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Reviews a research project in which, using library and computer resources, students compiled a comparison profile of selected physical, social, and economic characteristics of Morocco and California. The students evaluated the relative role of environmental variables in influencing the human geography of the two regions. (MJP)

The Coastal California Gnatcatcher (Polioptila californica californica), a federally threatened species, is a flagship species for regional conservation planning in southern California (USA). An inhabitant of coastal sage scrub vegetation, the gnatcatcher has declined in response to habitat loss and fragmentation, exacerbated by catastrophic wildfires. We documented the status of gnatcatchers throughout their California range and examined post-fire recovery of gnatcatchers and their habitat. We used GIS to develop a habitat suitability model for Coastal California Gnatcatchers using climate and topography covariates and selected over 700 sampling points in a spatially balanced manner. Bird and vegetation data were collected at each point between March and May in 2015 and 2016. Presence/absence of gnatcatchers was determined during three visits to points, using area searches within 150 x 150 m plots. We used an occupancy framework to generate Percent Area Occupied (PAO) by gnatcatchers, and analyzed PAO as a function of time since fire. At the regional scale in 2016, 23% of the points surveyed were occupied by gnatcatchers, reflecting the effect of massive wildfires in the last 15 years. Similarly, PAO in the post-fire subset of points was 24%, with the highest occupancy in unburned (last fire <2002) habitat. Positive predictors of occupancy included percent cover of California sagebrush (Artemisia californica), California buckwheat (Eriogonom fasciculatum), and sunflowers (Encelia spp., Bahiopsis laciniata), while negative predictors included laurel sumac (Malosma laurina) and total herbaceous cover; in particular, non-native grasses. Our findings indicate that recovery from wildfire may take decades, and provide information to speed up recovery through habitat restoration. [ABSTRACT FROM AUTHOR]

Chinook salmon (Oncorhynchus tshawytscha) display remarkable life history diversity, underpinning their ability to adapt to environmental change. Maintaining life history diversity is vital to the resilience and stability of Chinook salmon metapopulations, particularly under changing climates. However, the conditions that promote life history diversity are rapidly disappearing, as anthropogenic forces promote homogenization of habitats and genetic lineages. In this study, we use the highly modified Yuba River in California to understand if distinct genetic lineages and life histories still exist, despite reductions in spawning habitat and hatchery practices that have promoted introgression. There is currently a concerted effort to protect federally listed Central Valley spring‐run Chinook salmon populations, given that few wild populations still exist. Despite this, we lack a comprehensive understanding of the genetic and life history diversity of Chinook salmon present in the Yuba River. To understand this diversity, we collected migration timing data and GREB1L genotypes from hook‐and‐line, acoustic tagging, and carcass surveys of Chinook salmon in the Yuba River between 2009 and 2011. Variation in the GREB1L region of the genome is tightly linked with run timing in Chinook salmon throughout their range, but the relationship between this variation and entry on spawning grounds is little explored in California's Central Valley. We found that the date Chinook salmon crossed the lowest barrier to Yuba River spawning habitat (Daguerre Point Dam) was tightly correlated with their GREB1L genotype. Importantly, our study confirms that ESA‐listed spring‐run Chinook salmon are spawning in the Yuba River, promoting a portfolio of life history and genetic diversity, despite the highly compressed habitat. This work highlights the need to identify and protect this life history diversity, especially in heavily impacted systems, to maintain healthy Chinook salmon metapopulations. Without protection, we run the risk of losing the last vestiges of important genetic variation. [ABSTRACT FROM AUTHOR]

