See the Paper: Effects of White-Tailed Deer (Odocoileus virginianus) on Diversity, Distribution, and Height of Tree Species in a Reforestation Field in Northfield, Minnesota

Background

After facing a steep population decline due to hunting and habitat loss during European colonization, white-tailed deer populations have since recovered and are now abundant across North America. Their range includes Minnesota, where they typically feed on twigs of woody plants and trees, especially in the winter. 

In the late 1800s, much of Southeastern Minnesota’s deciduous ‘Big Woods’ forests were cleared to make room for agriculture. However, Big Woods forests are essential to the health of Minnesota’s landscape and are the focus of many restoration efforts. White-tailed deer are heavily influential in the recovery of these forests, often decreasing the growth rate of tree seedlings and saplings, and preventing regeneration by browsing (eating twigs and leaves off of trees). Because of the abundance of white-tailed deer, ecologists and managers (including in the Natural Lands!) are interested in understanding the impacts of deer on reforested areas. One example of this research is from a St. Olaf student in 2009.

The Study

Rebecca Rand (Class of 2010, B.A. Environmental Studies) used two 10m x 10m exclosures (fences to keep deer out) to put on a four-year-old reforested plot in the Natural Lands, and marked two additional sites in the plot to serve as controls (areas where the deer can browse freely). 

At each of these sites species type and stem height were recorded for the woody plants within the area.  

The Findings

Rand commented that the findings of the study were hard to interpret due to the constraints of the timeframe and resources available, but noted that in many similar exclosure studies, the presence and abundance of deer seem to reduce the height and species density of woody plants. While Rand’s study did not find a significant difference between the height or density of woody plants when comparing exclosure sites with the controls, it did provide a basic understanding and data for future research at St. Olaf. 

Relevance

White-tailed deer populations continue to affect the landscape today, including in the Natural Lands. Big Woods forest restoration is a priority in the Natural Lands, and consideration of all influential factors is actively taking place. Learn more about Natural Lands habitat management here.

Citation

Rand, R. 2009. Effects of White-Tailed Deer (Odocoileus virginianus) on Diversity, Distribution, and Height of Tree Species in a Reforestation Field in Northfield, Minnesota. St. Olaf College Local Ecology Papers. https://elevator.stolaf.edu/naturallands/asset/viewAsset/581ceb90e758ae4d3368b787