘input indicators’. Input indicator values are input in an
assessment module, which calculates the impact, expressed by an ‘output
indicator’. The output indicator value summarizes the total economic, social or
environmental impact.
The challenge is illustrated by looking at question 2.1 in the EPPO PRA
scheme (EPPO, 2009) available at the start of PRATIQUE:
How great a negative effect does the pest have on crop yield and/or quality to
cultivated plants or on control costs within its current area of distribution?
Note: Factors to consider are types, amount and frequency of damage
and crop losses in yield and quality, together with costs of treatment.
In this question, three types of economic impact are distinguished: yield loss,
quality loss and increase in production costs. We have investigated how each
type of impact can be provided with its own input indicator to ensure that it is
considered in sufficient detail. We have also explored how these separate
indicators can be combined in an output indicator (e.g. €) to give an overall 5
level risk rating, from minimal to massive, for each question.
Since ISPM 11 recommends the use of monetary terms, but allows qualitative
indicators, monetary terms have been used to express the impacts wherever
possible. To enhance decision making, it is recommended to use as few
indicators as possible to summarize all potential indicators. This point is
5
extensively discussed in the review of impact assessment modules (D2.1).
According to the recommendations of the review, monetary values will not be
used to express environmental and social impacts.
2.3
Scoring systems
One of the main objectives of the PRATIQUE-project in general and of this
task in particular is to enhance consistency in PRA production. This leads to
the following principles:
1. Scale dependency. Scoring systems can be formulated in absolute
terms and relative terms. If absolute indicators are applied, the
magnitude of the impact is expressed independent from the size of the
PRA area and the size of the affected industry. If relative indicators are
applied, impacts are assessed in relation to the maximal possible
impact, without using absolute terms. Impacts need to be expressed in
relative terms in the EPPO scheme so that the impact scale depends of
the size of the region and/ or the industry. However the maximum
possible impact depends on the size of the PRA area and the size of
the affected industry. When performing a quantitative impact
assessment, the size of the region and the size of the affected industry
have to be determined explicitly. Key data about:
- The specification of the product
- the size of the area suitable for establishment and
spread,
- the volume of the host plants, both in production
systems, in living areas and in natural environments,
- the production value and
- export volumes
have to be supplied in order to enhance interpretation of scores by
decision makers.
When performing a qualitative analysis, the final conclusion of the
impact assessment will have to embedded in estimates of key figures
indicating size and importance of the plants and products at risk.
2. Time dependency. Guidance should be given on how the pest risk
analyst should take time into account. In the case of assessing
magnitudes, it must be clear if the impacts are expressed in total for the
whole period until the time horizon or are expressed per year. It is
recommended to express the impacts per year when the impacts have
reached the maximum level.
When a qualitative impact assessment is conducted, there is no need
to take the time constraint into account. In the case of a quantitative
approach, it is recommended to present the economic impacts per year
and to conduct the economic impact assessment when the maximum
geographical distribution has been reached and at 5 years forward in
accordance with the assessment of spread. Another option is to
evaluate the impact for different scenarios where different proportions
6
of the area of potential establishment are considered to be invaded
(e.g. 10 %, 25%).
3. Order of magnitude. Impact categories differ from each other in order of
magnitude. This principle is based on logarithmic scales in the case
boundaries of impact categories are quantified (which is not applied in
the EPPO PRA scheme) and can determined by application of a fixed
multiplier.
4. Consistency. Scoring systems with similar indicators will be similar. If
yield reduction and change in production costs are both measured in
euros, than the scoring system will be similar.
2.4
Adjustments of the EPPO PRA scheme
Application of the basic principles to derive indicators and scoring systems,
and the application of impact assessment modules to calculate the impact
requires adjustment of the EPPO PRA scheme. The following reasons for
adjustment are used:
1. All questions regarding economic, environmental and social are
subsequently grouped together.
2. The questions are formulated in such a way that answers
provide the input for the impact assessment modules, whereas
the outputs of those modules will need to be related to the 5level scoring system.
Furthermore, in line with principle 1, it is recommended that consistent
categories are used for scoring risk (likelihood and impacts) and
uncertainty together with the written justification. It is therefore
recommended that the categories ‘impossible’ and ‘certain’ are deleted in
questions 2.10, 2.12, 2.14 and 2.15.
7
3
Changes to the introduction of the assessment of
potential economic consequences
In the PRA scheme, the section on impact assessment is preceded by an
introduction. This introduction needs to be adjusted for the following reasons:
1. Some basic principles have to be added.
2. This section needs some guidance when the use of the quantitative
module is recommended and when the qualitative method will suffice.
3. The numbering of the questions has to be adjusted.
Below, an adjusted introduction is presented.
The main purpose of this section is to determine whether the
introduction of the pest will have unacceptable economic
consequences. It may be possible to do this very simply, if sufficient
evidence is already available or the risk presented by the pest is widely
agreed. Start by answering Questions 6.01 – 6.11. If the responses to
question 6.04 and 6.05 are "major" or "massive" or any of the
responses to questions 6.06, 6.09, and 6.11 is “major" or "massive” the
evaluation of the other questions in this section may not be necessary
and you can go to 6.15 unless a detailed study is required or the
answers given to these questions have a high level of uncertainty. In
cases where the organism has already entered and is established in
part of the PRA area, responses to questions 6.01, 6.08 and 6.10,
which refer to impacts in its area of current distribution, should be
based on an assessment of current impacts in the PRA area in addition
to impacts elsewhere.
For the qualitative assessment of economic, environmental and social
impacts, detailed guidance is provided for every question to help the
risk assessor to rate the level of risk. A quantitative module is also
available for economic impact assessment1. The quantitative module is
appropriate for use in cases when
(a) at least moderate economic impacts are expected,
(b) these impacts cover a large area or affect different industries and
1
The quantitative economic impact module has not been fully evaluated by the EPPO PRA
Development Panel so this module is only directly linked to the PRATIQUE version of Capra
(for further explanation see PRATIQUE deliverable 6.5).
8
(c) sources (data, time and skills) are available to conduct a
quantitative analysis. Quantitative assessments are particularly likely to
be required where the level of impacts is unclear or the analysis is
required to justify measures. The key data necessary for a quantitative
analysis include:
 the specification of the product,
 the size of the area suitable for establishment and spread,
 the amount of the host plants, both in production systems (total
yield), in living areas and in natural environments,
 the production value and
 export volumes.
Expert judgement is used to provide an evaluation of the likely scale of
impact. Detailed guidance is provided for every question to help the risk
assessor to rate the level of risk. If precise economic evaluations are
available for certain pest/host plant combinations, it will be useful to
provide details.
The replies should take account of both short-term and long-term
effects of all aspects of agricultural, environmental and social impact.
When a qualitative impact assessment is conducted, there is no need
to take the time constraint into account. In the case of a quantitative
approach, it is recommended to present the economic impacts per year
and to conduct the economic impact assessment when the maximum
geographical distribution has been reached (see q. 6.04) and at 5 years
forward (see q. 6.05) Another option is to evaluate the impact for
different scenarios where different proportions of the area of potential
establishment are considered to be invaded (e.g. 10 %, 25%).
In any case, providing replies for all hosts (or all habitats) and all
situations may be laborious, and it is desirable to focus the assessment
as much as possible. The study of a single case may be sufficient, e.g.
if the effect on one host exceeds the effect on all other hosts together.
It may be appropriate to consider all hosts/habitats together in
answering the questions once, if effects on these hosts are
comparable. If a selection is made, it should be justified. Only in certain
circumstances will it be necessary to answer the questions separately
for specific hosts or habitats. This is the case if the majority of the
affected producers suffer minor or moderate impacts, but a small group
suffers major or massive impacts. Differences can be caused by
different host plants; differences between crops and amenity plants or
differences between cropping system: conventional and organic
production.
When the PRA is performed on a pest proposed for deregulation, the
current impact noted in the area may be linked to the implementation of
phytosanitary measures. The assessor should evaluate the possible
impact for a scenario where these measures targeting the pest are
withdrawn.
9
4
Questions, indicators and scoring systems for economic
impacts
4.1
Introduction
In this chapter, suggestions will be made to the questions regarding economic
impacts. The questions will be formulated in such a way that the answers are
input in the economic impact assessment module. The old questions
numbered with 2.x are followed by new questions numbered with 6.x. In the
case of a quantitative assessment, figures have to be given, in the case of a
qualitative approach, qualitative scores will suffice. Indicators, both qualitative
(option 1) and quantitative (option 2) are presented after the question. The
qualitative risk ratings can be used in the qualitative economic impact
assessment module (see annex 1) and the quantitative risk ratings in the
quantitative economic impact assessment module (see PRATIQUE
Deliverable D2.5). Rating guidance for qualitative risk ratings is provided
directly after the questions. In the case questions are limited adjusted,
examples of performed PRA are given. The organisms are Rhabdoscelus
obscurus, Raoiella indica, Drosophila suzukii and Hydrocotyle ranunculoides.
4.2
Adjustments of the scheme
2.1 How great a negative effect does the pest have on crop yield and/or
quality to cultivated plants or on control costs within its current area of
distribution?
Note: factors to consider are types, amount and frequency of damage and
crop losses in yield and quality, together with costs of treatment.
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
6.01 How great a negative effect does the pest have on crop yield and/or
quality of cultivated plants or on control costs within its current area of
distribution?
Note: Effect on crop yield and/or quality are usually expressed as a relative
decrease (%) per crop per ha or relative increase in total control costs. When
following the rating guidance, it is important to take into account the annual
variation in crop yield and quality that normally occurs in different crops. For
some crops, e.g. those grown in protected conditions, such as tomatoes, cut
flowers and pot plants, the annual yield fluctuations are normally very small
and a yield loss greater than 10% can be considered as a massive impact.
For crops with high yearly fluctuations, e.g. fruit and arable products and a
loss of more than 50% would be needed before it can be considered to be a
massive impact. Other crops, such as nursery stock, outdoor vegetables and
forestry, take an intermediate position. The main causes of the fluctuation are
due to the weather and the lower amount of protection provided, the higher
the annual variation in yield. Other aspects to be taken into account include
10
biennial bearing (e.g. fruit) which increases yield variation, whether the
product is a bulk product (maize) or a high quality product (e.g. roses) and
whether the product is harvested annually (e.g. vegetables). The more quality
is an important product feature, the lower the yield variation is. If product the
production cycle takes more than one year (e.g. forestry), yield variation due
to weather conditions are levelled. In annex 2, a decision tree is presented to
determine the yield variation for the product.
minimal, minor, moderate, major, massive
Level
of Low
Medium
uncertainty:
High
Rating guidance:
Minimal: no yield and/or quality losses recorded.
Minor: yield and/or quality losses recorded but pest is fully controlled by nontargeted measures and control costs cannot be distinguished from normal
plant protection costs.
Moderate: yield and/or quality losses are limited, some targeted measures
needed, but additional control costs are limited.
Major: yield and/or quality losses are considerable, targeted measures are
frequently needed and the treatment is costly.
Massive: yield and/or quality losses are severe; high mortality of plants may
also occur which can only be reduced by very expensive measures.
Examples (the final judgement is based on the worst case):
Rhabdoscelus obscurus: Minor to moderate.
 Palm trees: Minor to Moderate
Halfpapp & Storey (1991) performed a survey of 22 palm-nurseries in
Queensland (Australia) and interviewed the growers of these nurseries.