We combined two climate‐based distribution models with three finer‐scale suitability models to identify habitat for pronghorn recovery in California now and into the future. We used a consensus approach to identify areas of suitable climate now and future for pronghorn in California. We compared the results of climate models from two separate hypotheses about their historical ecology in the state. Under the migration hypothesis, pronghorn were expected to be limited climatically by extreme cold in winter and extreme heat in summer; under the niche reduction hypothesis, historical pronghorn of distribution would have better represented the climatic limitations of the species. We combined occurrences from GPS collars distributed across three populations of pronghorn in the state to create three distinct habitat suitability models: (1) an ensemble model using random forests, Maxent, classification and regression Trees, and a generalized linear model; (2) a step selection function; and (3) an expert‐driven model. We evaluated consensus among both the climate models and the suitability models to prioritize areas for, and evaluate the prospects of, pronghorn recovery. Climate suitability for pronghorn in the future depends heavily on model assumptions. Under the migration hypothesis, our model predicted that there will be no suitable climate in California in the future. Under the niche reduction hypothesis, by contrast, suitable climate will expand. Habitat suitability also depended on the methods used, but areas of consensus among all three models exist in large patches throughout the state. Identifying habitat for a species which has undergone extreme range collapse, and which has very fine scale habitat needs, presents novel challenges for spatial ecologists. Our multimethod, multihypothesis approach can allow habitat modelers to identify areas of consensus and, perhaps more importantly, fill critical knowledge gaps that could resolve disagreements among the models. For pronghorn, a better understanding of their upper thermal tolerances and whether historical populations migrated will be crucial to their potential recovery in California and throughout the arid Southwest. [ABSTRACT FROM AUTHOR]

Joshua trees (Yucca brevifolia) are a keystone species that provide habitat for many animals, including desert night lizards (Xantusia vigilis), which are highly reliant on fallen Joshua tree logs for habitat. In the near future, climate change will likely negatively affect Joshua trees, and by extension desert night lizards, but little work has been done to characterize X. vigilis habitat in more detail and predict how it will be affected. In this study, we measured the sizes of living and dead Joshua trees at Saddleback Butte State Park in the California Mojave Desert and quantified the amount of habitat they produced. The majority of X. vigilis habitat is produced by living trees estimated to be over 120 years old and equally long-lived dead trees. In addition, trees might only produce high-quality habitat (earlier decay stages) for a small percentage of lifetime and about a third of the decay process. These results suggest that a reduction in Joshua tree recruitment or lifespan would have negative consequences for desert night lizards. However, the impacts on desert night lizards are likely to occur long after the change in the Joshua tree population. [ABSTRACT FROM AUTHOR]

Macrolichen diversity and community composition were determined for an area of high botanical interest in the Coast Ranges of Northern California – the Horse Mountain Botanical Area (HMBA) in Six Rivers National Forest. The Coast Ranges have been suggested to have high lichen diversity, yet detailed site-specific macrolichen surveys are lacking for the area. The HMBA is characterized by the presence of ultramafic (serpentine) soils, contributing to its diverse assemblage of conifers. Here we present comprehensive data on macrolichens of the HMBA integrated with environmental variables at the landscape level. Twenty 0.4 ha sampling plots were positioned across the varying habitats of the HMBA and macrolichens were intensively sampled from all substrata. Out of 888 total collections, 119 macrolichen species in 52 genera were identified, 63 species were sequenced for the mycobiont internal transcribed spacer (ITS) region, and all species were vouchered. Microenvironmental influences on lichen community composition were ordinated with nonmetric multidimensional scaling (NMS). Within-plot measured environmental variables with strongest correlations to ordination Axis 1 were 1) total tree basal area, 2) proportion of conifer basal area relative to hardwoods, and 3) distance between plot center and nearest stream. Distinct macrolichen communities were found in plots containing primarily conifers versus mixed hardwood-conifer plots. All plots contained both nitrogen-fixing and pendulous forage macrolichens; in each of the three hardwood-dominated plots, nitrogen-fixing lichens composed nearly a third of the species total. When epiphytic macrolichen species richness and dominance within the HMBA were compared to data from other regional forests, the HMBA showed comparable community composition but averaged 39% higher species richness. Results from this study can help inform management of the HMBA as well as future taxonomic and ecological research on regional macrolichens. [ABSTRACT FROM AUTHOR]

