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Analysis of environmental risks:
How to assess and manage risks of
invasive alien species harmful to
plants?
G. Schrader
Gritta
Schrader
26 October 2005
Federal Biological
Research Centre
for Agriculture
and Forestry
Federal
Biological
Research
Centre
for
Department for Plant Health, Braunschweig, Germany
Agriculture and Forestry, Department for Plant Health
Invasive alien species
A species, subspecies or lower taxon,
introduced
outside its natural past or present distribution
whose introduction and/or spread
threatens biological diversity
(according to the Guiding Principles on invasive alien
species, CBD)
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Examples for IAS in the context of plant health
• Horticultural pests
(e.g. Phytophthora ramorum)
• forest pests (e.g. Ceratocystis fagacearum on oaks;
Bursaphelenchus xylophilus on conifers)
• Indirect pests (bee parasites, e.g. Varroa
jacobsoni; earthworm predators, e.g.
Arthurdendyus triangulatus)
• Plants (weeds, invasive plants
e.g. Kudzu, Lysichiton)
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Plants as plant pests
Invasive alien plants can pose serious threats to
cultivated and wild plants
 this provides the chance to regulate them as
„plant pests“
within the framework of
the plant health
regulatory systems
IPPC and EPPO have adopted statements accordingly
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Not all alien plants have to be managed
There are many desirable alien plants, embellishing
parks, gardens, and landscapes. Only very few cause
problems, but these problems can be massive
Tens Rule:
10 % of introduced species spread,
10 % of these establish, and
10 % of the established species
cause problems (= 0,1%)
 PRA is important to identify these few species!
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Invasive alien plants in plant quarantine
Basic requirements
(according to ISPM No. 11):
Is organism a plant pest?
Indirect effects
Direct effects
Initial Effect on
Species in other
Trophic Levels
Competition
•
plant has to fulfil
definition of a pest of plants,
Direct pest
Indirect Pest
Change in
species,
communities
and ecosystems
Damage/injury to plants possible
•
•
criteria have to be clearly
documented, consistent and transparent,
„pest plant“
if invasiveness is suspected, a certain evidence
has to be demonstrated
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Guidance on PRA: Standards by IPPC and EPPO
Prevention of introduction of invasive alien species harmful
to plants or selection of adequate control strategies
if introduction could not be prevented
•
International Standard on Phytosanitary
Measures ISPM No. 11 (2004):
Pest risk analysis for quarantine pests including
analysis of environmental risks and living
modified organisms
•
G. Schrader
26 October 2005
EPPO Standards PM 5/3(1) and PM 5/4(1):
Revision: PM 5/.. (2) Guidelines on Pest Risk Analysis;
Decision-support scheme for quarantine pests
(approved by EPPO working party in June 2005)
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
PRA: Differences in the assessment of plants
• invasive plants have effects on ecosystems, habitats or
species, impacts are generally described in qualitative
rather than in quantitative terms
• unintentional introduction: seeds or other propagules
contaminating imported commodities
• intentional introduction: plants for planting, for
agricultural, horticultural or landscaping purposes
• differentiation intended/unintended habitat
• from a traditional pest, you know before that it is able
to cause damage - from a plant often not
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Unintentional introductions
•
introduced unintentionally into a country as e.g.
contaminants of seeds, bird seed, oil seed, grain,
fodder, wool, soil or other growing medium, or of
vehicles, machines or containers
•
Relevant pathways for weeds/
invasive plants to be considered and
the associated risk to be estimated
•
no intended habitat
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Intentional introductions
•
movement of the plant into a country and
subsequently into a certain area is intended
•
very important to consider pathway(s)
from intended habitat to unintended habitat
•
often promoted, that the plant establishes in the
intended habitat
•
escape into
unintended habitat
may cause
severe problems...
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Assessment of (potential) invasiveness
• Is the species invasive elsewhere?
• Is it highly adaptable to different environments?
• Does it have a broad ecological amplitude?
• Does it have a high reproduction rate?
• Are propagules highly mobile?
• Does it build up persistent seedbanks?
• Is it highly competitive?
• Does it benefit from cultivation, browsing pressure etc.?
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
More information on (potential) invasiveness
• experimental plantings (but time-lag effect
difficult to be assessed)
• surveillance after planting
• reports from other area(s) that species starts to spread
• intended use of a plant species to be taken into account
• volume and frequency of introduction of the plant into
new areas
• invasibility of relevant (intended/unintended) habitats
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Invasibility of relevant habitats
The success of a plant in invading a certain area will also
depend on the invasibility of the relevant habitats, so this
will have also to be assessed
• sites modified by man
• strongly disturbed grounds
.
• nutrient rich / poor soils (or waters)
• vegetation close to nature
• ...