Seventeen out of the 22 growers had problems with R. obscurus ranging from
mild to severe. The 5 nurseries without the problems with the palm weevil
were either recently established or had heavy chemical control programs
which suggested that frequent application of insecticides may sufficiently
control the weevil. According to NIAA (1998): R. obscurus is a serious
problem to palm growers in Queensland and causes a loss of public
confidence in palms in public and private landscaping. Presently, the palm
nursery industry in Queensland and New South Wales report minor
occurrence of this pest on a cyclical basis. Palm growers use
organophosphate insecticides when R. obscurus is encountered and consider
it to be a minor pest (pers. comm. M. Ashton, Biosecurity Queensland,
Australia).
 Banana: Minor
Mungomery (1937 cited in Halfpapp & Storey, 1991) did not know of any
bananas being attacked in Queensland. Fay (2001) reported that palm
nurseries in north Queensland have had to face increasing problems with R.
obscurus since 1991. Bianchi & Owen (1965) performed a survey on several
islands in the Great Pacific Ocean: no records could be found on damage
levels in banana in the literature.
11
Raoiella indica: Minimal to major
 Coconut: Major
Information on damage and related yield losses varies. Information from
coconut growers in Trinidad indicate that production was reduced by 75%
percent, two years after introduction of the mite (Duncan et al., 2006)
although a causal relationship has not been demonstrated. There are
reports of severe foliage damage on coconut plantations, young palms and
seedlings in India, but no indication of its effect on yield (Sathiamma 1996;
Jeppson et al., 1975). Raoiella indica may cause yield loss in nuts of Areca
catechu L. (Betel nut palm) when infestations are lingering and severe
(Puttarudriah & Channa Basavanna, 1958). (Uncertainty is medium
because of the lack of data on yield losses from countries where it is
present e.g. India)
 Date palms: minimal
In date palms it is not considered as an economically important pest in the
Near-East (Elwan, 2000; Zaid & Arias-Jimenez 2002, Gerson et al. 1983).
The EWG considered that the lack of published information on damage on
date palms and ornamental palms from Israel, Egypt, Oman and Iran is an
indication of the minor importance of the pest in these areas.
 Bananas: minimal
There is severe yellowing on bananas, but no quantitative data on crop
yield reduction with damage recorded on leaves in Puerto Rico, Trinidad
and Tobago and Venezuela. Damage on leaves due to other pests may be
confused with R. indica (Kane et al., 2006; Welbourn, 2007). There are no
reports of damage on banana in Israel.
 Ornamentals: minimal
There is no evidence of loss of quality in ornamentals (gingers, Heliconia
and Strelitzias) used for planting or as cut flowers.
Drosophila suzukii: massive;
In California, Oregon and Washington crop losses of up to 100% in some
fields have been reported. In Willamette Valley (Oregon) peach growers
experienced losses of up to 80 percent in some orchards (Herring, 2009).
In the part of the PRA area where the pest has been detected the situation is
as follows:
In 2010 losses of up to 80% occurred in strawberry crops of the Alpes
Maritimes region of southern France (pers. comm. Reynaud, 2010). Similar
losses have also been quoted in the Province of Trento in raspberries (pers.
comm. Grassi, 2010).
Hydrocotyle ranunculoides: Major
In the Netherlands, some water boards faced a doubling of costs each year
during the 1990s, and, in 2000, the total annual control costs were around 1
million euros (van der Krabben & Rotteveel, 2003). In 2007, in the
Netherlands, 11 water boards out of 26 responded to an inquiry stating that
they spent an additional 1.8 million euros for the management of H.
ranunculoides over and above normal operating costs for this plant (van
Valkenburg, pers. comm., 2009).
12
In Flanders, the estimated cost for the management of H. ranunculoides is 1.5
million euros per year (needed during 3 years from 2009) (Triest, pers.
comm., 2009).
In the UK, the estimate for control of the total area infested by H.
ranunculoides by herbicides was between £250,000 and £300,000 per year
(Harper, 2002). In 2008, £1.93 million were spent on the management and
disposal of H. ranunculoides (Newman, pers. comm., 2009). In 6 years, the
costs were multiplied 7 times.
Xanthomonas axonopodis pv. allii: Major
In countries where it is present Xanthomonas axonopodis pv. allii has caused
significant yield losses of onions and high control costs when conditions have
been suitable. Xanthomonas pv. allii negatively affects bulb size of onions
because it destroys the foliage thus reducing yield. In the continental United
States, yield losses in onions crops ranging from 10 to 50% were reported
(Nunez et al., 2002; Schwartz & Otto, 2000). In Réunion Island, yield losses of
up to 50% were also recorded (Pruvost, unpublished data). Data from
Barbados indicates cases where an entire onion crop loss was observed (O’
Garro & Paulraj, 1997).
2.2 How great a negative effect is the pest likely to have on crop yield
and/or quality in the PRA area without any control measures?
Note: the ecological conditions in the PRA area may be
adequate for pest survival but may not be suitable for pest
populations to build up to levels at which significant damage is
caused to the host plant(s). Rates of pest growth,
reproduction, longevity and mortality may all need to be taken
into account to determine whether these levels are exceeded.
Consider also effects on non-commercial crops, e.g. private
gardens, amenity plantings.
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
2.11 How likely is it that natural enemies, already present in the PRA
area, will not reduce populations of the pest below the economic
threshold?
Note: For pest plants, natural enemies include herbivores and
pathogens.
Level
uncertainty:
very unlikely, unlikely, moderately likely, likely, very likely
of Low
Medium
High
New question
6.02 How great a negative effect is the pest likely to have on crop yield
and/or quality of cultivated plants in the PRA area without any control
measures?
13
Note: This information can be derived from trials where no
measures are taken on some plots. Consider the note and the
answer to question 6.01. The ecological conditions in the PRA
area may be adequate for pest survival but may not be
suitable for pest populations to build up to levels at which
significant damage is caused to the host plant(s). Rates of
pest growth, reproduction, longevity and mortality may all
need to be taken into account to determine whether these
levels are exceeded despite the presence of natural enemies.
Consider also the effects on non-commercial crops, e.g.
private gardens, amenity plantings.
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
Minimal: no yield and/or quality losses are expected
Minor: yield and/or quality losses are expected but they cannot be
distinguished from normal variation
Moderate: yield and/or quality losses are limited but they exceed normal
variation, some
targeted measures may be necessary
Major: yield and/or quality losses can be considerable, targeted measures
may frequently be needed
Massive: yield and/or quality losses will be severe; and/or high mortality of
plants is expected
Examples:
R. obscurus: Minor
The effect is expected to be limited since it seems unlikely that large
populations will
build up in glasshouses and most damage will be caused by the import of
infested plants
from areas where the pest is present and not from new infestations in the PRA
area.
Raoiella indica: Minor
The main host where damage is recorded (coconut) is present in very low
quantities in the EPPO region (beach landscape in Canary Islands). There is
banana production in the EPPO region, but the crop yield reduction due to R.
indica on banana is unknown.
No judgement can be made for ornamental plants as there is no information.
Phoenix canariensis is recorded as a host but there is no specific evidence of
yield loss.
Drosophila suzukii: massive
Based on the information available regarding significant damage already
occurring within the PRA area, the the likelihood of 'massive' negative effects
on crop yield is considered to be high.
However, recent experiences in North America since 2008 have shown that,
14
although there are annual variations in pest populations, the impact of this
species on local agriculture tends to decrease due to increased awareness,
improved monitoring, and more effective targeting of treatments (pers comm.
Hueppelsheuser and Hauser, 2010).
Hydrocotyle ranunculoides: Minimal
There are currently no impacts recorded in crops, but it was considered that
flooding of low lying agricultural areas is possible due to blockage of water
level control structures.
New question:
6.03 How great a negative effect is the pest likely to have on yield and/or
quality of cultivated plants in the PRA area without any additional
control measures?
Note: Consider the note and answer to question 6.01 and
consider the pest survival and population growth when
producers only apply current crop protection measures.
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
Rating guidance:
Minimal: no yield and/or quality losses are expected.
Minor: yield and/or quality losses are expected but they cannot be
distinguished from normal variation and are insufficient to justify additional
measures.
Moderate: yield and/or quality losses are limited, some targeted measures
may be necessary.
Major: yield and/or quality losses can be considerable, targeted measures
may be frequently be needed.
Massive: yield and/or quality losses will be severe; high mortality of plants is
expected.
2.3 How easily can the pest be controlled in the PRA area without
phytosanitary measures?
Note: Consider the existing control measures and their
efficacy against the pest. Difficulty of control can result from
such factors as lack of effective plant protection products
against this pest, resistance to plant protection products,
difficulty to change cultural practices, occurrence of the pest
in natural habitats, private gardens or amenity land,
simultaneous presence of more than one stage in the life
cycle, absence of resistant cultivars.
very easily, easily, with some difficulty, with much difficulty, impossible
Level
of Low
Medium
High
uncertainty:
15
6.04 How great a negative effect is the pest likely to have on yield and/or
quality of cultivated plants in the PRA area when all potential measures
legally available to the producer are applied, without phytosanitary
measures?
Note: Consider the note and answer to question 6.01. Take
into account the existing and potential control measures and
their efficacy against the pest. Difficulty of control can result
from such factors as lack of effective plant protection products
against this pest, resistance to plant protection products,
difficulty to change cultural practices, occurrence of the pest
in natural habitats, private gardens or amenity land,
simultaneous presence of more than one stage in the life
cycle, absence of resistant cultivars.
Include both normal farm practice costs and costs of control of
measures which are additional to the common agricultural
practice and which are assumed to be taken from a sound
managerial perspective, in particular:
- ease of detection of the pest: species that are difficult to
detect will require a greater surveillance and monitoring effort
which will indirectly result in higher production costs.
- treatment: treatment options may vary (plant protection
products, physical removal, etc.) Treatment costs may be
divided into operating (e.g. chemical, fuel, equipment) and
labour (i. e. hours per ha).
minimal, minor, moderate, major, massive
Level
of Low
Medium
High
uncertainty:
Rating guidance:
Minimal: no yield and/or quality losses expected.
Minor: yield and/or quality losses are expected or cannot be distinguished
from normal variation.
Moderate: yield and/or quality losses are limited
Major: yield and/or quality losses can be considerable.
Massive: yield and/or quality losses will be severe; high mortality of plants is
expected.
2.4 How great an increase in production costs (including control costs)
is likely to be caused by the pest in the PRA area?
Note: both normal farm practice costs and costs of control
should be included, in particular:
- ease of detection of the pest: species that are difficult to
detect will require a greater surveillance and monitoring effort
which will indirectly result in higher production costs.
- treatment: treatment options may vary (plant protection
products, physical removal,…). Treatment costs may be
divided into operating (e.g. chemical, fuel, equipment) and
labour (i. e. hours per ha).
minimal, minor, moderate, major, massive
16
Level
uncertainty:
of Low
Medium
High
6.05 How great an increase in production costs (including control costs)
is likely to be caused by the pest in the PRA area in the absence of
phytosanitary measures?
Note: This is evaluated on the basis of the relative increase
(%) in total costs (e.g. €). Include the costs of all additional
measures which are considered in question 5.04 and costs
incurred to prevent environmental impacts. Consider also the
answer to question 6.02.
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
Rating guidance:
Minimal: no increase of costs expected.
Minor: additional costs are negligible.
Moderate: some targeted measures needed, with limited additional costs.
Major: targeted measures frequently needed, which are expensive.
Massive: targeted measures intensively used which are very expensive.
