Abstract Detail

Interactions of White-Tailed Deer and Invasive Plants in Forests of Eastern North America

Blossey, Bernd [1], Dávalos, Andrea [2], Nuzzo, Victoria [3].

An indicator approach to capture impacts of white-tailed deer and other ungulates on native plant species presence, performance and demography.

Management of white-tailed deer and other abundant ungulates is contested ground. Foresters, ecologists, conservationists, animal rights groups, suburban communities, hunters and local, state and federal land management agencies argue endlessly about the appropriate abundance of these charismatic ecosystem engineers. These arguments, unfortunately, often lack the evidentiary basis documenting the extent of impacts on individual plants, animals, ecosystems and foodwebs. Typical vegetation impact assessments include woody browse surveys and deer exclosures. While both have value, they also have major shortcomings: fenced plots exclude deer (and a number of other animals) entirely, the size of exclosures and time since fencing matter; and other fencing effects materialize. The woody browse index ignores herbaceous plants, and indicator species preferentially browsed in one area may remain untouched elsewhere. These differences can be a function of deer density as well as localized deer feeding preferences or differences in plant community composition or even differences in palatability or defense chemistry among plant genotypes. Furthermore, in heavily impacted areas the flora may be so depauperate that few remnant individuals remain for assessments. In addition deer interact with other stressors including earthworms or non-native plants. We propose a Sentinel Approach to assess deer browse impact on plants based on performance (survival, growth, reproductive effort) of individually marked specimens. These individuals can be remnant specimens in areas under assessment, or they can be planted. The selection of appropriate species is made locally based on community composition and ease of implementation. We have tested this approach in New York using a combination of planted specimens (3 month old oak seedling, Quercus rubra) and marked individuals of native perennials (Trillium, Maianthemum, Eurybia, Polygonatum) that are either protected from or exposed to deer herbivory. The strength of this approach is that typical problems associated with multiple stressor impacts can be avoided, areas devoid of vegetation but under heavy deer browse pressure can still be assessed, the methods are simple lending themselves to implementation by non-specialists, and this data collection can allow development of sophisticated demographic models and ecological forecasting. Implementation of regular or continued assessments can guide ungulate management based on meaningful evidence. We recommend assessing deer impacts on plants using marked individuals and their performance and hope that similar protocols can be developed to assess impacts on other biota.

1 - Cornell University, Natural Resources, Fernow Hall, Ithaca, NY, 14853, USA
2 - Cornell University, Natural Resources, Fernow Hall, Ithaca, NY, 14853, United States
3 - Natural Area Consultants, 1 West Hill School Road, Richford, New York, 13835, United States

Keywords:
Deet
indicator
sentinel
browse index.

Presentation Type: Colloquium Presentations
Session: C1, Interactions of white-tailed deer and invasive plants in forests of eastern North America
Location: Chatham Ballroom - C/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 1:45 PM
Number: C1001
Abstract ID:376
Candidate for Awards:None