COMPARISON OF TECHNIQUES FOR DETERMINING THE NUTRITIONAL CARRYING-CAPACITY FOR WHITE-TAILED DEER

Estimates of carrying capacity for herbivores are useful for determini ng the relative value of different ranges. We compared 6 estimates of nutritional carrying capacity for white-tailed deer (Odocoileus virgin ianus L.): digestible energy consumed by tame deer, and 5 methods usin g forage supplies of dry matter, digestible energy, digestible nitroge n, dry matterdigestible energy, and dry matter*digestible nitrogen in two 1-ha enclosures of different shrub plant communities in southern Texas. For the north enclosure, carrying capacity estimates (90% CI) w ere 3.65 (CI = 3.61-3.69), 4.5 (CI = 3.7-5.3), 9.4 (CI = 7.3-11.5), 15 .2 (CI = 11.6-18.8), 3.5 (CI = 2.7-4.3), and 3.5 (CI = 2.7-4.3) deer h a(-1) 58 days(-1) for the digestible energy tame deer, dry matter, dig estible energy, digestible nitrogen, dry matterdigestible energy, and dry matterdigestible nitrogen techniques, respectively. Correspondin g estimates for the south enclosure were 2.6 (CI = 2.5-2.7), 3.5 (Ct = 3.2-3.9), 6.8 (Ct = 6.0-7.6), 10.1 (CI = 8.8-11.3), 2.1 (CI = 1.8-2.6 ), and 2.8 (CI = 2.4-3.1). Some methods for estimating carrying capaci ty provided different absolute estimates, but all produced similar rel ative estimates between enclosures. Similar relative results between e nclosures suggests any of the methods can be used to determine the rel ative nutritional quality of plant communities. However, the dry matte r-based technique was less expensive than the other techniques; theref ore, there is no need to use more costly techniques for determining th e relative stocking rates for white-tailed deer, unless forage quality differs greatly among plant communities.