Examples
Rhabdoscelus obscurus: Minor
The pest is difficult to control. Production costs will increase due to extra
applications of crop protection products and due to plant losses (symptomatic
plants can not be sold and will have to be destroyed). Costs for crop
protection in glasshouse horticulture are, however, relatively low. For pot
plants in general the costs for crop protection agents are about 0.4% of the
total production costs (Lauwere & Bremmer, 2006). Costs for crop protection
(including labour and fertilizers) are about 1 and 2 % of the total production
costs for Chamaedorea and Chrysalidocarpus lutescens (Van Woerden,
2005). Thus the increase in production costs will be mainly determined by the
loss of plants due to the pest. These losses are, however expected to be
mainly limited to plants that had already been infested prior to import.
Raoiella indica: Minimal
The main host where damage is recorded (coconut) is present in very low
quantities in the EPPO region (beach landscape in Canary Islands). There is
banana production in the EPPO region, but the crop yield reduction due to R.
indica on banana is unknown.
No judgement can be made for ornamental plants as there is no information.
Phoenix canariensis is recorded as a host but there is no specific evidence of
yield loss.
Drosophila suzukii: Moderate
Costs will be incurred for labour and materials associated with monitoring,
sanitation management, and additional targeted applications of plant
protection products. Due to limited experience in areas experiencing D.
17
suzukii infestations, there is some uncertainty regarding exactly how
expensive control and management strategies may be. Optimal control
management strategies are yet to be well defined and these may or may not
incur increased costs in terms of chemical use and/or labour.
Hydrocotyle ranunculoides: Moderate to major
Control costs could be similar to those already spent in infested parts of the
PRA area. A weevil, Listronotus elongatus, has been demonstrated to feed
exclusively on Hydrocotyle species in Argentina, and further work on this
potential bio-control agent is planned in the UK (Newman, 2003). The cost of
a preliminary study was £30.000, but the cost of a full biological control project
would be £500.000 (Newman, pers. comm., 2009).
2.10 How likely is the presence of the pest in the PRA area to cause
losses in export markets?
Note: consider the extent of any phytosanitary measures likely
to be imposed by trading partners.
Impossible/very unlikely, unlikely, moderately likely, likely, very
likely/certain
Level
of Low
Medium
High
uncertainty:
6.06 Based on the total market, i.e. the size of the domestic market plus
any export market, for the plants and plant product(s) at risk, what will
be the likely impact of a loss in export markets, e.g. as a result of trading
partners imposing export bans from the PRA area?
Note: consider whether plant products potentially affected by
the pest are exported from the PRA area and how important
such exports are, for example by estimating the proportion of
production that is exported. Take into account the major
existing (or potential) export markets and how likely each is to
impose an export ban from the PRA area. This is expressed
as a relative decrease in market size.
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
Rating guidance
Minimal: no effect on market size is expected.
Minor: the effect on market size is negligible and cannot be distinguished
from normal variation.
Moderate: some effects on market size are expected.
Major: considerable effects on market size are expected.
Massive: severe effects on market size are expected.
Examples
Phytophthora ramorum causes damage to a range of host plants in nursery
stock. It is likely that infestation in Europe will cause export bans in the USA
18
and Canada. However, these export markets are of limited importance.
Therefore, the score is ‘minor’.
Meloidogyne chitwoodi leads to minor or moderate yield loss in potato
production. Although M. chitwoodi has the quarantine status in some export
countries, the presence of M. chitwoodi in some parts of the EU has not
reduced the exported volume to these countries. Therefore, the score is
‘minor’.
Anoplophora glabripennis larvae feed beneath the bark and then bore into
the wood. This may kill forest and amenity trees and reduce the quality of
timber because of bore-holes. The most important threat is the reduction of
export of trees and wood because of the quarantine status of this organism in
most parts of the world. Because of the relative importance of export the score
is ‘major’.
2.5 How great a reduction in consumer demand is the pest likely to
cause in the PRA area?
Minimal extent, minor extent, moderate extent, major extent, massive
extent
Level
of Low
Medium
High
uncertainty:
6.07 To what extent will direct impacts be borne by producers?
Note: This is evaluated as the proportion (%) of total economic
impact (the sum of the questions 6.04, 6.05 and 6.06) borne by the
producers. Producers can try to transfer economic losses to
consumers and to other producers in order to decrease impacts on
themselves.
Factors that enable producers to decrease impacts include:
- the alternative use of the product, e.g. a shift from human
consumption to use for animal feed
- the negotiation power of the producer to change the price of the
product,
- the potential to grow other crops. The ease with which production
can be adjusted depends on:
- the time needed for new crops to reach full production, e.g.
one season for potatoes and several years for apples,
- the availability of factors such as labour, land and the
investments which may have to be made to increase
production (investment in plants for planting, buildings such
as glasshouses, etc.),
- factors such as market expectations and the potential for
storage of the product until prices rise.
Factors that limit producers capacity to decrease impacts include:
- consumer responsiveness (can consumers postpone consumption
or shift to substitutes?),
- reductions in market share due to loss of image or dependency on
the harmed products, such as wood which is used as packaging
19
material. This can also affect the sale of products which are not
infested.
A producer will almost never be able to pass on all costs. More
details including a decision tree to derive indirect impacts are
presented in Annex 3.
Level
uncertainty:
Option 1: minimal, minor, moderate, major, massive
of Low
Medium
High
Option 2: no judgment possible/ ask an economist
When no judgment is chosen, the assessor should specify in the PRA that the
impact may be overestimated.
Rating guidance (see annex 2)
Minimal: almost totally decrease of direct impacts because prices increase
due to lack of any possibilities for consumers to use alternatives or to
postpone consumption
Minor: direct impacts decrease largely because prices increase due to limited
possibilities for consumers to use alternatives or to postpone consumption
Moderate: direct impacts decrease partly because prices increase somewhat
due to some possibilities for consumers to use alternatives or to postpone
consumption or the producers has some possibilities to shift to alternative
products.
Major: direct impacts decrease slightly because prices almost don’t increase
due to possibilities for consumers to use alternatives or to postpone
consumption and the producers has limited possibilities to shift to alternative
products.
Massive: decreasing direct impacts cannot be expected because prices don’t
increase due to possibilities for consumers to use alternatives or to postpone
consumption and the producers has no possibilities to shift to alternative
products.
20
5
Indicators and scoring systems for social impacts
In this chapter adjustments to the questions regarding social impacts are
presented. The old questions numbered with 2.x are followed by new
questions numbered with 6.x. Rating guidance for qualitative scores is
provided.
2.8 How important is social damage caused by the pest within its current area
of distribution?
Note: Social effects may arise as a result of impacts to commercial
or recreational values, life support/human health, biodiversity,
aesthetics or beneficial uses. Social effects could be, for example,
changing the habits of a proportion of the population (e.g. limiting
the supply of a socially important food) damaging the livelihood of a
proportion of the human population, affecting human use (e.g.
water quality, recreational uses, tourism, animal grazing, hunting,
fishing). Effects on human or animal health, the water table and
tourism could also be considered, as appropriate, by other
agencies/authorities.
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
6.10 How important is social damage caused by the pest within its
current area of distribution?
Note: Social effects are impacts on human well-being, other than
economic impacts. The main social effects are:
• Landscape effects. To assess the impacts on the landscape two
elements need to be involved:
o Land use function (agriculture, living area)
o Contribution to wellbeing (aesthetic value, cultural/
historic value)
• Loss of employment
• Effects on human health (in addition to effects on plant health)
• Products and services such as water quality, animal grazing,
hunting and fishing (in addition to effects on plant health).
Effects on human or animal health, the water table and tourism could be
considered, as appropriate, by other agencies/authorities.
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
Rating guidance landscape effects
Minimal: damage to landscape has no consequences for landscape value
Minor: some plants which play an important role in determining the
attractiveness of the landscape are damaged or die
21
Moderate: some plants that play an important role in determining the
attractiveness of the landscape are damaged or die
Major: a substantial proportion of the plants that play an important role in
determining the attractiveness of the landscape are damaged or die
Massive: the majority of the plants that play an important role in determining
the attractiveness of the landscape die.
Rating guidance for loss of employment
Minimal: No loss of employment occurs due to economic impact occurs
Minor: Some loss of employment due to economic impacts may occur, but
cannot be distinguished from normal loss of employment
Moderate: Loss of employment due to economic impacts occurs to a limited
extent
Major: Considerable loss of employment and bankruptcy due to economic
impacts occurs
Massive: Due to economic impacts, the majority of the affected producers go
bankrupt and their employees loose there job
Combined rating guidance:
Take the maximum score of landscape effects and loss of employment
NB! No rating guidance for human health effects and products and services
will be provided in order to ensure that the risk rating for this question will not
be dominated by these aspects. Effects on human health and products and
services should be reported as additional comments.
Example
Phytophthora ramorum causes damage to different host plants in managed
gardens. Since some of these plants play an important role in determining
the attractiveness of the landscape (and may thus influence the number of
tourists), the score is at least moderate. In areas where most of these plants
are hosts, the score can be major or massive.
2.9 How important is the social damage likely to be in the PRA area?
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
6.11 How important is social damage likely to be in the PRA area?
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
Rating guidance landscape effects
Minimal: damage to landscape has no consequences for landscape value
Minor: some plants which do not play an important role in determining
the attractiveness of the landscape are damaged or die
22
Moderate: some plants that play an important role in determining the
attractiveness of the landscape are damaged or die
Major: a substantial proportion of the plants play an important role in
determining the attractiveness of the landscape are damaged or die
Massive: the majority of the plants that play an important role in determining
the attractiveness of the landscape die.
Rating guidance loss of employment
Minimal: No loss of employment occurs due to economic impacts
Minor: Some loss of employment due to economic impacts may occur, but
cannot be distinguished from normal loss of employment
Moderate: Loss of employment due to economic impacts occurs to a limited
extent
Major: Considerable loss of employment and bankruptcy due to economic
impacts occurs
Massive: Due to economic impacts, the majority of the affected producers go
bankrupt and their employees loose there job
Combined rating guidance:
Take the maximum score of landscape effects and loss of employment
NB! No rating guidance for human health effects and products and services
should be provided in order to ensure that the risk rating for this question will
not be dominated by these aspects. Effects on human health and products
and services should be reported as additional comments.
23
6
Indicators and scoring systems for environmental
impacts
6.1 Introduction
In this chapter, the two questions (2.6 and 2.7) about the environmental
impacts are converted into a set of questions, covering all different aspect of
environmental impacts. Rating guidance has been provided as well as
examples. Finally, a rating system has been presented to summarize the
scores of the sub-questions into a final score for environmental impacts.
Furthermore, two separate sets of questions have been provided for plant
pests and for pest plants.
6.2 Questions for plant pests
6.08. How important is the environmental impact caused by the pest
within its current area of invasion?
(former question 2.6)
N/A, Minimal, minor, moderate, major, massive
In this question we rate the current environmental impact in other invaded
regions that can be used as indicator for determining the potential
environmental impact in the PRA area (Q. 6.09).
If the species has not invaded any other area, or if the invasion is too recent
and too little is known about its ecology in the invaded areas, this question
cannot be answered properly (assuming that no additional investigations can
be undertaken during the time available for producing the PRA). The assessor
may choose to go directly to Q 6.09. He/she may also choose to answer these
questions based on well studied closely-related species or data for the target
species from the region of origin. Although the concept of “environmental
impact” of an indigenous species on native biodiversity and ecosystem is
debatable, in some cases native species clearly have an environmental
impact, usually resulting either from climate change or ecological
mismanagement (e.g. Dendroctonus ponderosae presently causing serious
outbreaks and extending its range in Canada, various weeds now invasive in
their native range, etc.). Nevertheless, the assessor should take into account
the fact that the environmental impact of a pest in its region of origin is often a
very poor predictor of potential impact in regions where it has been
introduced. In particular, the absence of any obvious environmental impact in
a region of origin should not be considered as a predictor for a low impact in a
new area.
