Transcript Predator Management- Here We Go Again?

Predators, Predation, &
Predator Control
Bruce D. Leopold, Mississippi State University
Historical Perspective
•
“Harmony with the land is like harmony with a friend, you cannot
cherish his right hand and chop off his left. That is to say, you can’t
love game and hate predators, the land is one organism.”
Historical Perspective
Predator Control Under Scrutiny
• Leopold Report (A. Starker)- 1964
• Cain Report - 1972
• Nixon (by Executive Order) stopped use of
all poisons on federal lands or use by
federal agencies to control predators
Trends Regarding
Furbearing Predators
Possible Effects????
Before History Repeats Itself
?
Predators- Their Value
• A natural component of the ecosystem, often
aiding in maintaining stability
• Often remove sick and injured individuals from
the population
• Serve to keep animals “wild and wary”
• Often regulate prey populations, many of these
prey populations are equally harmful to game
animals
• Are valuable as sport animals
Predators- Societal Values
Survey of 1500 households
•
•
•
•
•
•
have a right to exist
should be reintroduced to former ranges
do need to be managed, but with conditions
should not be hunted or trapped unconditionally
are not the cause of game population declines
play an important role to maintain balanced
natural systems
• ==> They do support predator management!!!
Before Biologists “Jump into”
Predator Control, They Need to
Consider Many Factors
Prey
Predator
Animal Welfare Issues
• Animal Welfare Act & Amendments
– Recently to include birds and rodents
• University IACUCs
• Federal Funds and State Agencies (PR & DJ)
• Initiatives to stop trapping and hunting
Must Be Careful of the Message
• Kill predators so that we have more game to
harvest
• NWTF- Resolution- Not to Use Predator
Control to enhance single species
• SE Section TWS- Resolution- Not to Use
Predator Control to enhance single species
Management activities conducive
to predators
•
•
•
•
Logging roads/Access roads = Travel Corridors
Food plots =Concentrating prey & Predictability
Maintain early successional stages = Food base
Small management units = Increased efficiency
Identifying the True “Culprit”
Decimating versus Limiting Factors
Nest Losses
• Massachusetts- 22%
• Alabama: 85%
• Kentucky: 1975- 55%
1978- 80%
• Texas: 1972- 61%
1980- 56%
1987- 100%
Prey Adaptations- Coevolution
The Wild Turkey
•
•
•
•
•
•
•
Large body size
Long-lived
Roost in trees
Form flocks
Large clutch sizes
Prefer open habitats
Hen moves great distances when disturbed
120
100
80
60
40
20
With Predator
Control
Without Predator
Control
0
0 1 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95100
Density-dependent Responses
Study in Texas and Coyote
• With intensive control: litter size- 6.56
• With no control: litter size- 3.65
• Well nourished coyote- from 10-12 pups
Interactions
• Coyote in Texas- w/ control, less rodent
richness and diversity
• In SE US, coyote versus red fox
• Prairie- wolf versus meso-carnivores
(raccoons, fox, skunk)
Predator Control
When is it warranted?
The Wildlife Society
• When introducing a species to former habitat
• Endangered/threatened species
• Man-induced disruption
Problems identified with Predator
Control
• Coyote- requires 75% reduction in population to
observe a change in population status
• Must be intensive first 3-4 years
• Can not stop
• Can not be haphazard
• Not cost-effective
Past Research Results
Predator control will enhance game
populations
•
•
•
•
•
White-tailed deer
Wild turkey
Pheasant
Waterfowl
Northern bobwhite
Problem is: in every study, cost of the “extra” animals
was excessive
Possible solutions
Habitat manipulations
• Pronghorn and Coyote- Utah
• White-tailed deer and Coyote- Texas
Protocol for Predator Control
• What are the management goals and thus management objectives
for the prey (game animal)? Are they reasonable and biologically
sound?
• Has predation been identified as the ultimate mortality factor rather
than a proximate factor?
• Has the predator species been identified correctly? Has appropriate
Aevidence@ been collected and reliably identified (tracks, photos,
sign on carcasses or eggs, etc.)
• Have extrinsic, contributing factors been examined throughly
(habitat conditions, weather effects, land management activities)
that may have, on the short-time, caused an imbalance in predator
and/or prey species abundance(s)?
• Has the target predator species role within the system been
evaluated thoroughly to ensure that the control operation may not
further disrupt existing balances?
Protocol for Predator Control
• Have alternatives to active predator removal been examined based
on evaluation conducted previously?
– can habitat manipulation achieve desired goals?
– can subtle changes in current land management be implemented?
– can more “desirable” predator species be enhanced to counter “more
detrimental species”? [Note: enhanced can simply mean to cease trapping that
predator species (e.g., coyote versus red fox)]
• Clearly define the objectives of the predator management program
– What is the desired population response (e.g., density) of the prey (game
animal)?
– What is the desired percentage reduction in the target predator population?
– What monitoring program(s) will be implemented to monitor response of prey species
and target predator species?
Protocol for Predator Control
• Ensure that Best Management Practices (BMPs) for trapping (based
on draft BMPs under development) are adhered to. These include
–
–
–
–
appropriate traps that minimize injury to animal,
appropriate frequency of trap-line checking,
maintaining a trap-line size consistent with available resources,
capture of non-target species is monitored and minimized. If excessive,
trapping procedures should be reevaluated and modified, and
– appropriate euthanasia procedure(s) for animals are implemented.
• Have societal beliefs (especially local and regional) been examined
and considered?
– if potential problems are identified, develop a concise response that provides
empirically-based data, program objectives, and target species.
– all staff should provide a consistent response when inquiries are made about
the predator management program, or inquires should be redirected to one
individual
Protocol for Predator Control
• Inappropriate behavior by staff should not be tolerated.
Deviation from selected harvesting protocols and
objectives should be stopped immediately.
• Carcasses should be disposed of discretely or used
appropriately (food, museum displays, etc.).
Questions??