Estimates of species' vital rates and an understanding of the factors affecting those parameters over time and space can provide crucial information for management and conservation. We used mark-recapture, reproductive output, and territory occupancy data collected during 1985-2013 to evaluate population processes of Northern Spotted Owls (Strix occidentalis caurina) in 11 study areas in Washington, Oregon, and northern California, USA. We estimated apparent survival, fecundity, recruitment, rate of population change, and local extinction and colonization rates, and investigated relationships between these parameters and the amount of suitable habitat, local and regional variation in meteorological conditions, and competition with Barred Owls (Strix varia). Data were analyzed for each area separately and in a meta-analysis of all areas combined, following a strict protocol for data collection, preparation, and analysis. We used mixed effects linear models for analyses of fecundity, Cormack-Jolly-Seber open population models for analyses of apparent annual survival (/), and a reparameterization of the Jolly-Seber capture-recapture model (i.e. reverse Jolly-Seber; RJS) to estimate annual rates of population change (k RJS ) and recruitment. We also modeled territory occupancy dynamics of Northern Spotted Owls and Barred Owls in each study area using 2-species occupancy models. Estimated mean annual rates of population change (k) suggested that Spotted Owl populations declined from 1.2% to 8.4% per year depending on the study area. The weighted mean estimate of k for all study areas was 0.962 (6 0.019 SE; 95% CI: 0.925-0.999), indicating an estimated range-wide decline of 3.8% per year from 1985 to 2013. Variation in recruitment rates across the range of the Spotted Owl was best explained by an interaction between total winter precipitation and mean minimum winter temperature. Thus, recruitment rates were highest when both total precipitation (29 cm) and minimum winter temperature (À9.58C) were lowest. Barred Owl presence was associated with increased local extinction rates of Spotted Owl pairs for all 11 study areas. Habitat covariates were related to extinction rates for Spotted Owl pairs in 8 of 11 study areas, and a greater amount of suitable owl habitat was generally associated with decreased extinction rates. We observed negative effects of Barred Owl presence on colonization rates of Spotted Owl pairs in 5 of 11 study areas. The total amount of suitable Spotted Owl habitat was positively associated with colonization rates in 5 areas, and more habitat disturbance was associated with lower colonization rates in 2 areas. We observed strong declines in derived estimates of occupancy in all study areas. Mean fecundity of females was highest for adults (0.309 6 0.027 SE), intermediate for 2-yr-olds (0.179 6 0.040 SE), and lowest for 1-yr-olds (0.065 6 0.022 SE). The presence of Barred Owls and habitat covariates explained little of the temporal variation in fecundity in most study areas. Climate covariates ...

Population connectivity between resident and migratory cutthroat trout (Oncorhynchus clarkii ssp.) is understudied, but has implications for population viability and management. We examined evidence for stream residency, studied the spatial patterns of stream use by adfluvial and stream-resident trout, and measured migration rates with changing stream depth for Lahontan cutthroat trout (Oncorhynchus clarkii henshawi) in the Summit Lake Basin, Nevada (USA). Passive integrated transponder technology and a fry trap were used to track fish movements and identify the distribution of resident and adfluvial trout. Stream residents were distributed throughout the network. Adfluvial spawners concentrated in lower reaches, but also migrated up to 12.9 km. Adfluvial juveniles migrated to the lake from lower reaches and from upstream of adfluvial spawners. High stream depths coincided with more adfluvial juveniles migrating to the lake and more adfluvial spawners moving into the stream, which led to more accessing the upper watershed. This work shows that connectivity is central to adfluvial–resident Lahontan cutthrout trout population dynamics and may lead to increased probability of persistence — a characteristic of these isolated, threatened trout populations.

Summit Lake, nevada (USA) is the last high-desert terminal lake to have a native self-sustaining population of threatened Lahontan cutthroat trout (Oncorhynchus clarkii henshawi). from spring 2015 to fall 2017, we quantified adult abundance and survival and the total annual spawning run. Abundance and survival were estimated with mark-recapture using pit tags, and the annual spawning run was estimated with PIT tag detections and counts of spawners. Adult abundance fluctuated from 830 (95% CI 559-1248) to 1085 (95% CI 747-1614), with no overall temporal trend, as a decrease in male abundance was generally offset by an equal increase in female abundance. Estimated mean adult survival was 0.51 (95% CI 0.44-0.58). The spawning run increased from 645 (2015) to 868 (2016), but then decreased slightly to 824 (2017, mean = 789 ± 118). Female spawners increased in 2016 but decreased slightly in 2017, whereas male spawners decreased each year. In addition, the proportion of adults that spawned each year increased overall. our study suggests that the adult population remained stable although most of the study period included the recent, severe regional drought in the western United States (2012-2016). Amid the backdrop of global biodiversity decline, North American freshwater fauna is declining five times faster than terrestrial fauna, including current extinction rates of freshwater fish 877 times greater than background rates 1-3. Since the mid-1800s, habitat loss, overfishing and invasive species have severely altered western United States (US) freshwater fish communities 4. Today climate change predictions for the large expanse of mountain ranges in the western US (increased climatic variability that will increase drought frequency, duration, and severity, and shift precipitation to more rain and less snow) threaten to compound the above disturbances 5-8. These legacy, current and future disturbances combine into a formidable challenge for conserving western US freshwater fish biodiversity, often necessitating active management of fisheries that are susceptible to further decline and localized extinctions 9. Cutthroat trout (Oncorhynchus clarkii spp.) are salmonids native to the coastal and inland waters of western North America 10. Consisting originally of approximately 14 subspecies, the historic distribution of cutthroat species ranged from Alaska to southern Texas and the Pacific coast to the Rocky Mountains 10,11. Distribution and abundance of many subspecies have declined over the past century. Two subspecies are extinct and three subspecies are on the US endangered species list 10,12. Cutthroat trout population dynamics research has been concentrated in the rivers and streams of the Rocky Mountains, the eastern side of the Intermountain Region (area between the Sierra Nevada/Cascade Mountains and the Rocky Mountains), and the Sierra Nevada Mountains 13-24. Little is known about the population dynamics of cutthroat trout in lakes across the western US, especially the desert terminal mountain lakes of the Great Bas...