Quantifiable measurement of habitat restoration effects on salmonid reproductive performance is limited, although it is necessary for evaluating whether population responses follow management actions. We investigated using close‐kin mark‐recapture methods to partition restoration effects within standard monitoring metrics of juvenile emigrants leaving the natal reach. This approach allowed for statistical comparison of relative juvenile capture rates (recruitment) from Chinook Salmon (Oncorhynchus tshawytscha) naturally reproducing in gravel augmented (restored) and nonaugmented (unrestored) reaches of a highly managed California River. Genetic parentage techniques linked adult females that had spawned in augmented and nonaugmented spawning habitats with juvenile Chinook Salmon sampled the following spring at a trap located below the natal spawning area. Successful recruitment was documented from both augmented and nonaugmented habitats, with no statistical difference between the two habitat types. The capture rate per adult female was low (0.19–0.24 juveniles/female) compared to rates observed in other systems. Within the juvenile collections, most females in the study had 0 or 1 offspring observed; however, one female that spawned in a restored habitat had 25 offspring recovered at the trap. We modeled juvenile capture rates in relation to a range of biological and environmental variables including spawning habitat site, spawning habitat treatment (augmented and nonaugmented), annual spawner abundance, year spawned, female fork length, spawning and hatch day, and flow maximum and variance. There was an inverse relationship between annual adult abundance (escapement obtained from carcass surveys) and recruitment (juvenile recoveries at trap), suggesting habitat limitation may be creating density‐dependent effects. Additionally, female body size was positively associated with recruitment, while spawning day and mean daily temperature were inversely associated with recruitment, suggesting that both biological and environmental factors independent of habitat influenced reproduction potential. This study provides evidence that habitat restoration could have an additive (incremental) positive effect on recruitment rate, informing hatchery management and restoration activities related to population recovery. [ABSTRACT FROM AUTHOR]

Aim: As climate change increases the frequency and severity of droughts in many regions, conservation during drought is becoming a major challenge for ecologists. Droughts are multidimensional climate events whose impacts may be moderated by changes in temperature, water availability or food availability, or some combination of these. Simultaneously, other stressors such as extensive anthropogenic landscape modification may synergize with drought. Useful observational models for guiding conservation decision‐making during drought require multidimensional, dynamic representations to disentangle possible drought impacts, and consequently, they will require large, highly resolved data sets. In this paper, we develop a two‐stage predictive framework for assessing how drought impacts vary with species, habitats and climate pathways. Location: Central Valley, California, USA. Methods: We used a two‐stage counterfactual analysis combining predictive linear mixed models and N‐mixture models to characterize the multidimensional impacts of drought on 66 bird species. We analysed counts from the eBird participatory science data set between 2010 and 2019 and produced species‐ and habitat‐specific estimates of the impact of drought on relative abundance. Results: We found that while fewer than a quarter (16/66) of species experienced abundance declines during drought, nearly half of all species (27/66) changed their habitat associations during drought. Among species that shifted their habitat associations, the use of natural habitats declined during drought while use of developed habitat and perennial agricultural habitat increased. Main Conclusions: Our findings suggest that birds take advantage of agricultural and developed land with artificial irrigation and heat‐buffering microhabitat structure, such as in orchards or parks, to buffer drought impacts. A working lands approach that promotes biodiversity and mitigates stressors across a human‐induced water gradient will be critical for conserving birds during drought. [ABSTRACT FROM AUTHOR]

