Winter Browse Availability and Use by White-Tailed Deer in Southeastern Indiana

Abstract

Browse availability and use by white-tailed deer (Odocoileus virginianus) in southeastern Indiana were studied during winter 1978-79. Significant positive regressions were found between browse use and availability for the entire study area (habitat ignored) and within mature forests and second-growth woods. These data support the hypothesis that deer forage nonselectively in winter. No relationship was found between use and availability in oldfields. Browse use was lower in oldfields than in mature forests and secondgrowth woods, but the availability of browse did not differ between habitats. J. WILDL. MANAGE. 49(1): 120-124 White-tailed deer have evolved numerous physiological and behavioral adaptations for survival during the thermal and nutritional stresses of winter. Conservation of energy is achieved through lower metabolic rates, reduced activity, restricted home-range size, increased shelter-seeking behavior, and greater insulating properties of winter pelage (Mautz 1978, Moen 1978). In addition, insulation and energy are provided by fat reserves deposited during summer and autumn when food resource availability and quality are favorable (Short 1975, Mautz 1978). Winter forage is frequently poorly digested (Robbins and Moen 1975, Short 1975, Mautz et al. 1976), but is necessary to slow the catabolism of finite fat deposits (Mautz 1978). Nudds (1980) suggested that northern deer should adopt a generalist foraging strategy during winter in response to low food availability and quality. With such a strategy, relative use of food types is approximately equal to relative availability. He argued that energy acquisition should become the critical factor for survival and optimization of the diet for other nutrients should be relaxed. Data from Wetzel et al. (1975) were reanalyzed by Nudds (1980) and supported the hypothesis of diet generalization in winter. We examined the availability and use of woody browse by white-tailed deer in southeastern Indiana during winter (Dec-Mar). We tested the hypothesis that browse use is positively related to availability. We thank T. D. Nudds and L. D. Vangilder for reviewing earlier drafts of this manuscript. STUDY AREA The 2.5-km2 study area encompassed the Brookville Ecology Research Center and adjacent agricultural and state park lands south of Liberty, Union County, Indiana. A diversity of habitats was present, including upland and bottomland mature forest, second-growth woods, oldfields, and cropland. Topography varied with steep slopes rising from river bottoms to level upland. Dominant features of the landscape included the man-made impoundments of Brookville and Whitewater lakes. Population density of white-tailed deer in the study area was estimated at ~14 individuals/km2 (LaGory 1979). Mature forest occupied 50% of the study area and consisted of mixed deciduous hardwoods. Major canopy species in upland sites were oak (Quercus), white ash (Fraxinus americana), sugar maple (Acer saccharum), and American be ch (Fagus grandifolia). American sycamore (Platanus occidentalis), boxelder maple (A. negundo), and eastern cottonwood (Populus deltoides) were common canopy species in bottomland forests. Abandoned agricultural cropland and pasture existed as oldfields (26% of the study area) and second-growth woods (7%). Herbaceous plants included goldenrod (Solidago), aster (Aster), milkweed (Asclepias), wild carrot (Daucus carota), ragweed (Ambrosia), and several native and domesticated grasses. Shrubs and young trees common to oldfields and second-growth woods included osage-orange (Maclura pomifera), common honeylocust (Gleditsia triacanthos), wild cherry (Prunus), dogwood (Cornus), elm (Ulmus), white