- Public Menace, Audubon, National Audubon Society, July, 2005
- Here is a four-part series by the Michigan Wildlife Conservancy on the on problems that can result when there are too many deer. The first of the series gives an overview of the issues. The remaining three articles deal with impacts on specific kinds of plants and animals, and methods to control deer numbers.
New study finds zoning ineffective for deer winter habitat conservation, Phys.org, Aug 24, 2018
Weeds, worms, and deer: positive relationships among common forest understory stressors, Biological Invasions, May 2018
Without its ‘understory’ layer, the forest will collapse, New Jersey Herald, Feb 23, 2018
Special hunt gets 47 deer on Lake Michigan island once eyed as sportsman’s preserve, MLink, Nov 21, 2017
Natural Lands staff track impact deer have on ecosystem, The Ithacan, Nov 9, 2017
Are Native Tree Seedlings Facilitated by an Invasive Shrub Where White-Tailed Deer Are Abundant?, BioOne, Oct 1, 2017
Going Green: Deer in Urban Areas, Spectrum News, July 31, 2017
Assessing Forest Health in Central New Jersey: Impacts of Deer and Invasive Plant Species, 9th Annual Sustainable Raritan Conference, June 9, 2017
Plans for habitat and wildlife conservation need to consider the risk of Lyme disease, University of Glasgow, May 9, 2017
Effects of conservation management of landscapes and vertebrate communities on Lyme borreliosis risk in the United Kingdom, Transactions of the Royal Society, April 24, 2017
Wisconsin’s deer overpopulation harms soil, plant growth, Fox 6News, Feb 10, 2017
- Wisconsin Public Radio reports that biologists have known for a long time that an overabundance of deer negatively affects the number and diversity of plants in our forests. But a new study headed by Autumn Sabo, a PhD candidate at the university, suggests it’s also changing the soil beneath the forest floor. Sabo took samples from test plots that have been fenced off from deer for up to two decades and found less soil compaction as well as a thinner layer of depleted soil, which is called a leach zone.
- When the Killing’s Done, Island Wildlife Roars Back, Takeapart, March 21, 2016
New research shows that eradicating invasive species lets unique and imperiled wildlife recover. Jones, who teaches at Northern Illinois University, is the lead author on a study published Monday in Proceedings of the National Academy of Sciences that looks at the long-term effects of eradicating cats, rats, goats, pigs, and other invasive mammals from islands. On the 181 islands where biologists have conducted follow-up studies, Jones and her coauthors found that eradication turns out to be one of the most effective strategies “for protecting the world’s most threatened species.”
- Why ecologists support Ann Arbor’s deer cull, The Bridge, Jan 14, 2016
- I have discussed the urban deer issue with academic biologists at the University of Michigan, including ecologists, botanists, zoologists, restoration ecologists and landscape architects. We are all in support of city council’s decision to conduct a cull.
From ecological and conservation perspectives, an ideal deer herd will coexist with a full range of native species. By several measures, Ann Arbor’s herd size has surpassed this threshold. Botanists at the U-M have long noted declines in native plants that deer favor, through decades of observation, and by comparison with landscapes where deer are excluded or managed. In a 2015 study, an ecological team surveyed browsing impacts in Ann Arbor’s Bird Hills Nature Area. They found browsing damage in 80 percent of the tree saplings.
- TROPHIC CASCADE EFFECTS OF DEER OVERABUNDANCE ON CONNECTICUT’S NATIVE VEGETATION AND SMALL MAMMAL POPULATION, University of Connecticut Masters Thesis, 2014
The research conducted on this trophic cascade may afford new insight into habitat rest oration as well as wildlife and disease management. Hopefully, the findings of this research will aid in rectifying the disruption in the Northeast environment that has led to a disturbed cascade and an increase in blacklegged ticks infected with Borrelia burgdorferi.
- The Pennsylvania Department of Conservation and Natural Resources just produced a brochure, Healthy Forests – Healthy Deer, Finding the Right Balance, 2012
- Because of the importance of healthy forests to people and the whole forest ecosystem, DCNR has long advocated balancing deer populations using habitat quality as the primary measure. That is, the health of the forest understory and the forest’s capacity to renew itself.
