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The California spotted owl (Strix occidentalis occidentalis) is an older‐forest associated species that resides at the center of forest management planning in the Sierra Nevada and Southern California, USA, which are experiencing increasingly large and severe wildfires and drought‐related tree mortality. We leveraged advances in passive acoustic survey technologies to develop an acoustically assisted survey design that could increase the efficiency and effectiveness of project‐level surveys for spotted owls, allowing surveys to be completed in a single year instead of in multiple years. We deployed an array of autonomous recording units (ARUs) across a landscape and identified spotted owl vocalizations in the resulting audio using BirdNET. We then evaluated spatio‐temporal patterns in spotted owl vocalizations near occupied territories and the ability of a crew naïve to the location of occupied territories to locate spotted owls based on patterns of acoustic detections. After only 3 weeks of acoustic surveys, ≥1 ARU within 750 m of all 17 occupied territories obtained spotted owl detections across ≥2 nights. When active surveys using broadcast calling were conducted near ARUs with spotted owl detections by surveyors naïve to territory occupancy status and locations, surveyors located owls in 93% to 100% of occupied territories with ≤3 surveys. To further improve the efficiency of spotted owl surveys, we developed a statistical model to identify and prioritize areas across the Sierra Nevada for different survey methods (active only, acoustically assisted, no surveys) based on the expected probability of occupancy predicted from remotely sensed measurements of tree height and historical occupancy. Depending on managers' tolerance for false negatives, this model could help identify large areas that might not benefit from surveys based on low expected occupancy probabilities and areas where acoustically assisted surveys might enhance survey effectiveness and efficiency. Collectively, these findings can help managers streamline the survey process and thus increase the pace of forest restoration while minimizing potential near‐term adverse effects on California spotted owls. [ABSTRACT FROM AUTHOR]

Predator populations are imperiled globally, due in part to changing habitat and trophic interactions. Theoretical and laboratory studies suggest that heterogeneous landscapes containing prey refuges acting as source habitats can benefit both predator and prey populations, although the importance of heterogeneity in natural systems is uncertain. Here, we tested the hypothesis that landscape heterogeneity mediates predator–prey interactions between the California spotted owl (Strix occidentalis occidentalis)—a mature forest species—and one of its principal prey, the dusky‐footed woodrat (Neotoma fuscipes)—a younger forest species—to the benefit of both. We did so by combining estimates of woodrat density and survival from live trapping and very high frequency tracking with direct observations of prey deliveries to dependent young by owls in both heterogeneous and homogeneous home ranges. Woodrat abundance was ~2.5 times higher in owl home ranges (14.12 km2) featuring greater heterogeneity in vegetation types (1805.0 ± 50.2 SE) compared to those dominated by mature forest (727.3 ± 51.9 SE), in large part because of high densities in young forests appearing to act as sources promoting woodrat densities in nearby mature forests. Woodrat mortality rates were low across vegetation types and did not differ between heterogeneous and homogeneous home ranges, yet all observed predation by owls occurred within mature forests, suggesting young forests may act as woodrat refuges. Owls exhibited a type 1 functional response, consuming ~2.5 times more woodrats in heterogeneous (31.1/month ± 5.2 SE) versus homogeneous (12.7/month ± 3.7 SE) home ranges. While consumption of smaller‐bodied alternative prey partially compensated for lower woodrat consumption in homogeneous home ranges, owls nevertheless consumed 30% more biomass in heterogeneous home ranges—approximately equivalent to the energetic needs of producing one additional offspring. Thus, a mosaic of vegetation types including young forest patches increased woodrat abundance and availability that, in turn, provided energetic and potentially reproductive benefits to mature forest‐associated spotted owls. More broadly, our findings provide strong empirical evidence that heterogeneous landscapes containing prey refuges can benefit both predator and prey populations. As anthropogenic activities continue to homogenize landscapes globally, promoting heterogeneous systems with prey refuges may benefit imperiled predators. [ABSTRACT FROM AUTHOR]

Spatial and temporal variation in fire characteristics—termed pyrodiversity—are increasingly recognized as important factors that structure wildlife communities in fire‐prone ecosystems, yet there have been few attempts to incorporate pyrodiversity or post‐fire habitat dynamics into predictive models of animal distributions and abundance to support post‐fire management. We use the black‐backed woodpecker—a species associated with burned forests—as a case study to demonstrate a pathway for incorporating pyrodiversity into wildlife habitat assessments for adaptive management. Employing monitoring data (2009–2019) from post‐fire forests in California, we developed three competing occupancy models describing different hypotheses for habitat associations: (1) a static model representing an existing management tool, (2) a temporal model accounting for years since fire, and (3) a temporal–landscape model which additionally incorporates emerging evidence from field studies about the influence of pyrodiversity. Evaluating predictive ability, we found superior support for the temporal–landscape model, which showed a positive relationship between occupancy and pyrodiversity and interactions between habitat associations and years since fire. We incorporated the new temporal–landscape model into an RShiny application to make this decision‐support tool accessible to decision‐makers. [ABSTRACT FROM AUTHOR]

