Individual and interactive effects of white-tailed deer and woody invasive plants on native tree seedlings in an early successional forest

Regeneration failure is a pressing issue endangering the health of many forests in North America. Invasive plants and Odocoileus virginianus (white-tailed deer) contribute to regeneration failure by impacting tree seedling survival and growth. This study investigated the individual and interactive effects of deer and woody invasive plants on seedlings in an early successional forest. In a stand of Juniperus virginiana near Oxford, OH, we initiated a factorial experiment with each combination of deer access/exclosure and invasive woody plants removed/not removed. Deer were excluded with 2.13 m tall fences using four trees as corner posts. We planted native tree seedlings and monitored natural regeneration (tree seedlings 0.3–2 m) in each plot. Survival was low for planted seedlings and growth differed across species but, in general, change in height was significantly impacted by deer and the interaction: excluding deer resulted in less height loss and this effect was greater where invasives were present. Change in height of natural regeneration (mostly Fraxinus americana ) was significantly affected by deer; seedlings grew taller in deer exclosures. The total number of seedlings recruiting per plot did not differ among treatments. However, the number of recruits excluding F. americana seedlings showed a marginally significant interaction: number of recruits was greatest where deer and invasives were removed. Overall, deer had a greater impact than invasives on natural regeneration and planted seedlings. These small exclosures required minimal cost, installation time, and maintenance. These findings lead us to recommend this method to land managers.