Long-Term Effects of White-Tailed Deer Exclusion on the Invasion of Exotic Plants: A Case Study in a Mid-Atlantic Temperate Forest

PLoS One. 2016 Mar 28;11(3):e0151825. doi: 10.1371/journal.pone.0151825. eCollection 2016.

Abstract

Exotic plant invasions and chronic high levels of herbivory are two of the major biotic stressors impacting temperate forest ecosystems in eastern North America, and the two problems are often linked. We used a 4-ha deer exclosure maintained since 1991 to examine the influence of a generalist herbivore, white-tailed deer (Odocoileus virginianus), on the abundance of four exotic invasive (Rosa multiflora, Berberis thunbergii, Rubus phoenicolasius and Microstegium vimineum) and one native (Cynoglossum virginianum) plant species, within a 25.6-ha mature temperate forest dynamics plot in Virginia, USA. We identified significant predictors of the abundance of each focal species using generalized linear models incorporating 10 environmental and landscape variables. After controlling for those predictors, we applied our models to a 4-ha deer exclusion site and a 4-ha reference site, both embedded within the larger plot, to test the role of deer on the abundance of the focal species. Slope, edge effects and soil pH were the most frequent predictors of the abundance of the focal species on the larger plot. The abundance of C. virginianum, known to be deer-dispersed, was significantly lower in the exclosure. Similar patterns were detected for B. thunbergii, R. phoenicolasius and M. vimineum, whereas R. multiflora was more abundant within the exclosure. Our results indicate that chronic high deer density facilitates increased abundances of several exotic invasive plant species, with the notable exception of R. multiflora. We infer that the invasion of many exotic plant species that are browse-tolerant to white-tailed deer could be limited by reducing deer populations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Berberis / physiology
  • Biodiversity
  • Boraginaceae / physiology
  • Deer / physiology*
  • Ecosystem
  • Feeding Behavior / physiology*
  • Forests*
  • Geography
  • Hydrogen-Ion Concentration
  • Introduced Species*
  • Linear Models
  • Poaceae / physiology
  • Population Density
  • Population Dynamics
  • Rosa / physiology
  • Rubus / physiology
  • Soil / chemistry
  • Species Specificity
  • Time Factors
  • Virginia

Substances

  • Soil

Grants and funding

The Smithsonian Global Earth Observatory initiative (http://www.forestgeo.si.edu/), the Smithsonian Institution (http://www.si.edu/), and the HSBC Climate Partnership (http://www.theclimategroup.org/programs/hsbc-climate-partnership/) provided the funding for establishing the SCBI Large Forest Dynamics Plot. The Friends of the National Zoo (https://nationalzoo.si.edu/JoinFONZ/Join/) and Earthwatch Foundation (http://earthwatch.org/) supported the original exclosure fence installation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.