Carrying Capacity of Age-Specific Habitat Zones within Black-Tailed Prairie Dog Colonies: A Baseline Preceding Black-Footed Ferret Reintroduction

Abstract

Plant-animal interactions vary strongly between habitat zones characterized by the duration of colonization (age-specific) within a black-tailed prairie dog (Cynomys ludovicianus) town (Cincotta et al. 1984). These interactions largely determine vegetation composition, diet composition and quality, and population demographics of habitat zones. The ecology of the black-tailed prairie dog in Badlands National Park (BNP) has been described by Cincotta et al. (1984) and Sharps and Uresk (1990). Yet, there is still uncertainty about the plant-animal relationships which underpin prairie dog carrying capacity in different habitat zones. Understanding the variability in the ecology of black-tailed prairie dogs between habitat zones of mature towns is fundamental to successful reintroduction of the black-footed ferret (Mustela nigripes) into southwestern South Dakota. The predator-prey relationship between black-tailed prairie dogs and black-footed ferrets is dependent in large part upon density of prey. Additionally, an understanding of black-tailed prairie dog population and foraging ecology will be a required contribution by BNP to the development of a multiple large and small herbivore carrying capacity management model. For the purposes of this proposal, carrying capacity is defined as an estimate of densities of prairie dogs supportable at different levels of forage availability and quality (Hobbs and Swift 1985). Of the habitat zones in an aging prairie dog town, the old-town centers (OTC) and young-town edge (YTE) zones offer the most widely differing habitat characterizations (Cincotta et al. 1984), and should provide the most interesting test of the effect of habitat quality on prairie dog carrying capacity. The objectives of this research are 1) To estimate the carrying capacity of black-tailed prairie dogs in different habitat zones of an aging town, and 2) To understand how vegetation characteristics and prairie dog feeding habits influence the number of black­tailed prairie dogs which can be supported in different habitat zones.