Download 25. Wildlife Damage to Crops and Livestock

25. Wildlife Damage to Crops
and Livestock
AUTHORS:
SUMMARY
The Risk of Wildlife Damage (RWD) Indicator is currently being developed to gain a better understanding
of the biophysical and management factors that influence wildlife damage to agricultural products across
D. Thompson,
C. Callaghan,
L. Liggins and
T. Weins
Canada. This tool will also help us assess whether the actual risk of wildlife damage is increasing,
decreasing or remaining stable, in each province. Creation of the Risk of Wildlife Damage Indicator entails
the development of predictive models of damage risk that harness crop-yield loss data and spatial information on key factors known to influence the severity of wildlife damage, such as weather events, cropping
practices, mitigation efforts, proximity of wildlife habitat and wildlife population status. Risk models,
INDICATOR
NAME:
Risk of Wildlife
Damage Indicator
historical data and small-scale farm surveys will be used to plot recent trends in wildlife damage and
predict the changes that may occur in the trends following the adoption of damage prevention measures.
STATUS:
Currently under
development
THE ISSUE
Canadians appreciate the aesthetic, recreational,
subsistence, intrinsic and ecological values of
wildlife, and maintaining wildlife populations
is a major environmental priority in Canada
(Federal-Provincial-Territorial Task Force on the
Importance of Nature to Canadians 2000). At
the same time, there is a growing realization
that the creation of conservation areas such
as parks, wildlife management areas and forest
reserves does not provide sufficient habitat
to maintain desired wildlife populations.
Agricultural land has the most fertile soils
with the most favourable microclimates in the
country and historically has supported many
of Canada’s wildlife species. Even today, many
wildlife species continue to use farmland to
meet their needs.
Agricultural producers across Canada enjoy
living in proximity to wildlife and natural areas
and recognize the importance of wildlife as
much as other Canadians. Many of them invest
time and money to enhance wildlife habitat on
their land (Environics Research Group 2000).
However, interactions between wildlife and agricultural activities can at times result in severe
damage to agricultural products. Most wildlife
species have a benign or even beneficial effect
on agriculture (e.g. songbirds and raptors help
control pests), but the relatively few species that
feed on crops, stored feed or livestock can cause
yield losses, livestock losses and damage to farm
property. For example, deer and elk damage field
(e.g. corn, alfalfa, soybean) and horticultural
crops, as well as haystacks; waterfowl damage
various crops (e.g. wheat, barley, lentils); birds
such as starlings and blackbirds damage fruit
crops; and some carnivores kill livestock.
Wildlife damage on agricultural land is most
often caused by wildlife species that are
not at risk and may actually be abundant
(Conover 2002).
Although most producers tolerate some risk of
damage in their daily operations, the actual
level, predictability, extent and cause of wildlife
damage vary widely among the provinces, farming regions and individual farms, as well as from
year to year. In a survey conducted in 2000, 57%
of rural landowners interviewed across Canada
said that they had at some point experienced
this type of damage in their operations. Many
believe that wildlife activity and damage are on
the rise (Environics Research Group 2000).
THE INDICATOR
The Risk of Wildlife Damage Indicator will be a
tool for identifying the biophysical and management factors that influence the risk of wildlife
damage to agriculture, modelling their relationships and determining whether the risk of
damage is increasing, decreasing or remaining
static over time. This risk can be expressed as
a functional relationship between biophysical
factors (weather conditions, density and
F. Biodiversity
165
importance of each variable to the overall risk
of wildlife damage and to rank the expected
frequency of damage for a prescribed geographic
area. Independent damage occurrence data
and/or expert opinions will be used to validate
the provincial-scale results.
distribution of problem species, availability of
off-farm and on-farm habitat), management
factors (damage reduction efforts, type of
production and the use of beneficial management practices) and occurrence of damage
(Figure 25-1).
CALCULATION METHOD
LIMITATIONS
The biophysical factors influencing wildlife
damage are likely too complex and regionally
variable to be integrated into a single model
that would accurately or precisely estimate the
amount of wildlife damage expected to occur in
every region of Canada. Therefore, a series of
wildlife damage risk models will be developed
using damage data for specific wildlife classes
(e.g., waterfowl, ungulates [such as deer], and
predators) in several regions across Canada.
Spatial data on biophysical factors and data
from existing wildlife damage records or smallscale surveys of producers will be gathered to
build the models. Then, statistical analyses
will be performed to determine the relative
With this indicator, damage risk assessment
will be limited to wildlife such as ungulates,
waterfowl, and predators, which are species that
have historically been the focus of mitigation
and compensation programs and a concern for
producers and provincial wildlife managers.