Cool‐water habitats provide increasingly vital refuges for cold‐water fish living on the margins of their historical ranges; consequently, efforts to enhance or create cool‐water habitat are becoming a major focus of river restoration practices. However, the effectiveness of restoration projects for providing thermal refuge and creating diverse temperature regimes at the watershed scale remains unclear. In the Klamath River in northern California, the Karuk Tribe Fisheries Program, the Mid‐Klamath Watershed Council, and the U.S. Forest Service constructed a series of off‐channel ponds that recreate floodplain habitat and support juvenile coho salmon (Oncorhynchus kisutch) and steelhead (O. mykiss) along the Klamath River and its tributaries. We instrumented these ponds and applied multivariate autoregressive time series models of fine‐scale temperature data from ponds, tributaries, and the mainstem Klamath River to assess how off‐channel ponds contributed to thermal regime diversity and thermal refuge habitat in the Klamath riverscape. Our analysis demonstrated that ponds provide diverse thermal habitats that are significantly cooler than creek or mainstem river habitats, even during severe drought. Wavelet analysis of long‐term (10 years) temperature data indicated that thermal buffering (i.e. dampening of diel variation) increased over time but was disrupted by drought conditions in 2021. Our analysis demonstrates that in certain situations, human‐made off‐channel ponds can increase thermal diversity in modified riverscapes even during drought conditions, potentially benefiting floodplain‐dependent cold‐water species. Restoration actions that create and maintain thermal regime diversity and thermal refuges will become an essential tool to conserve biodiversity in climate‐sensitive watersheds. [ABSTRACT FROM AUTHOR]

The previously unknown female of Psilochorus inyoSlowik, 2009 is described and illustrated. Determination of the species was validated using DNA barcoding as well as collection occurrences. Collection data for females collected in northeastern California and information on the species habitat and distribution are provided. [ABSTRACT FROM AUTHOR]

An animal's movement is influenced by a plethora of internal and external factors, leading to individual‐ and habitat‐specific movement characteristics. This plasticity is thought to allow individuals to exploit diverse environments efficiently. We tested whether the movement characteristics of white sharks Carcharodon carcharias differ across ontogeny and among habitats along the coast of Central California. In doing so, we elucidate how changes in internal state (physiological changes coinciding with body size) and external environments (differing seascapes and/or diel phases) shape the movement of this globally distributed predator. Twenty‐one white sharks, from small juveniles to large adults, were equipped with motion‐sensitive biologging tags at four contrasting seascapes: two islands, a headland, and an inshore cove. From multisensor biologging data, 20 metrics characterizing movement (i.e., depth use, vertical velocities, activity, turning rates, and bursting events) were derived and subjected to multivariate analyses. Movement characteristics were most different across seascapes, followed by ontogeny and diel phase. Juvenile sharks, which were only encountered at the cove, displayed the most distinct movement characteristics. Sharks at this seascape remained close to the shore traveling over smaller areas, shallower depth ranges, and with lower levels of tail beat frequencies, when corrected for size, than sub‐adult and adult sharks tagged elsewhere. Distinct tortuous daytime versus linear nighttime horizontal movements were recorded from sharks at island seascapes but not from those at the headland or inshore cove. At the offshore islands, the linear nighttime swimming patterns coincided with repeated dives to and from deeper water. The availability of prey and access to deeper water are likely drivers of the differences in movement characteristics described, with varying demographics of pinniped prey found at the subadult and adult aggregation areas and juvenile sharks being piscivorous and their habitat neither adjacent to pinniped haul out areas nor deeper water. This study demonstrates plasticity in the movements of a top predator, which adapts its routine to suit the habitat it forages within. [ABSTRACT FROM AUTHOR]

The world is urbanizing rapidly, resulting in increasing rates of habitat loss and fragmentation. Protected areas are commonly established to restrict development and conserve native ecological communities. Yet urban protected areas often receive high levels of recreational activity, which can reduce their conservation effectiveness because of disturbance to animals. Recreation has negative consequences for many animal species, but its effects on reptiles are largely unknown. We evaluated the effects of non-consumptive recreation on reptiles within urban protected areas in a fragmented landscape in coastal southern California, USA. We surveyed lizards and snakes along a gradient of recreation intensity and modeled species richness, community composition, and occupancy in relation to human activity along with other variables known to affect reptile distributions. We observed a decline in lizard species richness in association with human activity. Richness of habitat specialists was not related to recreation, but smaller-bodied lizards and lizards with narrower active temperature ranges were less common at sites with high human activity. Human activity was associated with a decline in occupancy of the common side-blotched lizard (Uta stansburiana), no meaningful relationship with occupancy of the orange-throated whiptail (Aspidoscelis hyperythra) and a positive relationship with western fence lizard (Sceloporus occidentalis) occupancy and/or detection probability. Our study demonstrates that increasing rates of recreation activity can reduce the ability of urban protected areas to conserve diverse reptile assemblages. [ABSTRACT FROM AUTHOR]