- Deer Can Be Too Many, Too Few, or Just Enough Too Few, or Just Enough for Healthy Forest, US Forest Service, 2012
In some places, deer populations are now so high that they cause long-term negative ecological effects, eating out forest understories of wildflowers, shrubs, and tree seedlings. Such forests are pretty obvious—consisting only of tree trunks and a few deer-resistant shrub species. Often, the only understory plant species are native New York and hay-scented ferns and nonnative invasive plants such as barberry, burning bush, and garlic mustard. In areas with high deer densities and little deer forage, the forest may not regrow at all after disturbance, leaving “fern deserts.”
- Is HSUS Bad for the Environment? HumaneWatch.org, April 9, 2014
Animal rights groups ideologically opposed to hunting, such as the Humane Society of the United States, have proposed deer “birth control” as a “humane” means of dealing with deer overpopulation. Cambrone, however, points out the impracticality of HSUS’s preferred (and seemingly only) way of managing deer:
Some environmentalists, especially in urban areas, oppose hunting to cull the herds and argue instead for deer “birth control.” Yet contrary to persistent urban legend, there’s no handy oral deer contraceptive we can slip into a pile of acorns. Nor is there a permanent contraceptive that can be delivered with a single shot from a dart gun. Currently available immunocontraceptive agents have no effect on 10%-15% of the treated does. Even when they’re effective the first year, booster shots are needed in subsequent years.
Then, too, it’s difficult to inject enough does in a large, free-roaming population—and more difficult still to inject each one repeatedly, right on schedule. Even if we could, all those deer would still be present for years—still eating, still wandering out into traffic, and every day welcoming their fertile new friends arriving from nearby. The most optimistic cost estimates for each injection are around $500 per deer. Even surgical sterilization has been tried in a few locales. Although it costs over $1,000 per deer, it is 100% reliable and permanent.
- Effects of climate change, deer and invasive species on forests, Lee E. Frelich, Director, The University of
Minnesota Center for Forest Ecology, 2013
Global warming is about the effects of droughts, storms, fires, bugs, worms and deer on the forest.
- Changing Landscapes for White-Tailed Deer Management in the 21st Century: Parcelization of Land Ownership and Evolving Stakeholder Values in Michigan, Wildlife Society Bulletin, Sept 2011
To address this challenge, we 1) quantified how landscape characteristics in southwestern and south-central Michigan, USA affect the distribution and population characteristics of deer throughout agro-forested landscapes, 2) quantified factors affecting stakeholder acceptance capacity for deer, and 3) present a deer management framework based on desired levels of impacts in relation to existing conditions. Knowledge of deer ecology, landscape characteristics, and responses of stakeholders to deer are critical for managing the impacts of white-tailed deer.
- Legacy of top-down herbivore pressure ricochets back up multiple trophic levels in forest canopies over 30 years, Ecosphere, Jan 2011
Removal of top-down control on herbivores can result in a trophic cascade where herbivore pressure on plants results in changes in plant communities. These altered plant communities are hypothesized to exert bottom-up control on subsequent herbivory via changes in plant quality or productivity. But it remains untested whether top-down perturbation causes long term changes in plants that ricochet back up the new food chain that depends on them. In a large-scale, 30-yr controlled field experiment, we show that 10 yr of top-down control of an ungulate herbivore (white-tailed deer, Odocoileus virginianus) created contrasting forest tree communities exerting bottom-up effects that ricochet back up 3 trophic levels 20–30 yr later. Higher ungulate densities during stand initiation caused significant reductions in tree species diversity, canopy foliage density, canopy insect density, and bird density in young (ca. 30 yr old) forests. Because recruitment of trees from seedlings to the canopy occurs over a relatively brief period (ca. 10 yr), with membership in the canopy lasting an order of magnitude longer, our results show that even short-term perturbations in ungulate density may cause centuries-long disruptions to forest ecosystem structure and function. In documenting this five-step trophic ricochet, we unite key concepts of trophic theory with the extensive literature on effects of ungulate overabundance. As predators decline and ungulate herbivores increase worldwide, similar impacts may result that persist long after herbivore density becomes effectively managed.