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Case study: Lysichiton americanus
• intentional introduction, easily available (garden
centres, internet)
• pathway intended - unintended habitat:
intentional planting
• biotic and abiotic factors favorable for
establishment in PRA area
• in some parts of PRA area already
established and invasive
• broad climatic amplitude
(native area: California to Alaska)
• high reproduction rate
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Case study: Lysichiton americanus
• propagules highly mobile (moving long
distances by water, soil, attached to machinery)
• seeds viable in soil for at least 6 years
• highly competitive (large leaves build dense layer)
• reports from other areas about spread
• swamp woods highly invasible
(vegetation close to nature)
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Difficulties of predicting invasiveness
• certain attributes increase likelihood of invasion, but
are not in any case necessary for invasion success
• plant may have all these attributes without causing
any problems
• no known broad scientific criteria for all (potentially)
invasive plants in all relevant circumstances
• complexity of ecosystems
• variability associated with organisms, habitats,
environmental factors
• lack of data
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Consequences of establishment and spread
Direct effects or primary consequences include:
• Reduction of the abundance of keystone plant species
• Reduction of plant species that are major components of
ecosystems
• Reduction of endangered native plant species
• protection of other plant species against significant
reduction, displacement or elimination
Endangered species receive more attention than just
normal species because of their status
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Reduction of keystone species
Important keystone species in European forests:
Pinus sylvestris
• can play a critical role in
forest biocenosis
• has relationships with many
plants and animals
• affects resource availability
• is very susceptible to the pinewood nematode
Bursaphelenchus xylophilus
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Consequences of establishment and spread
Indirect effects or secondary consequences include:
• significant effects on plant communities (species richness,
biodiversity)
• significant effects on designated environmentally sensitive
areas
• significant change in ecological processes and ecosystems
(including further effects on plant species)
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Consequences of establishment and spread
Indirect effects or secondary consequences include:
• effects on man's use (e.g. tourism, hunting, fishing)
• costs of environmental restoration
• effects on human and animal health (e.g. toxicity,
allergenicity)
• effects of eradication, control or other management
measures
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Assessment of economic consequences
Consideration of "use" and "non-use" values
"Use" values:
consumptive
(e.g. fishing)
non-consumptive
(e.g. using forests for
leisure activities)
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Assessment of economic consequences
Consideration of "use" and "non-use" values
"Non-use" values:
• option value (value for use
at a later date)
• existence value (knowledge
that an element of the
environment exists)
• bequest value (knowledge
that an element of the environment
is available for future generations)
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Case study: Lysichiton americanus
Primary and secondary consequences
•
significant reduction of endangered and other species
(rare mosses, orchid-species)
• effects on plant communities and designated
environmentally sensitive areas (swamp woods are
rare habitats)
• change in ecological processes and the
structure of ecosystems, as huge leaves
build a dense layer excluding light
• use and non-use values affected:
non-consumptive, option, existence
and bequest values
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Management of (potentially) invasive alien plants
• raising of public awareness
• surveillance after planting
• preparation of control or emergency plans
• restrictions or codes of conduct on import, sale,
holding, planting
• notification before import
• restrictions on movement
• obligation to report findings
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Management of (potentially) invasive alien plants
raising of public awareness
•
explanation / illustration of risks
•
recommendations what to plant instead
•
recommendations to eliminate invasive plants
•
information of road maintenance departments etc.
•
information of garden centres
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Management of (potentially) invasive alien plants
restrictions or codes of conduct on import, sale, holding,
planting, or movement…
• required growing conditions
• authorisation of habitats
• prohibition to plant into or move to
G. Schrader
26 October 2005
-
nature conservancy areas
-
areas otherwise protected
-
areas where not yet widely spread
-
areas where under official control
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Case study: Lysichiton americanus
Trade, introduction and movement of L. americanus have
negative, irreversible environmental impacts. Without strict
prevention, more invasions are foreseeable. Proposed
measures/requirements:
•
increase public awareness of the risk posed by this plant
•
prohibition or restriction of import, sale, holding, planting
•
restrictions on/conditions for planting
•
prohibition of movement
•
obligations to report findings
•
monitoring/surveillance
•
emergency plan
•
establishment of an action plan for local eradication when the
plant is found
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Implementation
• Determination whether a plant is (potentially) invasive:
How to do an effective pre-screening?
• How to avoid unnecessary or unbalanced trade
restrictions?
• Thresholds for damage?
• Increase experience
• Collection and sharing of data, databases
• Diagnostic and taxonomic networks
• How to deal with the work load?
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany
Conclusions
PRA is a useful tool for the assessment of risks posed by
invasive alien species harmful to plants. IPPC and EPPO
standards are available for this purpose.
The experience for their application and implementation in
particular with regard to plants as pests has yet to be
increased. Abstraction from ‘traditional pests’.
PRA on environmental risks is difficult due to high levels of
complexity in ecosystems, uncertainty about threats to
biodiversity, pressure arising from globalisation etc.
PRAs including management options could provide the basis
for WTO recognised regulation of specified invasive alien
plants, including prohibition or authorisation of import,
conditions for introduction or use etc.
G. Schrader
26 October 2005
Federal Biological Research Centre for Agriculture and Forestry
Department for Plant Health, Braunschweig, Germany