Small mammal surveys on Grant-Kohrs Ranch National Historic Site

Pearson, Dean; Socie, Kathryn; Ruggiero, Leonard

The current report provides the results of a small mammal survey conducted on Grant-Kohrs Ranch National Historic Site (GKR) in the summers of 2002 and 2003. The primary objective was to survey the small mammals of GKR in an effort to achieve a 90% inventory of the small mammal communities there. Given the potentially high species richness and the potential rarity of some prospective community members, we conducted intensive sampling throughout GKR using a range of trapping techniques to ensure that the suite of traps provided the most effective means of sampling the entire small mammal community. Additionally, the use of snap traps and pitfalls provided voucher specimens for identification purposes. Since at least one fourth of the species potentially present are difficult to impossible to conclusively identify without using dental, skull, or baculum characteristics (e.g. nearly all the shrews, several voles, and some chipmunks and mice), examination of these characteristics were necessary to approach the 90% census goal and establish conclusive species identifications. A secondary objective of this study was to evaluate small mammal habitat use in the context of exotic plant invasions occurring within the park.