Category Archives: ecosystem

It’s rare plants versus deer in the College Woods

It’s rare plants versus deer in the College Woods
William & Mary News, Jan 15, 2015

What was once lush is now sparse. “This isn’t good for the forest, but it isn’t good for the deer either,” said Dalgleish. The problem is not simply that the deer are eating too many plants, but that the plants are growing back smaller and smaller each year. The deer are eating the plants so quickly that they are unable to store enough regenerative material to grow back to their original height the next year.

Long-Term Regional Shifts in Plant Community Composition Are Largely Explained by Local Deer Impact Experiments

Long-Term Regional Shifts in Plant Community Composition Are Largely Explained by Local Deer Impact Experiments
PlosOne, Dec 31, 2014

The fact that herbivores and predators exert top-down effects to alter community composition and dynamics at lower trophic levels is no longer controversial, yet we still lack evidence of the full nature, extent, and longer-term effects of these impacts. Here, we use results from a set of replicated experiments on the local impacts of white-tailed deer to evaluate the extent to which such impacts could account for half-century shifts in forest plant communities across the upper Midwest, USA. We measured species’ responses to deer at four sites using 10–20 year-old deer exclosures. Among common species, eight were more abundant outside the exclosures, seven were commoner inside, and 16 had similar abundances in- and outside. Deer herbivory greatly increased the abundance of ferns and graminoids and doubled the abundance of exotic plants. In contrast, deer greatly reduced tree regeneration, shrub cover (100–200 fold in two species), plant height, plant reproduction, and the abundance of forbs. None of 36 focal species increased in reproduction or grew taller in the presence of deer, contrary to expectations. We compared these results to data on 50-year regional shifts in species abundances across 62 sites. The effects of herbivory by white-tailed deer accurately account for many of the long-term regional shifts observed in species’ abundances (R2 = 0.41). These results support the conjecture that deer impacts have driven many of the regional shifts in forest understory cover and composition observed in recent decades.

Hunting gives deer-damaged forests in state parks a shot at recovery

Hunting gives deer-damaged forests in state parks a shot at recovery
Phys.org, July 9, 2014

A research team led by Michael Jenkins, associate professor of forest ecology, found that a 17-year-long Indiana Department of Natural Resources policy of organizing hunts in state parks has successfully spurred the regrowth of native tree seedlings, herbs and wildflowers rendered scarce by browsing deer.

“We can’t put nature in a glass dome and think it’s going to regulate itself,” he said. “Because our actions have made the natural world the way it is, we have an obligation to practice stewardship to maintain ecological balance.”

Indiana state parks historically did not allow hunting. But by the 1990s, white-tailed deer populations in parks had swelled to such size that many species of native wildflowers such as trillium and lilies largely disappeared, replaced by wild ginger and exotic species such as garlic mustard and Japanese stiltgrass, plants not favored by deer. Oak and ash tree seedlings gave way to highly deer-resistant or unpalatable trees such as pawpaw.

Ann Arbor Government, Urban & Community Forest Management Plan

Ann Arbor Government, Urban & Community Forest Management Plan, adopted June 2, 2014

VISION: Ann Arbor’s urban and community forest is a prominent feature of the city valued by its citizens for the positive contributions it makes to the quality of life and character of the community. The urban and community forest is a vital part of the city’s green infrastructure system and is managed sustainably through sound practices, policies and community stewardship to provide environmental,
social and economic benefits today and into the future.

other information

Excessive deer populations hurt native plant biodiversity

Excessive deer populations hurt native plant biodiversity
PhysOrg, March 11, 2014

To study the effect of rampant deer on trillium and garlic mustard populations, Kalisz and colleagues established multiple 196-square-meter plots in the forest. Half were fenced to exclude deer. Years of observation and hours of statistical analysis later, Kalisz and her colleagues have found that in plots where deer were excluded, the trillium population is increasing and the garlic mustard population is trending toward zero.

Identification and Management of Multiple Threats to Rare and Endangered Plant Species

Identification and Management of Multiple Threats to Rare and Endangered Plant Species
RC-1542, SERDP and ESTCP
Dr. Bernd Blossey, Cornell University
Sept 2013

Density and species composition of monitored stressor organisms (earthworms, slugs, and B. pellucidus) varied across field sites and years. Unexpectedly, it was found that earthworm density and biomass decreased in the fenced plots, indicating a possible, but unforeseen, interaction between earthworms and deer. In just five years, it was found that all three target non-native plants had significantly lower abundance (frequency, cover, and/or density) in fenced plots, in response to deer exclusion. This is particularly true for the short-lived M. vimineum and A. petiolata, which are annual and biennial, respectively. Simultaneously, native vegetation responded positively to deer exclusion. Results indicate that it may be possible to reduce abundance of non-native plants simply by substantially reducing deer density.

Report – 2011/2012 Deer Management Plan Implementation

Report – 2011/2012 Deer Management Plan Implementation, Report to Board of Commissioners
HURON-CLINTON METROPOLITAN AUTHORITY, Meeting of September 13, 2012

It is the consensus of natural area managers that controlling excessive deer populations is critical to the long term health and viability of the native ecosystems that these animals are a component of. The management efforts the Metroparks established has had a direct impact on insuring that the parks’ high quality natural areas remain intact for future generations to enjoy.