Evaluating the recovery of vegetation communities in Indiana state parks after more than a decade of deer population reduction

Lindsay Hughes Jenkins, Purdue University

Abstract

White-tailed deer were extirpated from Indiana in the late 1800s, but populations across the state rebounded in the late 20th century following successful reintroduction in the 1930s and 1940s. Populations in state parks grew large and were not reduced by hunting as occurred on other properties throughout Indiana beginning in the 1950s. Excessive deer browse was severely affecting herbaceous plant cover and woody stem density by the early 1990s. Controlled hunts were initiated in the state parks in the 1990s to reduce the impact that deer were having on vegetation communities. In 1996/1997 a study was conducted to quantify the impact of deer browsing on the plant communities of state parks. I resampled these plots in 2010 to determine the degree of recovery since 1996/1997. Fifteen state parks and five reference areas that have always been hunted were sampled in this study. Percent cover and species composition were measured in the herbaceous layer (<50 cm>tall) and woody stem density and composition were measured for three height classes of woody vegetation (<50 >cm, 50-200 cm, and >200 cm). Herbaceous percent cover, S, and H’ significantly increased over time in the state parks and exceeded the changes observed in the reference areas. NMS ordinations revealed that state park herbaceous layer composition was generally becoming increasingly similar to reference areas and that current composition was related to either long-term or short-term deer reductions. There was a significant increase in the woody stem densities of the 50-200 cm height class in state parks and reference areas, but the increase in state parks was much greater. Woody vegetation S, E, and H’ increased significantly in state parks, but not the reference areas. Also, the densities of more palatable species significantly increased in state parks in the lower height classes. Increases in state park herbaceous percent cover, woody stem density in the 50-200 cm height class, and S, E, and H’ in both relative to reference areas suggest that deer reductions are responsible for these changes and should therefore be continued in order to maintain these conditions.

Degree

M.S.

Advisors

Jenkins, Purdue University.

Subject Area

Wildlife Management|Ecology

COinS