Light detection and ranging (lidar) has emerged as a valuable tool for examining the fine‐scale characteristics of vegetation. However, lidar is rarely used to examine coastal wetland vegetation or the habitat selection of small mammals. Extensive anthropogenic modification has threatened the endemic species in the estuarine wetlands of the California coast, such as the endangered salt marsh harvest mouse (Reithrodontomys raviventris; SMHM). A better understanding of SMHM habitat selection could help managers better protect this species. We assessed the ability of airborne topographic lidar imagery in measuring the vegetation structure of SMHM habitats in a coastal wetland with a narrow range of vegetation heights. We also aimed to better understand the role of vegetation structure in habitat selection at different spatial scales. Habitat selection was modeled from data compiled from 15 small mammal trapping grids collected in the highly urbanized San Francisco Estuary in California, USA. Analyses were conducted at three spatial scales: microhabitat (25 m2), mesohabitat (2025 m2), and macrohabitat (~10,000 m2). A suite of structural covariates was derived from raw lidar data to examine vegetation complexity. We found that adding structural covariates to conventional habitat selection variables significantly improved our models. At the microhabitat scale in managed wetlands, SMHM preferred areas with denser and shorter vegetation and selected for proximity to levees and taller vegetation in tidal wetlands. At the mesohabitat scale, SMHM were associated with a lower percentage of bare ground and with pickleweed (Salicornia pacifica) presence. All covariates were insignificant at the macrohabitat scale. Our results suggest that SMHM preferentially selected microhabitats with access to tidal refugia and mesohabitats with consistent food sources. Our findings showed that lidar can contribute to improving our understanding of habitat selection of wildlife in coastal wetlands and help to guide future conservation of an endangered species. [ABSTRACT FROM AUTHOR]

Forest managers working in dry forest ecosystems must contend with the costs and benefits of fire, and they are seeking forest management strategies that enhance the resilience of forests and landscapes to future disturbances in a changing climate. An interdisciplinary science team worked with resource managers and stakeholders to assess future forest ecosystem dynamics, given potential climatic changes and management strategies, across a 23,000-ha landscape in the Lake Tahoe basin of California and Nevada in support of the Lake Tahoe West Restoration Partnership. We projected forest growth and fire dynamics using a landscape change model, upon which the science team layered additional modeling to evaluate changes in wildlife habitat, water, and economics. Managers and stakeholders used the findings of this integrated modeling effort to inform the design of a landscape restoration strategy that balanced risks and benefits based on a robust scientific foundation. The results, published in this Special Feature, suggest that a continuation of status quo management would be less effective at protecting and improving desired outcomes than more active and extensive management approaches. In addition, the types of management activity also affected ecosystem outcomes. Results from across the studies in this special feature suggest that thinning and prescribed fire were complementary, although they resulted in somewhat different effects, and that low-severity use of fire had the greatest array and magnitude of ecosystem benefits. A notable exception was carbon storage, which declined with more active management and prescribed fire in particular. We highlight key findings from this Special Feature and summarize key challenges and some lessons learned in our experience of co-producing science. In short, science-management partnerships require cooperation, patience, and skill, but they are effective in increasing the capacity of land managers to navigate in an environment of rapid change and increasing uncertainty. [ABSTRACT FROM AUTHOR]

