PRIORITIZING HABITAT FOR SURVEYS OF AN UNCOMMON MAMMAL: A MODELING APPROACH APPLIED TO PYGMY RABBITS

Abstract

Determining occurrence and distribution is an essential 1st step in conservation planning for rare species. Spatial habitat models can be used to increase efficiency of field surveys and to improve understanding about factors influencing animal distributions. We used a modeling approach to identify and prioritize potential habitat for survey efforts for an uncommon mammal, the pygmy rabbit (Brachylagus idahoensis), for which detailed habitat data are limited. A base map of potential habitat in Idaho was defined using vegetation type and soil depth data. Documented locations (n = 164) were used to evaluate additional habitat variables to prioritize the potential habitat for surveys. We conducted field surveys to evaluate the predicted habitat attributes and document presence or absence of the species. Newly confirmed occurrences (n = 112) and absences (n = 139) were used to assess accuracy in predicting habitat priority ratings. Overall model accuracy was 65%. Eighty-four percent of the new occurrences were located in the 2 highest priority ranks, and <0.4% were located in the 2 lowest priority ranks. We offer several examples of how survey results can be used to improve the habitat model and increase efficiency of future survey efforts.