Initially, the Risk of Wildlife Damage Indicator
will not address crop losses caused by invasive
species or disease transmission between livestock
and wildlife. It also will not cover crop damage
caused by insects or rodents, although they
may consume much more crop biomass than
the waterfowl or ungulates. These components
may be incorporated into a future version
of the indicator.
Figure 25-1: Conceptual model showing relationship among biophysical and management
factors influencing the risk of wildlife damage
On-Farm Habitat
Quality & Quantity
Beneficial Management
Practices (BMPs)
- Night penning livestock
- Use of guarding animals
- Border cropping
- Lure cropping
- Type of Production/
Cropping Systems
- Farm Practices
e.g. field/hedgerow management
- Lands not in production
e.g. woodlots, wetlands
Risk of Wildlife
Damage
Weather Conditions
- Late Spring/Early Fall
- Time/Amount of Precipitation
- Winter Severity
Density/Distribution of
Problem Species
- Wildlife Management Practices
- Population Demographics
- Competition, Predation & Disease
- Protected Species
Off-Farm Habitat
Quality & Quantity
- Habitat Availability
& Connectivity
- Landscape Management
- Habitat Enhancement
- Protected Areas
- Invasive Species
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Environmental Sustainability of Canadian Agriculture: Agri-Environmental Indicator Report Series—Report #2
RESULTS
This indicator is currently under development
and results are not yet available.
RESPONSE OPTIONS
behavioural and life history characteristics,
it is unlikely that any single method of damage
prevention can guarantee success. Strategies
employing several management techniques in
an integrated approach are likely to be the most
effective means of reducing damage (Ontario
Soil & Crop Improvement Association 2000).
Once this indicator comes on stream, it will aid
in assessing the effectiveness of management
strategies for reducing wildlife damage on
agriculture and increase understanding of the
factors that influence success.
Socio-economic and political factors influence
perceptions of damage and the approaches
that are adopted to deal with wildlife damage.
Consequently, strategies to reduce wildlife damage on farmland must reflect the diverse facets of
the problem and they should be grounded in a
broader economical, ecological and sociological
context (Reed 1991). In the past, widespread
REFERENCES
lethal control programs (e.g. kill permits for
Conover, M.R., 2002. Resolving Human-Wildlife
ducks, poisoning of wolves) were commonly
Conflicts: The Science of Wildlife Damage
used to reduce wildlife damage to agriculture.
Management. Lewis Publishers, Boca Raton
However, this approach became increasingly
(Florida).
unpalatable to the public, and
as societal values changed over
Environics Research Group,
time, lethal methods gradually
2000. Survey of Farmers, Ranchers
gave way to non-destructive
The Risk of Wildlife
and Rural Landowners: Attitudes
methods. Producers can now
and Behaviours Regarding Land
Damage Indicator will
lessen the susceptibility of
Stewardship. ERG, Toronto
be a tool for identifying
their farms to wildlife damage
(Ont.).
the biophysical and
through a variety of beneficial
Federal-Provincial-Territorial
farm management practices
management factors
Task Force on the Importance
such as production system
that influence the risk
of Nature to Canadians, 2000.
decisions, habitat management,
of
wildlife
damage
The Importance of Nature to
harvesting practices and
Canadians: The Economic
damage prevention measures,
to agriculture.
Significance of Nature-related
including:
Activities. Environment Canada,
• fencing or border cropping with unpalatable
Ottawa (Ont.).
crops for large ungulates;
Ontario Soil and Crop Improvement
• visual and audio scare devices or lure crops
Association, 2000. Wildlife Impact Assessment
for waterfowl;
for Ontario Agriculture. OSCIA, Guelph (Ont.).
•
the use of husbandry practices such as night
penning, calving close to farm;
•
use of fencing, buildings and guardian
animals to reduce livestock depredation
by carnivores.
Wildlife management agencies can also mitigate
the susceptibility of farmland to wildlife damage
through wildlife and habitat management
efforts, targeted lethal control of carnivores and
various prevention programs. Given the different damage-causing species and their diverse
Reed, A., 1991. “Management of Greater Snow
Geese in Relation to Crop Damage: the Need for
a Diversified and Integrated Approach”. Pages
93-100 in M. Van Roomen and J. Madsen (eds),
Waterfowl and Agriculture: Review and Future
Perspective of the Crop Damage Conflict in
Europe, proceedings of the ‘Farmers and
Waterfowl: Conflict or Coexistence’ Workshop in
Lelystad, Netherlands. Wetlands International,
Publication No. 21, Slimbridge (U.K.).
F. Biodiversity
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