Use of playback alarm calls to detect and quantify habitat use by Richardson's ground squirrels.

摘要

As part of a larger study on prairie ecosystems, we evaluated the use of playback alarm calls as a monitoring protocol to obtain more representative measures of the detection rate and abundance of Richardson's ground squirrels (Spermophilus richardsonii). The study was conducted in the natural grassland region of southern Alberta, Canada. Using these data we quantified habitat preferences of Richardson's ground squirrels by comparing availability and use of native pastures and cultivated lands. Lastly, we determined whether grass height influenced Richardson's ground squirrel habitat use. Results from surveys indicated that the playback of alarm calls increased levels of detection of Richardson's ground squirrels in 2003 (t24=-6.82, P<0.001) and 2004 (t32=-5.91, P<0.001) and estimates of abundance in 2003 (t24=-4.35, P<0.001) and 2004 (t32=-6.82, P<0.001). Our habitat comparisons showed that Richardson's ground squirrels preferred native pasture and selected against cultivated lands when compared to habitat type availability (X21=45.22, P<0.001). Ground squirrels selected native pasture with grass heights between 0-30 cm and selected against areas with tall grass (>30 cm; X21=7.69, P=0.0056). Our results suggest that playback alarm calls may constitute an important monitoring protocol to determine Richardson's ground squirrel abundance and habitat use..