Mountain ecosystems contain strong elevational gradients in climate and vegetation that shape species distributions and the structure of animal communities. Nevertheless, studies of habitat selection for individual species rarely account for such gradients that often result in species being managed uniformly across their range, which may not improve conservation as intended. Therefore, we characterized variation in nocturnal habitat selection by 18 GPS‐tagged California spotted owls (Strix occidentalis occidentalis) along a 1400‐m elevational gradient in the Sierra Nevada, California. We characterized three‐dimensional forest structure with light detection and ranging data that we used in mixed‐effects resource‐ and step‐selection analyses of owl habitat selection. At lower elevations, owls selected stands with shorter trees, sites closer to hard edges between tall forests and open areas, sites with less diversity in forest seral types and sites with more ridge and southwest aspects. In contrast, owls at higher elevations selected the opposite. Within public forests that had taller trees and within their home range core (45% kernel density estimate of GPS points) areas, owls selected forests with less and more canopy cover at low and high elevations, respectively. Outside of their core areas, owls selected areas with fewer and more tall trees at low and high elevations, respectively. These findings may be explained by elevational gradients in prey distribution and variation in owl diet because owls consume more woodrats (Neotoma spp; earlier seral species) at lower elevations and more flying squirrels (Glaucomys sabrinus; older forest species) at higher elevations. Thus, at low elevations and in areas unlikely to support nesting, spotted owls could benefit from management that promotes woodrat habitat by encouraging oak regeneration and creating small brushy openings within forests with shorter (younger) trees. Conversely, at higher elevations, (1) enhancing flying squirrel habitat by promoting large trees and denser canopy on mesic sites and (2) managing for greater cover type diversity on southwest‐facing slopes and ridgetops is more likely to improve foraging habitat quality for spotted owls. The patterns of owl selection over elevational gradients has not been explicitly considered in most habitat management plans but clearly would improve management throughout mountain ecosystems. [ABSTRACT FROM AUTHOR]

Highlights • We studied habitat selection of GPS-tagged California spotted owls in mixed-ownership forests. • Spotted owls selected forests with intermediate- to larger-sized trees with canopy > 50%for foraging. • Cover type explained habitat selection better than landownership type. • Privately-owned lands harbored more suitable spotted owl habitat than previously recognized. • Collaborative research can benefit conservation in mixed-ownership landscapes. Abstract The relative contribution of private and public forest to the conservation of species in mixed-ownership landscapes has often been contentious because management goals vary among owners. This tension can be exacerbated by a lack of understanding about how wildlife use habitats managed by different landowners and the relative value of habitats in having different structures, configurations, and management histories. To address this knowledge gap and enhance science-based conservation planning among different ownerships, we analyzed habitat selection by 53 GPS-tagged California spotted owls across multiple temporal scales within mixed-ownership landscapes in the Sierra Nevada. At a fine temporal scale, step-selection function analysis of hourly locations collected by GPS tags suggested that foraging spotted owls selected closed-canopy, larger-tree forest (Quadratic Mean Diameter [QMD] ≥ 33 cm, canopy cover ≥ 60%). Point selection function (PSF) analysis based on single nightly locations suggested that spotted owls selected a broader range of forest conditions including selection of forests having intermediate sized trees and intermediate canopy cover (QMD 28–33 cm, canopy cover ≥ 50%), and the strength of selection for these forest conditions increased in the less frequently used areas of home ranges. The PSF also suggested that spotted owls selected areas with relatively high cover type heterogeneity that included a mix of seral stages, except in the core of their home range where they selected relatively spatially homogenous forests characterized by large trees and closed canopy. Spotted owl home ranges increased in size with increasing elevation and cover type heterogeneity, and decreased in size with forest characterized by intermediate-sized trees. Collectively, these results indicate that landscapes having forest patches characterized by either intermediate or large-sized trees, both with high canopy cover, likely constitute the important foraging habitat for California spotted owls in Sierra Nevada mixed conifer forests. However, selection for any one particular cover type was not sufficiently strong for us to infer selection of individual landownership types, in spite of differences in forest conditions among ownerships. Collectively, our findings suggest that privately-owned lands used in our study may harbor more suitable spotted owl foraging habitat than previously recognized. Finally, given the importance of understanding the relationship between landowner management priorities and the resultant pattern of vegetation on lands with different ownerships, the development of forest management strategies relevant for broad-scale conservation of the Sierra Nevada forest will benefit from effective collaboration between forest managers, landowners, and research organizations. [ABSTRACT FROM AUTHOR]