Examples of species for which Q. 6.08 may be difficult to answer include:
- Choristoneura fumiferana and Pissodes strobi: These North American
species have never invaded any area.
- Anoplophora glabripennis and A. chinensis: For the moment (2010) all
outbreaks in invaded areas worldwide are still under eradication and the
24
-
-
beetle has not yet been studied in natural areas or even semi-natural
forests in invaded areas.
Diaphania perspectalis and Paysandisia archon: Their invasion in Europe
is too recent to accurately assess their current impacts, and they have
never invaded any other region.
Most pathogens and strictly agricultural pests have been poorly studied for
their environmental impact.
When data on impact are available in several invaded regions, priority should
be given to impact observed in regions that are most closely related,
geographically and eco-climatologically, to the PRA region. However, data
from other regions should not be excluded. For example, when performing a
PRA on an invasive pest for the entire Europe, data on impact already
observed in Europe should be given priority, but information from other
regions should also be provided. In any case, the assessor should specify the
region where the information on impact has been gathered.
6.08.0A Based on the above, do you consider that the question on the
environmental impact caused by the pest within its current area of
invasion can be answered?
If Yes: Go to 6.08.01
If No, but information is available for the native area of the pest, Go to
6.08.01.
If No, but there is some evidence that the environmental impact may be
significant in the PRA area: answer N/A for 6.08 and Go to 6.09.0C
If No, and the assessor is certain that, in any case, the environmental
impact will be lower than the economic impact (e.g. a purely agricultural
pest not known to occur in other environments): answer N/A for 6.08 and
6.09 (the assessor will have to justify this decision).
The pest has to be assessed for three categories of impact using several
indicators that need to be rated. The precise region (and whether invaded or
native) and the species (target species or closely-related species) for which
the question is answered should be clearly described by the assessors.
The subquestions to be answered are organized as follows:
Negative impact on native biodiversity
6.08.01. To what extent does the pest cause a decline in native species?
6.08.02. To what extent does the pest cause changes in the composition and
structure of native species communities?
6.08.03. To what extent does the pest hybridize with native species?
Alteration of ecosystem processes and patterns
6.08.04. To what extent does the pest cause physical modifications of
habitats?
6.08.05. To what extent does the pest cause changes in nutrient cycling and
availability?
6.08.06. To what extent does the pest cause modifications of natural
successions?
6.08.07. To what extent does the pest disrupt trophic and mutualistic
interactions?
25
Conservation impacts
6.08.08. To what extent does the pest occur in habitats of high conservation
value?
6.08.09. To what extent does the pest cause harm to rare or vulnerable
species?
For each of the indicators, a rating is given based on three choices: Low,
Medium or High. Information is provided for each indicator on the meaning of
these scores.
For each answer, the associated uncertainty should also be assessed, the
possible options are Low, Medium or High.
Low: the assessor has low uncertainty that the rating is correct (i.e. the impact
has been studied and measured, or the observed damage, the bio-ecological
characteristics of the species, or the environmental conditions allow the
assessor to be highly confident of the accuracy of the rating).
Medium: The assessor has moderate uncertainty that the rating is correct (i.e.
the impact has been studied but some contradictory results have been
identified, or the observed damage, the bio-ecological characteristics of the
species, or the environmental conditions allow the assessor to be moderately
confident of the accuracy of the rating).
High: The assessor has high uncertainty that the rating is correct (i.e. the
impact has been studied but the results are contradictory, or the observed
damage, the bio-ecological characteristics of the species, or the
environmental conditions do not allow the assessor to be moderately
confident of the accuracy of the rating).
Negative impact on native biodiversity
Note 1: The word “native” in “native species” or “native biodiversity”
throughout Questions 6.08 and 6.09 should be understood in a broad sense,
i.e. it should also include species that have been naturalised for centuries and
that play an important role in the ecosystems or local cultural heritage, such
as walnut (Juglans) or chestnut (Castanea) in Europe. The assessor may also
include other, more recently introduced beneficial organisms such as
biological control agents or exotic plants that play a role in ecosystem
services, e.g. plants used against erosion.
Note 2: If possible, all mechanisms of impact on native biodiversity should be
considered, but only the mechanism providing the highest score and lowest
uncertainty is kept for the scoring of the indicators. Mechanisms of impact
may include, among others:
Herbivory: Most impacts by plant pests occur through direct feeding on native
plants. E.g., the emerald ash borer Agrilus planipennis feeds on, and kills
native Fraxinus spp. in North America. The hemlock woolly adelgid, Adelges
tsugae, severely affects natural stands of Tsuga spp. in Eastern North
America.
26
Plant pathology: A pathogen directly impacts its host plant by causing
disease, e.g. Ophiostoma novo-ulmi decimated Ulmus spp. by causing Dutch
elm disease in Europe and North America. Nematodes may also cause plant
disease, e.g. Bursaphelenchus xylophilus causes pine wilt, which devastates
native pine stands in East Asia.
Disease transmission: Alien pests can affect native plants through disease
transmission, e.g. Scolytus multistriatus, a European bark beetle, is a vector
of the Dutch elm disease in North America. This can also include pests that
facilitate the attack of a pathogen, without being vectors themselves. For
example, the European beech scale, Cryptococcus fagisuga, increases the
susceptibility of the fungus Neonectria faginata, causal agents of the beech
bark disease in North America.
Hybridization: Hybridization between an alien and a native species or subspecies may affect the genetic identity of native species or sub-species,
although well documented examples are rare for plant pests. The Australian
lycaenid butterfly Zizina labradus has apparently locally displaced the
endemic Z. oxleyi in New Zealand. In insects, examples are most common
between alien and native honey-bee and bumble-bee sub-species.
Competition for resources: Alien herbivores may affect native biodiversity by
competing for food or by affecting the quality and availability of food. For
example, the scale insect Icerya purchasi, by killing endangered plants in the
Galapagos, has also caused local extinction of host specific Lepidoptera. In
North America, the Asian adelgid Pineus boerneri, is displacing P.
coloradensis in red pine plantations, by reducing host plant quality and forcing
the native species to move to other hosts.
Predation: Plant pests may also affect native species through predation on
other animals. For example, the ladybird Harmonia axyridis, a pest of
vineyards in North America also affects native ladybird populations through
predation.
Apparent competition: Apparent competition occurs when the presence of one
species indirectly decreases the fitness of another through the increased
presence of a shared enemy. An example is the variegated leafhopper,
Erythroneura variabilis, which, when introduced into California, affected
populations of the native E. elegantula by enhancing populations of a shared
egg parasitoid.
Pesticide use: An intensive use of non-specific pesticides (including
biopesticides) over wide areas may affect native biodiversity, in particular
when used in natural or semi-natural habitats (e.g. forests, swamps, etc.) . For
example, the use of Bt over wide areas in North America to control Lymantria
dispar locally affects the Lepidopteran fauna; the chemical control of alien
mosquitoes over wide areas worldwide has a negative impact on the aquatic
fauna.
27
6.08.01. To what extent does the pest cause a decline in native species?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
The decline in native species populations has been studied but not
observed. If no study has been carried out to determine the level of
impact, according to the information available on observed damage,
bio-ecological characteristics of the species and environmental
conditions, a decline in native species is unlikely.
Examples: The impact of alien gall wasps Andricus spp. on native
gall wasps in Britain has been studied but no significant impact was
found. Phytophthora infestans mainly attack cultivated crops in
Europe and the effect on native species populations is unlikely.
Medium A decline in native species populations has been observed but the
decline is not persistent and is limited in area. If no study has been
carried out to determine the level of impact, according to the
information available on observed damage, bio-ecological
characteristics of the species and environmental conditions, the
impact level is considered to be medium.
Examples: Severe outbreaks of Lymantria dispar in North America
are known to cause local decline in host trees and associated fauna
(e.g. birds), but most studies suggest that the decline is usually
temporary. Cryphonectria parasitica has severely affected
populations of European chestnut when it arrived in Europe, but
chestnut forests have largely recovered.
High
AO decline in native species populations has been observed, and
the impact is likely to be widespread within the habitats occupied by
the species and persistent if no management option is taken. If no
study has been carried out to determine the level of impact,
according to the information available on observed damage, bioecological characteristics of the species and environmental
conditions, the impact level is considered to be high.
Examples: Adelges piceae has decimated natural Fraser fir
populations in Eastern North America. Ophiostoma novo-ulmi has
caused the general decline of elm species in Europe and North
America. Although studies to accurately measure the impact of
Agrilus planipennis on populations of several ash species in North
America are still lacking, the fact that the beetle has already killed
over 40 million trees and the prediction that the damage is going to
continue unabated for the foreseeable future strongly suggests that
it has a severe effect on ash populations and the associated fauna.
28
6.08.02. To what extent does the pest cause changes in the composition
and structure of native species communities?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
Changes in native community composition and structure have been
studied but not observed. If no study has been carried out to
determine the level of impact, according to the information available
on observed damage, bio-ecological characteristics of the species
and environmental conditions, a decline in native community
composition and structure is unlikely.
Examples: All alien pests and pathogens attacking mainly or
exclusively crop species will fall into this category. Species (e.g.
Lilioceris lilii) that are specific to plants species that do not, or rarely
dominate plant communities (e.g. lilies) will also score Low here.
Medium Changes in native community composition and structure have been
observed but the changes are not persistent and limited in area. If
no study has been carried out to determine the level of impact,
according to the information available on observed damage, bioecological characteristics of the species and environmental
conditions, the impact level is considered to be medium.
Examples: Defoliation by Lymantria dispar can cause a major shift
in tree species in North America either through tree mortality or via
seed failure or mortality of oak seedling. Bird communities may also
be modified. However, in general, defoliations by L. dispar only
induce temporary changes.
High
Significant changes in native community composition and structure
have been observed and the impact is likely to be widespread within
the habitats occupied by the species and persistent if no
management option is taken. If no study has been carried out to
determine the level of impact, according to the information available
on observed damage, bio-ecological characteristics of the species
and environmental conditions, the impact level is considered to be
high.
Examples: Mortality of Fraser fir caused by Adelges piceae in North
America has totally altered plant communities in these forest
ecosystems. Cryphonectria parasitica has had a same effect on
plant communities associated to American walnut forests. The
decline of eastern hemlock due to Adelges tsugae in North America
strongly affects bird species composition.
29
6.08.03. To what extent does the pest hybridize with native species?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
Hybridization with native species has been studied but has not been
observed. If no study has been carried out to determine the level of
impact, according to the information available, hybridization with
native species is very unlikely.
Examples: All alien species without taxonomically very closely
related species (congeneric sister-species or sub-species) will fall
into this category.
Medium Hybridization with native species/subspecies has been observed in
the field or in the lab, but no fertile offspring have been produced, or
if fertile offspring have been produced, the hybrid has a lower
fitness than its parents and will not replace the native
species/subspecies. If no study on hybridization has been carried
out, hybridization is considered possible because of the presence of
sister species or subspecies in the invaded area.
Examples: Hybridization between alien and native Bombus spp. is
obtained in the laboratory, but their offspring is usually sterile. In
Japan, fertile hybridization is obtained in the lab between the native
parasitoid Torymus beneficus and the alien T. sinensis, but studies
showed that hybridization in the field was marginal.
High
Hybridization with native species/subspecies has been observed in
the field or in the laboratory and fertile offspring have been
produced. The hybrid has a high fitness and is replacing, or is able
to replace the native species or sub-species. If no study on
hybridization has been carried out, fertile hybridization is considered
likely because of the presence of sister species or subspecies in the
invaded area and the occurrence of other, similar cases with
taxonomically closely-related species.
