Long-term population sampling for the Preble’s meadow jumping mouse (PMJM) has allowed Rob Schorr to estimate population change (λ) for the population along Monument Creek at the U.S. Air Force Academy (Academy). Using mark-recapture techniques and a novel population model that allows estimation of survival and recruitment, Schorr estimated changes in PMJM λ from 2000-2006. Although λ varied annually, the 7-year mean showed a declining population, and λ was less impacted by changes in PMJM survival than by changes in PMJM recruitment.
|A Preble’s meadow jumping mouse (Zapus hudsonius preblei) keeps a sharp eye on the photographer.
Recruitment can be influenced by immigration or reproduction. Given the loss of habitat along eastern tributaries of Monument Creek, there are limited opportunities for increasing immigration from these tributaries and this may be a driving force during this time. However, Schorr warns that this may be a temporary decline that will be compensated by increased reproduction or immigration from western tributaries that are on the Academy.
|PMJM habitat along Monument Creek.
This study will be published in the October 2012 Journal of Mammalogy.
|Rob Schorr and friend. Photo by James Dwyer.