Deer Overabundance is Impacting Biodiversity in Parks Located in Fairfax County, Virginia. Sean...
Transcript of Deer Overabundance is Impacting Biodiversity in Parks Located in Fairfax County, Virginia. Sean...
Deer Overabundance is Impacting Biodiversity in Parks Located in Fairfax
County, Virginia.
Sean Campbell, Tammy Henry, Megan Scott,
Craig Shafer, and Jessica Trice
Overabundance of Deer
Animals are Overabundant* when:a) threaten human life or livelihoodb) are too numerous for their “own good”c) depress the densities of economically
or aesthically important speciesd) cause ecosystem dysfunction
0
5
10
15
20
25
30
1900 1990 2000
white taileddeerpopulation
100 Years of Deer in United States Deer are Reproductive Machines
*Caughley (1981)
Impacts of an Overabundance of Deer
• Automobile Damage>1100 deer collected ~ 20% deer collisions
Average collision cost = $2300
7th highest rate of deer collision in the country
• Change to Forest Structure - Regeneration Patterns
• Disease: Human & AnimalLyme Disease & Others
Hemorrhagic Disease & Chronic Wasting Disease
• Ornamental Plant Damage• Biodiversity:
– Animals– Plants
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Causal Links:
People
Predators Hunting
Development
Fragmentation
PlantsAnimalsBiodiversity
DeerOverabundance
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
AutoCollision
Disease
Carrying Capacity Theory (Caughley)Ecological Carrying Capacity (K)
Maximum Sustainable Yield (MSY) Economic Carrying Capacity (I)
Sociological Carrying Capacity (Cultural)
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.
Deer Carrying Capacity & Vegetation
Factors:
1. Plant biomass Environment
2. Rate of Plant Intake/Animal Density
of Plants
3. Rate of Population ∆ of deer Density
of Plants
Impacts on Biodiversity
- Browse-line shows degree of deer impact
- Changes forest structure (impacts on birds and invertebrates)
- Reduced habitat for ground-nesting animals, decreased food sources, affects on plant reproduction
- Reduced tree regeneration & decreased diversity in regrowth
- Increased ability for invasive/exotic species to establish QuickTime™ and a
TIFF (Uncompressed) decompressorare needed to see this picture.
Criteria
1. Socially and Ethically Acceptable2. Economically Feasible3. Sustainable4. Efficient5. Quantifiable/Accountable Results6. Ecologically Sound7. Proven Methodology
Potential Solutions:• Ignore the problem• Reduce human population - relocation or birth
control• Unpalatable plants - naturally or chemically treated• Visible or audible deterrents • Prevent future land use changes (ie. development)• Corridors/underpasses for deer• Reintroduce predators (wolf, black bear, puma &
bobcat)• Immunocontraception• Fence deer in/out - physical or shock/alarm collars• Relocate deer• Change Fairfax County hunting regulations• Managed reduction - snipers or recreational hunting
Evaluating the criteria…
Managed reduction - snipers or recreational hunting
Meets all 7 criteria: socially acceptable, economic, sustainable, efficient, accountable, ecologically sound, & proven
Plan: multifaceted hunting approach• Police Force• Consulting Firm• Recreational Hunters
Reducing the deer population will lead to an increase in biodiversity - both in plants & animals.
Positive Results of an Appropriately Managed Deer
Population• Larger healthier deerLarger healthier deer• Improving habitat Improving habitat • Conserving biodiversityConserving biodiversity• Increased Environmental/Educational Increased Environmental/Educational
OpportunitiesOpportunities• Economic benefitsEconomic benefits• Provides food/sustenance Provides food/sustenance • Decreased human/wildlife conflictDecreased human/wildlife conflict• Cultural Traditions/Recreational Cultural Traditions/Recreational
OpportunitiesOpportunities• Funds raised to contribute to other Funds raised to contribute to other
wildlife management effortswildlife management efforts
Fairfax County Parks:
Huntley Meadows
Pohick Bay
NEXT: Application of Deer Management Strategy in Fairfax
County, VA
• Fairfax County Deer Management Plan
• Comparison of Huntley Meadows & Pohick Bay
• Recommendation to Hemlock Overlook
Huntley Meadows - sharpshooting, managed hunts
(shotgun & archery)
Pohick Bay - no planned reductions
QuickTime™ and aTIFF (Uncompressed) decompressor
are needed to see this picture.QuickTime™ and a
TIFF (Uncompressed) decompressorare needed to see this picture.
Questions?