Example: The Australian lycaenid butterfly Zizina labradus has
apparently locally displaced the endemic Z. oxleyi in New Zealand.
Introductions in North-Western Europe of two southern European
sub-species of Apis mellifera has caused large-scale gene-flow and
introgression between these sub-species and the native subspecies, whose native populations are now threatened.
Alteration of ecosystem processes and patterns
Note : Only the impact on natural or semi-natural habitats should be
considered when assessing the impact on ecosystem processes and patterns.
30
However, natural and semi-natural habitats have to be considered in a broad
sense, i.e. every habitat that is not under constant human management. It
includes all EUNIS habitat types 1 (http://eunis.eea.europa.eu/habitats-codebrowser.jsp), except I (Regularly or recently cultivated agricultural,
horticultural and domestic habitats) and J (Constructed, industrial and other
artificial habitats). For example, grasslands that are regularly mown are
included as well, but not those that are repeatedly re-seeded.
6.08.04. To what extent does the pest cause physical modifications of
habitats (e.g. changes to the hydrology, significant increase of water turbidity,
light interception, alteration of river banks, changes in fire regime, etc.)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
The physical modification of habitats has been studied but not
observed. If no study has been carried out to assess the impact,
according to the information available on observed damage, bioecological characteristics of the species and environmental
conditions, a physical modification of habitats is unlikely.
Examples: All alien pests and pathogens attacking mainly or
exclusively crop species will fall into this category, as well as those
impacting non-dominant plants, in particular herbaceous plants.
Medium A physical modification of habitats has been observed but the
impact is not persistent and limited in area. If no study has been
carried out to assess the impact, according to the information
available on observed damage, bio-ecological characteristics of the
species and environmental conditions, the impact level is
considered to be medium.
Examples: Defoliations and tree mortality by Lymantria dispar in
North America increases light penetration to the forest floor and
water drainage. These changes are usually considered as
temporary. Tree mortality caused by Elatobium abietinum in
relatively dry areas such as Arizona increases the amount of dry
fuel material in the forest and increases the risk of wildfire.
High
A physical modification of habitats has been observed and the
impact is likely to be widespread within the ecosystem where the
species is present and persistent if no management option is
undertaken. If no study has been carried out to assess the impact,
according to the information available on observed damage, bioecological characteristics of the species and environmental
conditions, the impact level is considered to be high.
Examples: Hemlock mortality due to Adelges tsugae in North
America modifies hydrological processes and the forest floor
microclimate.
31
6.08.05. To what extent does the pest cause changes in nutrient cycling
and availability (e.g. significant changes in nutrient pools in topsoils or in
water)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Changes in nutrient cycling have been studied but not observed. If
Low
no study has been carried out to assess the impact, according to
the information available on observed damage, bio-ecological
characteristics of the species and environmental conditions, a
change in nutrient cycling is unlikely.
Examples: All alien pests and pathogens attacking mainly or
exclusively crop species will fall into this category, as well as those
impacting non-dominant plants, in particular herbaceous plants.
Medium Changes in nutrient cycling have been observed but the impact is
not persistent and limited in area. If no study has been carried out to
assess the impact, according to the information available on
observed damage, bio-ecological characteristics of the species and
environmental conditions, the impact level is considered to be
medium.
Examples: Defoliation by Lymantria dispar in oak forests in North
America alters carbon allocation and nitrogen cycling, which has
consequences such as acidification of stream water. These effects
are usually considered as temporary.
High
Changes in nutrient cycling have been observed and the impact is
likely to be widespread where the species is present and persistent
if no management option is undertaken. If no study has been
carried out to assess the impact, according to the information
available on observed damage, bio-ecological characteristics of the
species and environmental conditions, the impact level is
considered to be high.
Examples: In Western North America, spruce defoliation by
Elatobium abietinum influences short- and long-term nutrient cycling
in forest stands. Nutrient availability may be increased in the shortterm, but over longer periods defoliation may result in a net loss of
nutrients from the stand. Hemlock mortality caused by Adelges
tsugae results in a dramatic increase in inorganic N availability and
the nitrification rate, resulting in nitrate leaching.
32
6.08.06. To what extent does the pest cause modifications of natural
successions (e.g. acceleration or temporary freezing of successions)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
The modification of natural successions has been studied but has
not been observed. If no study has been carried out to assess the
impact, according to the information available on observed damage,
bio-ecological characteristics of the species and environmental
conditions, a modification of natural successions is unlikely.
Examples: All alien pests and pathogens attacking mainly or
exclusively crop species will fall into this category, as well as those
impacting non-dominant plants, in particular herbaceous plants.
Medium A modification of natural successions has been observed but the
impact is not persistent and limited in area. If no study has been
carried out to assess the impact, according to the information
available on observed damage, bio-ecological characteristics of the
species and environmental conditions, the impact level is
considered to be medium.
Examples: Lymantria dispar outbreaks modify natural successions
in defoliated oak forests but changes are only temporary.
High
A modification of natural successions has been observed and the
impact is likely to be widespread within that ecosystem in the
current distribution of the species and persistent if no management
option is taken. If no study has been carried out to assess the
impact, according to the information available on observed damage,
bio-ecological characteristics of the species and environmental
conditions, the impact level is considered to be high.
Examples: Cryptococcus fagisuga facilitates beech bark disease in
North America, which causes long term changes in natural
successions that disadvantages beech. The predation of
Anoplolepis gracilipes on the red land crab in the rain forest of
Christmas Island has totally modified natural successions in this
natural ecosystem.
6.08.07. To what extent does the pest disrupt trophic and mutualistic
interactions (e.g. disruption of food web, pollination or plant-mycorrhiza webs
leading to ecosystem imbalance)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
33
Rating guidance
Low
The disruption of trophic and mutualistic interactions has been
studied but not observed. If no study has been carried out to assess
the impact, according to the information available on observed
damage, bio-ecological characteristics of the species and
environmental conditions, a disruption of trophic and mutualistic
interactions is unlikely.
Examples: Studies have investigated the impact of Cameraria
ohridella on trophic interactions between native leaf miners and
parasitoids, but no impact was found. All alien pests and pathogens
attacking mainly or exclusively crop species will fall into this
category.
Medium A disruption of trophic and mutualistic interactions has been
observed but the impact is not persistent and limited in area. If no
study has been carried out to assess the impact, according to the
information available on observed damage, bio-ecological
characteristics of the species and environmental conditions, the
impact level is considered to be medium.
Examples: Lymantria dispar outbreaks enhance parasitoid
populations, leading to increased parasitism on rare butterfly and
favour mouse populations, leading to an increase in tick populations
and Lyme disease incidence. Linepithema humile displaces floral
arthropods, including pollinators on various plants in South Africa,
but no long term effect on seed sets is observed. The introduction of
Apis mellifera and Bombus terrestris worldwide causes local decline
of native bees and birds which may locally affect pollination.
High
A disruption of trophic and mutualistic interactions has been
observed and the impact is likely to be widespread within that
ecosystem in the current distribution of the species and persistent if
no management option is taken. If no study has been carried out to
assess the impact, according to the information available on
observed damage, bio-ecological characteristics of the species and
environmental conditions, the impact level is considered to be high.
Examples: The strong decline of important trees such as American
chestnut (due to Cryphonectria parasitica), elm species (due to
Ophiostoma novo-ulmi), Fraser fir (due to Adelges piceae) and
Hemlock species (due to Adelges tsugae) undoubtedly has a
strong, long term effect on food webs closely associated with these
trees and their specific herbivores. The introduction of Anoplolepis
gracilipes in Christmas Island and the Seychelles has lead to new
associations with scale insects, leading to important tree mortality
and long-term changes in forest ecosystems.
34
Conservation impacts
6.08.08. To what extent does the pest occur in habitats of high
conservation value (includes all officially protected nature conservation
habitats)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
The pest occurs exclusively, or nearly exclusively outside habitats
of high conservation value.
Examples: In Central Europe, Cameraria ohridella attacks nearly
exclusively horse-chestnut, which is an exotic ornamental tree that
is rarely found in habitats of high conservation values. The Potato
Spindle Tuber Viroid is found nearly exclusively in agricultural and
horticultural habitat.
Medium The pest occurs only occasionally in habitats of high conservation
value or, if it occurs commonly, no major host is an important
component of these habitats (e.g. dominant or keystone species,
ecological engineers, etc.).
Examples: Lilioceris lilii in North America may be found in protected
areas, but its hosts (Lilium spp.) cannot be considered as important
components of these protected habitats. Phyllonorycter robiniella is
restricted to Robinia pseudoaccacia, which occurs occasionally in
protected areas in Europe. However, the host is an alien species
and, so, is not an important component of the protected habitats.
High
The pest occurs commonly in habitats of high conservation value
and at least some major hosts are important ecological components
of such habitats (e.g. dominant or keystone species, ecological
engineers, etc.)
Examples: Adelges tsugae attacks hemlock species in nature
reserves and national parks, where its hosts are keystone species.
Cryphonectria parasitica has nearly eradicated American chestnut,
a keystone tree species of several forest ecosystems in Eastern
America, including in protected areas.
6.08.09. To what extent does the pest cause harm to rare or vulnerable
species (includes all species classified as rare, vulnerable or endangered in
official national or regional lists within the PRA area)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
35
Rating guidance
Low
The pest has no rare or vulnerable species as hosts.
Examples: Agrilus planipennis is restricted to Fraxinus spp But, so
far, none of these species are considered to be rare or vulnerable in
North America. Diabrotica virgifera attacks mainly maize and some
grasses in Central Europe, none of which are rare or vulnerable.
Medium The pest has rare or vulnerable species as minor hosts. “Minor
hosts” means that, if they have already been in contact, severe
damage has never been observed on these hosts. If they have
never been in contact, there is indication that the development on
these hosts is less favourable.
Examples: In North America, no major host of Lymantria dispar is
rare or vulnerable. However, the pest is so polyphagous that, during
outbreaks, the chance that it will feed on rare woody species is
high.
High
The pest has rare or vulnerable species as major hosts. “Major
hosts” include all hosts on which severe damage has been
observed, i.e. damage for which the species has gained its pest
status. If the pest and the host have never been in contact in the
field, laboratory observations suggest that damage may be as high
as on its recognised major hosts.
Examples: In North America, one of the major hosts of Adelges
piceae is Abies fraseri, which is classified as a vulnerable species
by the IUCN. In Florida, Cactoblastis cactorum attacks several
endangered Opuntia spp. and Aulacaspis yasumatsui threatens the
survival of several rare and endangered cycad species.
Final rating:
- Each of the three impact categories will be scored with the highest
indicator score within its category
- A final rating is obtained as follows:
• Massive: 3 x High
• Major: 2 x High and 1 x Medium
• Moderate: 1 x High and at least 1 x Medium or 2 x High and 1 x Low
• Minor: 1 x High and 2 Low or 2 or 3 x Medium
• Minimal: Maximum 1 x Medium, all others Low
36
6.3 Questions for pest plants
Q6.08: How important is the environmental impact caused by the plant
within its current area of invasion? (former question 2.6)
N/A, Minimal, minor, moderate, major, massive
General Concept:
In this question we rate the current environmental impact in other invaded
regions that can be used as an indicator for determining the potential
environmental impact in the PRA area (Q. 6.09). If the species has not
invaded any other area, or if the invasion is too recent and too little is known
about its ecology in the invaded areas, this question cannot be answered
properly, assuming that no additional investigations can be undertaken during
the time available for producing the PRA. The assessor may also choose to
answer these questions based on well-studied closely-related species or on
data for the target species from the region of origin. Although the concept of
the “environmental impact” of a native species on native biodiversity and
ecosystems is debatable, in some cases recently expanding native species
clearly have an environmental impact, resulting from climate change, habitat
change, change in disturbance regime or ecological mismanagement (e.g.
various weeds such as Canada thistle are now expanding in their native
range, etc.). Nevertheless, the assessor should take into account that the
environmental impact of a pest in its region of origin is often a very poor
predictor of potential impact in regions where it has been introduced. In
particular, the absence of any obvious environmental impact in the region of
origin should not be considered as a predictor for a low impact in a new area.
