The Impact of White‐Tailed Deer on Agricultural Landscapes in 3 National Historical Parks in Maryland

Abstract

The legislative authorization of some United States national historical parks (NHP) includes maintaining an agricultural landscape as a management objective. This management objective can prove difficult to accomplish in some NHP given increasing white‐tailed deer (Odocoileus virginianus) densities. Our goal was to quantify the impact of white‐tailed deer foraging on agricultural landscapes in forested NHPs in Maryland, USA. We monitored 12 and 13 corn (Zea mays) fields at 3 NHP during the 2003 and 2004, respectively. Each field had ***3 5 × 5‐m fenced and unfenced plots along the edge and a similar set within the interior of the field. Within each plot we examined the number of stalks with corn, corn ear quality, and field weight prior to harvest. Fenced plots had higher weights of corn, more stalks with corn ears, and higher quality corn than unfenced plots. Estimates of silage yield based on crop weights indicate deer reduced silage yield in individual fields by 5‐43% during the study period. Crop loss differed between years and fields, with plots in the Chesapeake and Ohio Canal NHP sustaining the highest crop weight loss (28%). Eventual crop loss was correlated with proportion of corn plants browsed within 2 weeks of emergence. Some variability in loss between fields was due to landscape metrics, as fields surrounded by more forest experienced the highest loss. Our results indicate the NHP agriculture fields we studied receive significant deer damage to corn crops and may not be able to maintain mandated management without regulating deer numbers.

Ecology and management of white‐tailed deer in a changing world

“…In human‐modified forests, deer can increase their access to forage by moving between forested and human landscapes 32–34 . Agricultural crop damage is highest along the forest boundary, and these crops enhance the productivity of the landscape 35,36 . Forestry practices create large patches of early successional trees that are readily fed upon by deer 37,38 .…”

“…It is difficult to generalize the current densities of deer in eastern United States and their impact on forest resources. Unhunted population in moderate or highly productive landscapes are found in densities of 30–50 deer/km 2 , with isolated examples of >100 deer/km 2 24,26,27,32,35,62 . Hunted populations generally are in a range of 15–30 deer/km 2 , and preferred browse species have been demonstrated to be impacted at 3–10 deer km 2 21,24,26,32,40 .…”

“…[32][33][34] Agricultural crop damage is highest along the forest boundary, and these crops enhance the productivity of the landscape. 35,36 Forestry practices create large patches of early successional trees that are readily fed upon by deer. 37,38 Mature forest productivity alone likely would not support high deer densities, but sea-sonal access to human-added productivity results in seasonal bouts of heavy browsing pressure on natural systems.…”

“…Unhunted population in moderate or highly productive landscapes are found in densities of 30-50 deer/km 2 , with isolated examples of >100 deer/km 2 . 24,26,27,32,35,62 Hunted populations generally are in a range of 15-30 deer/km 2 , and preferred browse species have been demonstrated to be impacted at 3-10 deer km 2 . 21,24,26,32,40 Without affecting functional foraging responses, it will be difficult to maintain preferred browse species through use of hunters unless deer densities are reduced to numbers significantly below biological carrying capacity.…”

Labor costs and crop protection from wildlife predation: the case of elephants in Gabon

“…Conflicts of interest between farmers and wildlife are ubiquitous. Substantial agricultural losses have been documented in situations around the globe ranging from livestock predation by carnivores (Baker et al, 2008) to crop predation by rodents (Elmouttie and Wilson, 2005; Mwanjabe et al, 2002), primates (Engeman et al, 2010; Hill, 2000), and large mammals (Naughton‐Treves, 1998; Stewart et al, 2007). While increasing agricultural productivity is considered one of the most effective means of reducing extreme poverty (World Bank, 2007), crop raiding by wildlife can greatly diminish returns on agriculture.…”