ALBERT

Description: Abstract Many of the processes that govern the viability of animal populations vary spatially, yet population viability analyses (PVAs) that account explicitly for spatial variation are rare. We develop a PVA model that incorporates autocorrelation into the analysis of local demographic information to produce spatially explicit estimates of demography and viability at relatively fine spatial scales across a large spatial extent. We use a hierarchical, spatial, autoregressive model for capture–recapture data from multiple locations to obtain spatially explicit estimates of adult survival (ϕad), juvenile survival (ϕjuv), and juvenile‐to‐adult transition rates (ψ), and a spatial autoregressive model for recruitment data from multiple locations to obtain spatially explicit estimates of recruitment (R). We combine local estimates of demographic rates in stage‐structured population models to estimate the rate of population change (λ), then use estimates of λ (and its uncertainty) to forecast changes in local abundance and produce spatially explicit estimates of viability (probability of extirpation, Pex). We apply the model to demographic data for the Sonoran desert tortoise (Gopherus morafkai) collected across its geographic range in Arizona. There was modest spatial variation in λ^ (0.94–1.03), which reflected spatial variation in ϕ^ad (0.85–0.95), ϕ^juv (0.70–0.89), and ψ^ (0.07–0.13). Recruitment data were too sparse for spatially explicit estimates; therefore, we used a range‐wide estimate (R^ = 0.32 1‐yr‐old females per female per year). Spatial patterns in demographic rates were complex, but ϕ^ad, ϕ^juv, and λ^ tended to be lower and ψ^ higher in the northwestern portion of the range. Spatial patterns in Pex varied with local abundance. For local abundances 〉500, Pex was near zero (〈0.05) across most of the range after 100 yr; as abundances decreased, however, Pex approached one in the northwestern portion of the range and remained low elsewhere. When local abundances were 〈50, western and southern populations were vulnerable (Pex 〉 0.25). This approach to PVA offers the potential to reveal spatial patterns in demography and viability that can inform conservation and management at multiple spatial scales, provide insight into scale‐related investigations in population ecology, and improve basic ecological knowledge of landscape‐level phenomena.

Description: A capture cross section value is often assigned to Si–SiO 2 interface defects. Using a kinetic variation of the charge pumping technique and transition state theory, we show that the value of capture cross section is extremely sensitive to the measurement approach and does not provide any meaningful insight into the physics involved. We argue that capture cross section is neither a physical property of interface defects nor is there any need to assign capture cross section values.

Description: The Bulletin of the Ecological Society of America, Volume 100, Issue 1, January 2019.