When data on impact are available in several invaded regions, priority
should be given to impact observed in regions that are most closely related,
geographically and eco-climatologically, to the PRA region. However, data
from other regions should not be excluded. For example, when performing a
PRA on an invasive plant for the entire Europe, data on impact already
observed in Europe should be given priority, but information from other
regions should also be provided. In any case, the assessor should specify the
region where the information on impact has been gathered.
5.08.0A Based on the above, do you consider that the question on the
environmental impact caused by the pest within its current area of
invasion can be answered?
If Yes: Go to 6.08.01
If No, but information is available for the native area of the plant, Go to
6.08.01.
If No: Go to 6.09.0C, answer N/A for 6.08
The plant has to be assessed for three categories of impact using several
indicators that need to be rated. The precise region (and whether invaded or
native) and the species (target species or closely-related species) for which
the question is answered should be clearly described by the assessors.
37
The subquestions to be answered are organized as follows:
Negative impact on native biodiversity
6.08.01. To what extent does the plant cause a decline in native species
populations and changes in communities of native species?
6.08.02. To what extent does the plant hybridize with native species?
Alteration of ecosystem processes and patterns
6.08.03. To what extent does the plant cause physical modifications of
habitats?
6.08.04. To what extent does the plant cause changes to nutrient cycling and
availability?
6.08.05. To what extent does the plant cause modifications of natural
successions?
6.08.06. To what extent does the plant disrupt trophic and mutualistic
interactions?
Conservation impacts
6.08.07. To what extent does the plant occur in habitats of high conservation
value?
6.08.08. To what extent does the plant threaten rare or vulnerable species?
For each of the indicators, a rating is given based three choices: Low, Medium
or High. Information is provided for each indicator on the meaning of these
scores.
For each answer, the associated uncertainty should also be assessed, the
possible options are Low, Medium or High:
Low: the assessor has low uncertainty that the rating is correct (i.e. the impact
has been studied and measured, or the invasion status and bio-ecological
characteristics of the plant as well as the characteristics of the invaded
habitats allow the assessor to be highly confident of the accuracy of the
rating).
Medium: The assessor has moderate uncertainty that the rating is correct (i.e.
the impact has been studied but some contradictory results have been
identified, or the invasion status and bio-ecological characteristics of the plant
as well as the characteristics of the invaded habitats allow the assessor to be
moderately confident of the accuracy of the rating).
High: The assessor has high uncertainty that the rating is correct (i.e. the
impact has been studied but the results are contradictory, or the invasion
status and bio-ecological characteristics of the plant as well as the
characteristics of the invaded habitats do not allow the assessor to be
moderately confident of the accuracy of the rating).
Negative impact on native biodiversity
Note 1: The word “native” in “native species” or “native biodiversity”
throughout Questions 6.08 and 6.09 should be understood in a broad sense,
38
i.e. it should also include species that have been naturalised for centuries and
that play an important role in the ecosystems or local cultural heritage, such
as walnut (Juglans) or chestnut (Castanea) in Europe. The assessor may also
include other, more recently introduced beneficial organisms such as exotic
plants that play a role in ecosystem services, e.g. plants used against erosion.
Note 2: If possible, all mechanisms of impact on native biodiversity should be
considered, but only the mechanism providing the highest score and lowest
uncertainty is kept for the scoring of the indicators. Mechanisms of impact
may include, among others:
Competition with native vegetation for limiting resources: Invasive plants are,
simply by occupying a large amount of space in invaded habitats, expected to
impose a significant impact on the native vegetation through competition for
space, light, water and nutrients. For example, the tall and densely growing
alien Fallopia species shade out native plant species.
Allelopathy: Allelopathy is defined here as a chemically mediated interference
competition between co-occurring plant species, including both direct effects
of the chemicals and indirect effects of the chemicals that are mediated by the
soil microbial community or other biota. Allelopathy is considered as an
important mechanism for the invasion success of various alien invasive
species, including Ailanthus altissima, Solidago canadensis or exotic Fallopia
species.
Impact of vegetation changes on higher trophic levels: Changes in plant
communities also alter communities at higher trophic levels. For example,
because alien Fallopia species are poorly colonized by resident invertebrate
herbivores, invasion by Fallopia species reduces diversity and productivity of
invertebrate communities, and, as a consequence, the fitness and density of
vertebrates that rely on invertebrates as food source.
Changes of ecosystem processes: Change of ecosystem patterns and
processes (as described in subquestions 6.08.03 to 6.08.06 below) may
indirectly affect native vegetation. For example, increased nitrogen availability
caused by nitrogen-fixing alien species such as Robinia pseudoacacia and
Acacia may reduce the competitive performance of local plants and favour
others. Also, changes in fire regime and pollination services may have serious
impacts on native community structures. Physical and chemical modifications
of habitats may also have an impact on invertebrate and microbial soil
communities.
Disease vector: Alien plants can act as a vector of plant diseases affecting
native vegetation. For example, in Europe, the sudden oak death
Phythophtora ramorum is spread mainly by the trade of exotic ornamentals
such as Viburnum spp. and Rhododendron spp.
Pesticide use: An intensive use of non-specific pesticides over wide areas
may affect native biodiversity, in particular when used in natural or semi-
39
natural habitats (e.g. forests, wetlands). For example, glyphosate used to
control invasive Fallopia spp. has lethal effects on amphibians.
Hybridization: Hybridization between an alien and a native species or subspecies may affect the genetic integrity of native species or sub-species. For
example, the Spanish Bluebell Hyacinthoides hispanicus successfully
hybridizes with the native bluebell Hyacinthoides non-scripta in the UK
6.08.01. To what extent does the plant cause a decline in native species
populations and changes in communities of native species?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
The decline in native species populations and changes in the
composition and structure of the communities of native species has
been studied but not observed. If no study has been carried out to
determine the level of impact, according to the information available
on the invasion status and bio-ecological characteristics of the plant
as well as on the characteristics of the invaded habitats, a decline in
native species is unlikely. In particular it can be assumed that
species that never build large and dense populations have low
impacts on native species.
Examples: Oxalis stricta is found in disturbed or man-made habitats
without making dense populations, suggesting that it has a very
limited effect on native species. Ambrosia artemisiifolia mainly
colonises bare soils and is unlikely to outcompete other plant
species. The impact of the invasive seaweed Sargassum muticum
on a low intertidal macroalgal assemblage was assessed at a rocky
shore in Spain and was found to be negligible.
Medium A decline has been observed in native species populations and/or
change in the composition and structure of the communities of
native species, but the decline or change is not persistent and is
limited in area. If no study has been carried out to determine the
level of impact, according to the information available on the
invasion status and bio-ecological characteristics of the plant as
well as on the characteristics of the invaded habitats, the impact
level is considered to be medium. In particular species that are able
to build large and dense but not persistent populations have a
medium impact on native species.
Examples: Senecio inaequidens occasionally invades semi-natural
areas in dense populations but mainly in open areas because it is a
relatively weak competitor. Azolla filiculoides forms dense
monospecific mats of floating plants that can eliminate submerged
plants and algae and reduce populations of animals beneath the
mats, but these effects tend to be transient and well localised
40
High
A decline has been observed in native species populations and/or
changes in the composition and structure of the communities of
native species, and the impact is likely to be widespread within the
habitats occupied by the species and persistent at least if no
management option is taken. If no study has been carried out to
determine the impact, according to the information available on the
invasion status and bio-ecological characteristics of the plant as
well as on the characteristics of the invaded habitats, the impact
level is considered to be high. In particular it can be assumed that
species with a known ability to build large, dense and persistent
populations have high impacts on native species.
Examples: Crassula helmsii and Ludwigia grandiflora form dense
and persistent populations in water bodies, strongly competing with
native species. Fallopia japonica produces large monopecific
populations that cause local decline of native plants. In Florida,
Melaleuca quinquenervia forms very dense stands, reducing plant
and wildlife diversity. In Australia, Mimosa pigra, by converting open
sedge wetland to shrubland, caused the loss of native plant and
animal communities. Heracleum mantegazzium reduces plant
species diversity as compared to non invaded areas in the Czech
Republic.
6.08.02. To what extent does the plant hybridize with native species?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
Hybridization with native species has been searched but has not
been observed. If no study has been carried out, then hybridization
with native species is considered to be very unlikely to occur (e.g.
no taxonomically closely-related native species occur in the invaded
region or hybridization is never observed in this taxonomic group).
Examples: There is no European congeneric species of Pueraria
lobata and, thus impact by hybridization with native species in
Europe is not possible. Prunus serotina has been present in Europe
for a long time, where many native Prunus spp. occur, but
hybridization has never been observed
Medium Hybridization with native species has been observed in the field or
in the lab, but the hybrid has a lower fitness and does not replace
the native species. If no study on hybridization has been carried out,
hybridization is considered possible because of the presence of
taxonomically closely-related species in the invaded area belonging
to genera in which hybridization has been observed.
Examples: In North America, the European Lythrum salicaria may
hybridize with the local L. alatum and, although pollen transfer result
in much lower seed set than conspecific pollination, this may still
41
have an effect on populations on the native species.
High
Hybridization with native species has been observed in the field and
the hybrid has a high fitness and is replacing, or is able to replace
the native species.
Examples: Very successful hybrids include, for example, Spartina
alterniflora X S. foliosa in the San Francisco bay or Hyacintoides
hispanica X H. non-scripta. The hybrid Populus x canadensis
threatens Populus nigra. The European shrub Crataegus
monogyna, naturalized in Canada, causes abortion of 97% ovules
of native Crataegus punctata by fertilizing with its own pollen, hence
drastically reducing seed set of the native species. the Spanish
Bluebell Hyacinthoides hispanicus successfully hybridizes with the
native bluebell Hyacinthoides non-scripta in the UK,
Alteration of ecosystem patterns and processes
Note: Only the impact on natural or semi-natural habitats should be
considered when assessing the impact on ecosystem processes and patterns.
However, natural and semi-natural habitats have to be considered in a broad
sense, i.e. every habitat that is not under constant human management. It
includes all EUNIS habitat types 1 (http://eunis.eea.europa.eu/habitats-codebrowser.jsp), except I (Regularly or recently cultivated agricultural,
horticultural and domestic habitats) and J (Constructed, industrial and other
artificial habitats). For example, grasslands that are regularly mown are
included as well, but not those that are repeatedly re-seeded.
6.08.03. To what extent does the plant cause physical modifications of
habitats (e.g. changes to the hydrology, significant increase of water turbidity,
light interception, alteration of river banks, changes in fire regime, etc.)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
The physical modification of habitats has been studied but not
observed. If no study has been carried out to assess the impact,
according to the information available on the invasion status and
bio-ecological characteristics of the plant as well as on the
characteristics of the invaded habitats, a physical modification of
habitats is unlikely.
Examples: Ambrosia artemisiifolia is very unlikely to cause physical
modification of habitats.