- History of Deer Population in Indiana, 2010, Presentation by IU Biologists Clay & Shelton
Trophic cascades are often drastically disrupted by human interventions— for example,
when wolves and cougars are removed, allowing deer and beaver to become destructive— yet have only recently begun to be considered in the development of conservation and management strategies.
- Matthaei Botanical Gardens & Nichols Arboretum, 2009 Fiscal Year Annual Report, UM
We’re also fortunate that our lands encompass much of the natural heritage that once was southeastern Michigan—oak woodlands, floodplain woods, tamarack swamps, savannas or oak openings,
prairies, fens, and bogs. We have significant frontage on the Huron River as well as a major stretch of Fleming Creek, one of the healthiest streams in our area. While it may seem paradoxical, these sites must be carefully managed to preserve their “naturalness” for future generations, as their lands and waters battle constant threats from invasive species, over-population of deer, and changes in hydrology.
- F R I E N D S for friends of the University of Michigan’s Matthaei Botanical Gardens and Nichols Arboretum, Spring 2006
Come take a walk past a woodland gem, Kirk Woods, located next to the Demonstration Prairie at the northern portion of the Gardens. It is remnant oak-opening woodland. Oak-opening
ecosystems are few and far between in Southeast Michigan. With fire suppression and deer browse leading to a predominance of fire susceptible species like maple, this type of forest is fast becoming a thing of the past. Oak-opening ecosystems were once very common in SE Michigan and were perpetuated by the Native American cultural practice of burning their land. This custom helped to stimulate certain plants used for food and other purposes, aided in hunting, and provided open views of neighboring tribes and incoming settlers.
- Wildlife Damage Management Fact Sheet Series: White-tailed Deer, Cornell Cooperative Extension, Ithaca, N.Y, 2001.
Annual estimates of deer damage are reported to exceed $2 billion nationwide, including $1 billion in car damages, more than $100 million in agricultural crop damage, $750 million in damage to the timber industry, and more than $250 million in damage to metropolitan households (e.g., landscape plantings). These estimates are conservative, and it is often difficult to obtain reliable statistics for wildlife-related losses.
- Studying Deer Impacts at New York’s Binghamton University, AlCambrone.com (blog), Sept 25, 2014
- Deer impacts on Tompkins County and Ithaca environment invoke hunting programs, Ithaca.com, November 2013
- Cleveland Metroparks: Current Issues- Deer Management. ClevelandMetroParks.com
- How Deer and Beaver Affect You and Your Land and What You Can Do About It, Cornell University
- Forester Perceptions of Deer Depredation On the Forests of Michigan, Michigan Society of American Foresters, January 2008
The responses from foresters clearly indicate that, in their professional opinions, negative ecological impacts of deer depredation are common across wide portions of Michigan’s forests. While this survey assessed the perspective of foresters regarding deer depredation, the collective experience of foresters is extensive.
- MINIMIZING DEER DAMAGE TO FOREST VEGETATION THROUGH AGGRESSIVE DEER POPULATION MANAGEMENT, Raymond J. Winchcombe, Institute of Ecosystem Studies, Millbrook, NY, Digital Commons, Feb 2, 1991
The primary objective of the hunts was to remove sufficient numbers of adult female deer each year to stabilize herd growth and minimize browsing pressure.
The Future of Oak Forests: Ecology, Management, and Regeneration, Ohio State University Extension, Jan 2017
Rhode Island’s Large Deer Population More Immediate Threat to State’s Forests Than Climate Change, RI eco, Dec 1, 2016
Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure, PeerJ, Sept 2016
Of wolves, deer, maples and wildflowers, Great Lakes Echo, June 26, 2016
Impacts of deer on northeastern forests and strategies for control, Paul Curtis, Cornell University, June 2016
Deer-Forest Study, Penn State, Dept of Ecosystem Science and Management
Pattern and Drivers of White-Tailed Deer (Odocoileus virginianus) Herbivory on Tree Saplings across a Plateau Landscape, Jonathan P. Evans, et al., Forests, May 6, 2016
Interactions of Deer and Invasive Species: Metrics and Strategies for Suburban Deer Management, Bernd Blossey, Cornell University, March 22, 2016
The effects of varying deer density on natural regeneration in woodlands in lowland Britain, Forestry, 2009
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