Type: report

Article abstract: This document presents a monitoring protocol for the Stephens’ kangaroo rat (Dipodomys stephensi, SKR) on Marine Corps Base Camp Pendleton (MCBCP). A two-day scientific workshop was held in 2004 for the purpose of designing this program. The workshop attendees included a four member Scientific Peer Review Panel with expertise in spatial and statistical monitoring design and SKR biology, and additional biologists from several federal, state, and local wildlife agencies. The panel and other members reviewed and discussed SKR life history, conceptual models, monitoring schemes, and detection methods before reaching consensus on the basics of a monitoring program. Protocol specifics were determined by consultation among the USGS, the scientific panel, and MCBCP after the workshop. There is a large body of evidence to show that SKR populations are both spatially and temporally dynamic. SKR abundance and capture probabilities are highly variable making detection of demographic trends problematic and time intensive. Suitable habitat for SKR may also vary through time and space in relation to disturbance and vegetation succession. This is particularly true on MCBCP, where there is a relatively high level of disturbance from frequent fires and military training activities. In consideration of these and other factors, we designed a relatively simple, multi-tiered, habitat-based, adaptive monitoring program for SKR. This monitoring program will track yearly trends in the total area occupied by SKR on base over a large number of fixed sample plots. It includes measurement of habitat and environmental variables that are hypothesized to affect the probability of occupancy, rate of colonization, and/or rate of extinction over time. Predictors that are found to be significant will be used for habitat-based recommendations for management. It is unknown whether trends in SKR distribution are directly related to trends in SKR abundance; therefore, the program includes a density index. We considered active burrow counts for use as an index, as they have been shown to correlate and trend with SKR density estimates from live- 1 trapping. However, previous monitoring efforts on MCBCP have shown that even in optimum habitat, SKR frequently co-exist with the sympatric Dulzura kangaroo rat (Dipodomys simulans, DKR), and that the proportion of SKR/DKR is both spatially and temporally variable. As a result, we cannot expect a consistent relationship between kangaroo rat burrow co