Medium A physical modification of habitats has been observed but the
impact is not persistent and limited in area. If no study has been
carried out to assess the impact, according to the information
42
available on the invasion status and bio-ecological characteristics of
the plant as well as on the characteristics of the invaded habitats,
the impact level is considered to be medium.
Examples: Azolla filiculoides forms dense monospecific mats of
floating plants that reduce light interception and photosynthesis for
submerged plants. However, these dense populations tend to be
transient and well localised.
High
A physical modification of habitats has been observed and the
impact is likely to be widespread within the ecosystem where the
species is present and persistent if no management option is
undertaken. If no study has been carried out to assess the impact,
according to the information available on the invasion status and
bio-ecological characteristics of the plant as well as on the
characteristics of the invaded habitats, the impact level is
considered to be high.
Examples: Eichhornia crassipes blocks waterways. Hydrocotyle
ranunculoides alters the physic-chemical properties of water.
Fallopia japonica causes erosion of river banks.
6.08.04. To what extent does the plant cause changes to nutrient cycling
and availability (e.g. significant changes in nutrient pools in topsoils or
in water)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Changes in nutrient cycling have been studied but not observed. If
Low
no study has been carried out to assess the impact, according to
the information available on the invasion status and bio-ecological
characteristics of the plant as well as on the characteristics of the
invaded habitats, a change in nutrient cycling is unlikely.
Examples: Oxalis stricta is found in disturbed or man-made habitats
without making dense populations, and, thus, it is unlikely to change
nutrient cycles and availability in semi-natural ecosystems.
Medium Changes in nutrient cycling have been observed but the impact is
not persistent and limited in area. If no study has been carried out to
assess the impact, according to the information available on the
invasion status and bio-ecological characteristics of the plant as
well as on the characteristics of the invaded habitats, the impact
level is considered to be medium.
Examples: Lemna spp. may temporarily modify water nutrients.
Azolla filiculoides can form dense floating monospecific mats at the
surface of water bodies that reduce gas exchanges, causing the
43
predominance of respiratory activities and the reduction in dissolved
oxygen in water beneath the mats. However, these dense
populations tend to be transient and well localised.
High
Changes in nutrient cycling have been observed and the impact is
likely to be widespread within the ecosystem where the species is
present and persistent if no management option is undertaken. If no
study has been carried out to assess the impact, according to the
information available on the invasion status and bio-ecological
characteristics of the plant as well as on the characteristics of the
invaded habitats, the impact level is considered to be high.
Examples: Robinia pseudoacacia, Acacia spp. and Lupinus
polyphyllus increase nitrogen soil content. Carpobrutus spp. modify
soil organic contents because of low decomposition rate. Invasive
nitrogen-fixing plants and trees that produce dominant populations
are likely to score high.
6.08.05. To what extent does the plant cause modifications of natural
successions (e.g. acceleration or temporary freezing of successions)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
A modification of natural successions has been studied but not
observed. If no study has been carried out to assess the impact,
according to the information available on the invasion status and
bio-ecological characteristics of the plant as well as on the
characteristics of the invaded habitats, a modification of natural
successions is unlikely.
Examples: Ambrosia artemisiifolia rarely establishes in natural plant
communities, except on bare soil. Therefore, it is highly unlikely that
it will modify natural successions.
Medium A modification of natural successions has been observed but the
impact is not persistent and limited in area. If no study has been
carried out to assess the impact, according to the information
available on the invasion status and bio-ecological characteristics of
the plant as well as on the characteristics of the invaded habitats,
the impact level is considered to be medium.
Examples: In Central Europe, Acer negundo is a competitive
pioneer plant but it is usually replaced in the course of succession
by more shade-tolerant species.
High
A modification of natural successions has been observed and the
impact is likely to be widespread within the ecosystem where the
species is present and persistent if no management option is
44
undertaken. If no study has been carried out to assess the impact,
according to available information on the invasion status and bioecological characteristics of the plant as well as on the
characteristics of the invaded habitats, the impact level is
considered to be high.
Examples: Prunus serotina and Rhododendron ponticum impede
the natural rejuvenation of forest trees. Buddleja davidii and Robinia
pseudoacacia are highly competitive pioneer plants in their invasive
range. They hamper habitat recolonisation by native trees and
shrubs.
6.08.06. To what extent does the plant disrupt trophic and mutualistic
interactions (e.g. through the alteration of pollinator visitations - leading to a
decrease in the reproductive success of native species-, allelopathic
interactions, strong reduction of phytophagous or saprophagous communities,
etc.)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
A disruption of trophic and mutualistic interactions has been studied
but not observed. If no study has been carried out to assess the
impact, according to the information available on the invasion status
and bio-ecological characteristics of the plant as well as on the
characteristics of the invaded habitats, a disruption of trophic and
mutualistic interactions is unlikely.
Examples: Akebia quinata is poorly attacked by herbivores in
Europe, does not have closely related plant species in Europe,
reproduces mainly vegetatively and never produces dominant
stands. Therefore, it is very unlikely that it significantly disrupt
trophic and mutualistic interactions.
Medium A disruption of trophic and mutualistic interactions has been
observed but the impact is not persistent and limited in area. If no
study has been carried out to assess the impact, according to the
information available on the invasion status and bio-ecological
characteristics of the plant as well as on the characteristics of the
invaded habitats, the impact level is considered to be medium.
Examples: In Spain, Opuntia spp. modify the number of links
between plants and pollinators but the effect on native pollination
network properties is limited.
High
A disruption of trophic and mutualistic interactions has been
observed and the impact is likely to be widespread within the
ecosystem where the species is present and persistent if no
management option is undertaken. If no study has been carried out
45
to assess the impact, according to the information available on the
invasion status and bio-ecological characteristics of the plant as
well as on the characteristics of the invaded habitats, the impact
level is considered to be high.
Examples: In Florida, Melaleuca quinquenervia has replaced
sawgrass marshes and other vegetation types, dramatically
changing the food web of these ecosystems. Rhododendron
ponticum’s poor quality
litter and densely shaded canopy suppresses decomposition rates
and algal production in invaded streams in UK, as well as the
availability of resources to consumer assemblages. In North
America, the high abundance of the European Lythrum salicaria
disrupts pollination of local plant species by pollinators, affecting
seed production of the native species.
Conservation impacts
6.08.07. To what extent does the plant occur in habitats of high
conservation value (includes all officially protected nature conservation
habitats)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
The plant occurs exclusively, or nearly exclusively, outside habitats
of high conservation value
Examples: Oxalis stricta and Setaria verticillata are usually found in
disturbed or man-made habitats.
Medium The plant occurs only occasionally in habitats of high conservation
value or, if it occurs regularly, its competitive effects on native
species are moderate in such habitats.
Examples: Solidago gigantea only occasionally colonizes high
conservation value habitats. Amelanchier lamarckii is found in some
high conservation value habitats, but without making dense
populations, thus most probably having a moderate impact in such
habitats.
High
The plant occurs regularly in habitats of high conservation value
and it competes, or is likely to compete successfully with native
species in such habitats.
Examples: Carpobrutus spp. and Rosa rugosa form high
populations in dune ecosystems of high conservation value,
competing with native species in such habitats. Ludwigia grandifolia
often colonizes water bodies of high conservation value and form
dense populations, impacting the native fauna and flora.
46
6.08.08. To what extent does the plant threaten rare or vulnerable
species (includes all species classified as rare, vulnerable or endangered in
official national or regional lists within the PRA area)?
Level
uncertainty:
of Low
Medium
Low, Medium, High
High
Rating guidance
Low
The plant has no impact on survival or reproduction of rare or
vulnerable native species in the susceptible habitats.
Examples: Ambrosia artemisiifolia rarely establishes in natural plant
comunities and does not represents a threat to rare or vulnerable
species
Medium The plant interferes with native rare or vulnerable species resident
in the susceptible habitats and may cause a limited population
decline of these rare or vulnerable species, but there is no sign that
the decline may lead to local extinction.
Examples: In North America, Lythrum salicaria interferes with the
rare Sidalcea hendersonii but the native plant persists in invaded
areas.
High
The plant directly or indirectly threatens the survival or reproduction
of native rare or vulnerable species resident in the susceptible
habitats, which may lead to local extinction.
Examples: In dunes of the North American Pacific coast the
European Ammophila arrenaria eliminates rare species such as
Oenothera deltoides ssp. bowellii and Erysimum menziesii ssp.
Menziesii. Carpobrotus spp. outcompete 27 taxa with a high
patrimonial value in Provence (France).
Final rating:
- Each of the three impact categories will be scored with the highest
indicator score within its category
- A final rating is obtained as follows:
• Massive: 3 x High
• Major: 2 x High and 1 x Medium
• Moderate: 1 x High and at least 1 x Medium or 2 x High and 1 x Low
• Minor: 1 x High and 2 Low or 2 or 3 x Medium
• Minimal: Maximum 1 x Medium, all others Low
47
Q6.09: How important is the environmental impact likely to be in the PRA
area?
Minimal, minor, moderate, major, massive
Verify that, based on Q5.08, an environmental impact is also likely to occur in
the PRA area, and, if yes, at a comparable level, using the following
questions. For this, answers to the section in the “likelihood of establishment”
section should be taken into account:
6.09.0A Taking into account the responses to the relevant questions (on
hosts and habitats, climatic conditions, abiotic factors, management
methods) in the establishment section, are the conditions in the PRA
area sufficiently similar to those in the area of invasion to expect a
similar level of impact?
If No: the situation regarding environmental impact may be different, the
assessor should use the subquestions in Q6.08 and reassess those
subquestions concerned by the differences identified between the
invaded and the PRA areas.
If Yes: Go to next question (6.09.0B)
Level
uncertainty:
of Low
Medium
High
6.09.0B Does the same native species or community, or the same
threatened ecosystem services, occur in the PRA area and, if not, is it
known whether the native species or communities, or ecosystem service
in the PRA area are similarly susceptible?
If No: the situation regarding environmental impact is likely to be
different between the invaded and the PRA areas, the assessor should
use the subquestions in Q6.08 and reassess those subquestions
concerned by the differences identified between the invaded and the
PRA areas.
If Yes: The situation regarding environmental impact is likely to be
similar between the invaded and the PRA areas, the score of Q 6.08 can
be given in Q 6.09 as impact elsewhere will be the most reliable criterion
to predict the impact in the PRA area.
Level
uncertainty:
of Low
Medium
High
6.09.0C If the assessor considered that Q6.08 has could not be
answered, i.e. the species has not invaded any other area, or if the
invasion is too recent and too little is known on its ecology in the
invaded areas, and assuming that no additional investigations can be
undertaken during the time available for producing the PRA, an
environmental impact assessment cannot be properly made using this
scheme. Nevertheless, in any case, the assessor should be able to provide
his/her opinion on the potential environmental impact in the PRA area.
48
Note: So far PRAs carried out for plants in Europe have only concerned plants
that have already been reported to be highly invasive or to have an impact,
i.e. plants for which Q6.08 can definitely be answered. However, in the future,
PRAs may be done for species that are just escaping from cultivation and
have no invasion and impact history (e.g. Acer rufinerve in Belgium). To
assess these particular cases, an additional set of questions or even another
assessment approach may be needed.
49
7
Scoring systems for additional effects and conclusion
As noted in the introduction, the evaluation of the following questions may not
be necessary if the responses to question 6.04 and 6.05 are "major" or
"massive" or any of the responses to questions 6.06, 6.09 and 6.11 is “major"
or "massive” or "very likely" or "certain", and you can go to 6.16 unless a
detailed study is required or the answers given to these questions have a high
level of uncertainty. The previous questions about additional effects (2.11) has
been incorporated in question 6.02.
