Climatic drivers of pinyon mouse Peromyscus truei population dynamics in a resource‐restricted environment

Abstract

AbstractHighly variable patterns in temperature and rainfall events can have pronounced consequences for small mammals in resource‐restricted environments. Climatic factors can therefore play a crucial role in determining the fates of small mammal populations. We applied Pradel's temporal symmetry model to a 21‐year capture–recapture dataset to study population dynamics of the pinyon mouse (Peromyscus truei) in a semi‐arid mixed oak woodland in California, USA. We examined time‐, season‐ and sex‐specific variation in realized population growth rate (λ) and its constituent vital rates, apparent survival and recruitment. We also tested the influence of climatic factors on these rates. Overall monthly apparent survival was 0.81 ± 0.004 (estimate ± SE). Survival was generally higher during wetter months (October–May) but varied over time. Monthly recruitment rate was 0.18 ± 0.01, ranging from 0.07 ± 0.01 to 0.63 ± 0.07. Although population growth rate (λ) was highly variable, overall monthly growth rate was close to 1.0, indicating a stable population during the study period (λ ± SE = 0.99 ± 0.01). Average temperature and its variability negatively affected survival, whereas rainfall positively influenced survival and recruitment rates, and thus the population growth rate. Our results suggest that seasonal rainfall and variation in temperature at the local scale, rather than regional climatic patterns, more strongly affected vital rates in this population. Discerning such linkages between species' population dynamics and environmental variability are critical for understanding local and regional impacts of global climate change, and for gauging viability and resilience of populations in resource‐restricted environments.