Old question: 2.12 How likely are control measures to disrupt existing
biological or integrated systems for control of other pests or to have negative
effects on the environment?
impossible, very unlikely, unlikely, moderately likely, likely, very likely, certain
Level
of Low
Medium
High
uncertainty:
New Question 6.12 To what extent is the pest likely to disrupt existing
biological or integrated systems for control of other pests?
Minimal extent, minor extent, moderate extent, major extent, massive
extent
Level
of Low
Medium
High
uncertainty:
Old question 2.13 How important would other costs resulting from introduction
be?
Note: costs to the government, such as project management
and
administration,
enforcement,
research,
extension/education, advice, publicity, certification schemes;
costs to the crop protection industry.
minimal, minor, moderate, major, massive
Level
of Low
Medium
High
uncertainty:
New Question 6.13 How great an increase in other costs resulting from
introduction is likely to occur??
Note: This is evaluated in comparison with total production
costs, see q. 5.05. Other costs include costs to the
government, such as project management and administration,
enforcement, research, extension/education, advice, publicity,
certification schemes; costs to the crop protection industry.
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
Rating guidance:
50
Minimal: no increase of costs expected.
Minor: other costs are negligible.
Moderate: other costs are limited but cannot be neglected.
Major: other costs are substantial.
Massive: other costs are very expensive.
Old question 2.14 How likely is it that genetic traits can be carried to other
species, modifying their genetic nature and making them more serious plant
pests?
impossible, very unlikely, unlikely, moderately likely, likely, very likely, certain
Level
of Low
Medium
High
uncertainty:
Old question 2.15 How likely is the pest to cause a significant increase in the
economic impact of other pests by acting as a vector or host for these pests?
Impossible/very unlikely, unlikely, moderately likely, likely, very likely/certain
Level
of Low
Medium
High
uncertainty:
6.14 How great an increase in the economic impact of other pests is
likely to occur if the pest can act as a vector or host for these pests or if
genetic traits can be carried to other species, modifying their genetic
nature?
Level
uncertainty:
of Low
minimal, minor, moderate, major, massive
Medium
High
Rating guidance:
Minimal: no increase of costs expected.
Minor: other costs are negligible.
Moderate: other costs are limited but cannot be neglected.
Major: other costs are substantial.
Massive: other costs are very expensive.
Conclusion of the assessment of economic consequences
6.15 With reference to the area of potential establishment identified in Q
3.08, identify the areas which are at highest risk from economic,
environmental and social impacts. Summarize the impacts and indicate
how these may change in future.
minimal, minor, moderate, major, massive
Level
uncertainty:
of Low
Medium
High
51
References
EPPO (2008) Eichhornia crassipes. EPPO Bulletin 38, 441-449.
DEFRA (2005) UK Non-native organism risk assessment scheme, user
manual.
A. Ricciardi & J. Cohen (2007) The invasiveness of an introduced species
does not predict its impact. Biological Invasions 9, 309-315.
J. Bremmer, T. Soliman, M. Kenis, U. Schaffner, M. Mourits, W. v. d. Werf &
A. G. J. M. Oude Lansink (2009) Review of impact assessment methods
for pest risk analysis. LEI, The Hague.
52
Annex 1 Matrix model for qualitative economic impact
assessment
The matrix model combines the answers of the questions about economic
impact assessment pairwise. The maximum rule is applied which means that
the higher risk rating from the two questions is taken when combined .
Whether questions 6.12, 6.13 and 6.14 are answered depends on the
answers to the questions 6.06, 6.09 and 6.11 are major or massive.
53
Annex 2 Decision tree to classify products on the basis of
yield fluctuations
Is the crop grown
under protected
cultivation?
yes
Yield variation is low
no
Are the products
sold per number
(high quality
products) or per
kg (bulk
)products)?
high
quality
.
yes
bulk
Does the
production
process take more
than one year?
Is the product a
fruit?
no
no
Yield variation is high
yes
Yield variation is moderate
54
Annex 3 Decision tree for indirect effects
Introduction
The qualitative economic impact assessment scheme as presented in
Hammamet focuses on the direct impacts to producers (Questions 5.01-5.05),
the consequences of an export ban (Question 5.06) and the extent to which
direct losses can be borne by producers. One question (5.07a) assesses the
potential effects on consumers. However, there is still a need for more
guidance to make the indirect effects more explicit and easier to assess.
In most cases of major or massive direct economic impacts, indirect effects
will occur. Farmers and growers will try to compensate for their losses, either
to other producers or to customers or both. Even in cases when farmers are
able to transfer most of the losses to others, this does not necessarily mean
that the other parties suffer substantial losses. This depends on a number of
factors:
1.
If producers shift to growing alternative products, it is important to
consider the size of both the infested and the alternative market. In most
cases, farmers tend to grow products with a comparable added value per ha,
and which can be grown without large investment. A shift to products with a
higher added value per ha can have large consequences for existing growers
of this product. However the acreage of products with a high added value is
lower than the area of products with a low added value. For example, an
arable farmer who converts 10 ha potatoes to 10 ha bulbs is likely to cause
much more trouble to other bulb growers through competition than vice versa.
However, in most cases, arable growers include other arable products and
bulb growers include other bulb products in their rotation.
2.
If producers are able to transfer a large proportion of the impacts to
consumers, in only a limited number of cases, consumers will experience
higher prices and a reduced availability of the product. Products with a low
consumer responsiveness are mostly bulk goods, which are grown at a large
scale, such as potatoes, cereals, maize etc. If these products are only
affected in a certain area, the product can be imported from other countries. In
some cases an import ban will be opposed to prevent the mixture of healthy
imported products with infested domestic products. A (potential) example is
the market for wood products in Portugal threatened by the Pinewood
Nematode. A combination of an export ban and an import ban in the same
country will totally separate internal and external markets. If there are
substantial export or import volumes (compared to domestic production),
consumers are likely to experience changes in prices. However, this will only
occur in very exceptional cases.
Products with a higher added value normally have higher consumer
responsiveness. This is partly because these products are relatively more of a
luxury which implies that consumption can be postponed and partly because
consumers have the opportunity to shift to alternative products (carnations
instead off roses). Consumers are therefore more vulnerable when niche
market products are affected. These products include those which are grown
at a limited scale for special purposes: flowers for funerals, plants grown for
medical purposes etc.
55
The following aspects need to be addressed in the decision tree:
- Type of indirect effect. Two types can be distinguished: effects on
producers in the same agricultural/horticultural sector and effects on
consumers. It must be noted that the PRATIQUE quantitative economic
impact assessment model only assesses the effects on consumers.
This is inherent to the chosen methodology, partial equilibrium
modelling, which only estimates changes in supply, demand and prices
of the product at risk.
- Magnitude. It is important to distinguish between the extent to which
affected producers are able to compensate for direct effects and the
extent to which other groups involved (either producers or consumers)
experience negative impacts. It is possible that even if a substantial
part of a massive impact can be borne by producers or consumers, the
size of this group may be so large that individual producers and
consumers do not experience any significant change on product prices.
The proposed decision tree is presented in Figure 1 and has the following
structure:
1. The decision tree starts with a question that determines whether an
analysis of indirect impacts is appropriate. The criterion is that the net
short term economic impacts caused by yield losses, additional
production costs or an export ban should at least be major.
2. The second aspect to consider is the short term economic effect of an
export ban when products at risk may be sold in the domestic market
leading to lower prices. A drop in prices can be reduced if alternative
markets for the crop are available. If this is not the case, producers will
look for alternative products to grow.
3. The third aspect takes into account consumer responsiveness (also
known as consumer price elasticity). If consumer responsiveness is
low, e.g. for staple crops like potatoes, consumers accept higher
prices, do not shift to alternative products or postpone consumption
and the impacts are mainly borne by consumers. A low consumer price
elasticity implies that, if the price increases by more than 1%, the
supply will decrease by 1%. For products with a low consumer price
elasticity, the price increases will only be experienced by consumers of
niche market products and not in other cases.
4. The fourth aspect deals with the possibility for producers to shift to
other products. The ease with which production can be adjusted
depends on:
a. the time needed for new crops to reach full production, e.g. one
season for potatoes and several years for apples and
b. the availability of factors such as labour, land and the investment
(in plants for planting, buildings such as glasshouses etc.) which
may have to be made to increase production.
The decision to shift to other products also depends on factors such as market
expectations and the potential for storage of the product until prices rise.
Shifting to other crops is easiest in production sectors where several crops are
grown in rotation, e.g. arable farming and nursery stock.
56
Examples
Drosophila suzukii can cause massive damage to a number of fruit crop crops
such as strawberries, raspberries, cherries etc. By applying the decision tree it
is clear that this will have indirect impacts. The net economic short term effect
is not caused by an export ban. If only a single soft fruit crop would have been
affected, consumers could shift to other soft fruits assuming they are available
at the same time of year and are equally liked. However, with D. suzukii many
soft fruit crops are affected. Therefore consumers have almost no possibility
to shift to other products, but they can postpone consumption or decide not to
consume it. The question ‘Do consumers have possibilities to use alternatives
or to postpone consumption?’ cannot be answered with a clear ‘yes’ or ‘no’. In
the case this question is answered with ‘no’, the result is that the consumers
mainly bear the indirect impacts. Because this pest is a severe threat, it is
likely that prices will increase. If the question is answered with a ‘yes’, the
result is that the direct impacts will mainly be borne by the affected producers.
Soft fruit production takes more than one year, so shifting to alternatives takes
a long period. According to the rating guidance, question 5.07 gets the score
‘moderate’.
Xanthomonas axonopodis pv. allii causes major damage to Allium crops
(onions). The decision tree can be applied. An export ban is not likely; the
economic impact is mainly caused by the damage to the crop itself.
Consumers will not use alternatives or postpone consumption. It is not a niche
market product. Therefore, it is likely that economic impacts will mainly be
borne by consumers. Whether they will experience price effects depends on
the yield loss per ha and the size of the affected area compared with the total
production area worldwide. According to the rating guidance, the answer to
question 5.07 will be rated as ‘minor’.
Meloidogyne enterolobii is expected to cause major damage to a wide range
of host plants in different families. This complicates the application of the
decision tree. Nevertheless, it is clear that the economic impact is not caused
by an export ban. The question whether consumers have the possibility to
shift to alternatives or to postpone consumption has to be answered for a
range of products simultaneously. It is likely that the possibilities are limited.
Products are predominantly not niche market products. It is therefore likely
that consumers will bear a large part of the economic impact and will
experience higher prices. Question 5.07 can be rated ‘minor/ moderate’. M.
enterolobii is a polyphagous nematode and and important crop pest that can
cause substantially yield losses. It is likely that the higher prices can partly
compensate for yield losses.
57
Fig. 1. Decision tree to determine who experiences indirect economic impacts.
Is the net economic
short term effect
major or massive?
no
Analysis of indirect impacts
not necessary
yes
Is an alternative use
of the product
possible?
no
yes
Is the net economic
short term mainly
caused by an export
ban?
Impacts mainly borne by
consumers, but price effects will
be experienced in severe cases
yes
no
no
No large indirect effects
Do consumers have
possibilities to use
alternatives or to
postpone
consumption?
no
Is the product at risk
a niche market
product?
yes
Does the producer
have possibilities to
shift to alternative
products?
yes
Impacts mainly be borne by
consumers, and price effects
will be experienced
no
yes
Impacts mainly borne by
producers in the same sector
Impacts mainly borne by
affected producers
58