Novel wildfire regimes are rapidly changing global ecosystems and pose significant challenges for biodiversity conservation and ecosystem management. In this study, we used DNA metabarcoding to assess the response of arthropod pollinator communities to large‐scale wildfires across diverse habitat types in California. We sampled six reserves within the University of California Natural Reserve System, each of which was partially burned in the 2020 Lightning Complex wildfires in California. Using yellow pan traps to target pollinators, we collected arthropods from burned and unburned sites across multiple habitat types including oak woodland, redwood, scrub, chamise, grassland, forest, and serpentine habitats. We found no significant difference in alpha diversity values between burned and unburned sites; instead, seasonal variations played a significant role in arthropod community dynamics, with the emergence of plant species in Spring promoting increased pollinator richness at all sites. When comparing all sites, we found that burn status was not a significant grouping factor. Instead, compositional differences were largely explained by geographic differences, with distinct communities within each reserve. Within a geographic area, the response of arthropods to fire was dependent on habitat type. While communities in grasslands and oak woodlands exhibited recovery following burn, scrublands experienced substantial changes in community composition. Our study highlights the importance of examining community responses to wildfires across broad spatial scales and diverse habitat types. By understanding the nuanced dynamics of arthropod communities in response to fire disturbances, we can develop effective conservation strategies that promote resilience and maintain biodiversity in the face of increasing wildfire frequency and severity driven by climate change. [ABSTRACT FROM AUTHOR]

Fire activity during 2020 to 2021 in California, USA, was unprecedented in the modern record. More than 19,000 km2 of forest vegetation burned (10× more than the historical average), potentially affecting the habitat of 508 vertebrate species. Of the >9,000 km² that burned at high severity, 89% occurred in large patches that exceeded historical estimates of maximum high-severity patch size. In this 2-y period, 100 vertebrate species experienced fire across >10% of their geographic range, 16 of which were species of conservation concern. These 100 species experienced high-severity fire across 5 to 14% of their ranges, underscoring potentially important changes to habitat structure. Species in this region are not adapted to high-severity megafires. Management actions, such as prescribed fires and mechanical thinning, can curb severe fire behavior and reduce the potential negative impacts of uncharacteristic fires on wildlife. [ABSTRACT FROM AUTHOR]

Herein a new species of Paruroctonus Werner, 1934 is described from alkali-sink habitats in the San Joaquin Desert of central California, Paruroctonus tulare sp. nov. It can be differentiated from other Paruroctonus by a combination of morphological features including scalloped pedipalp fingers in males, specific setal counts and morphometric ratios, and specific patterns of fuscous pigmentation. It also inhabits a unique distribution allopatric with all other Paruroctonus species except P. variabilis Hjelle, 1982. Photographs of a large series of live P. tulare sp. nov. from across their range and detailed images of several morphological features are provided, their distribution is modeled, a haplotype network is presented, and details about their habitat, ecology, and conservation are discussed. [ABSTRACT FROM AUTHOR]

The distribution and abundance of demersal young of the year (YOY) of rockfish species (Sebastes spp.) were investigated over a 17-year period along the central coast of California at depths of 19-326 m. More than 87,000 YOY rockfish were counted during surveys of 1292 transects on the seafloor. The 3 most abundant species were the pygmy (S. wilsoni), halfbanded (S. semicinctus), and shortbelly (S. jordani) rockfish. Young of the year of many rockfishes were found at greater depths than have been previously reported. The highest densities of all species combined occurred in shallow and intermediate depths (=100 m). Most YOY rockfish occupied rock or mixed substrata, except the greenstriped (S. elongatus) and stripetail (S. saxicola) rockfish, which were associated primarily with soft substrata. Statistically significant (P<0.01) hot spots of YOY rockfish densities were located throughout the region, but only Soquel Canyon, a known refuge for large adult rockfish (>50 cm in total length), was a significant (P<0.01) cold spot. Biological processes (e.g., ontogenetic movement and predation) and environmental characteristics (e.g., seafloor habitat and oceanographic conditions) are potential influences on the distribution of YOY of rockfishes. The results of our study provide insights into the distributions of YOY of rockfishes in deep, complex seafloor habitats and can help improve estimation of year-class strength through targeted surveys of preferred habitats. [ABSTRACT FROM AUTHOR]

The San Joaquin antelope squirrel (Ammospermophilus nelsoni; SJAS) is a state-listed Threatened species in California that evolved in the shrublands of the San Joaquin Desert. Due to livestock overgrazing and fires, much of the desert has lost its shrub cover, which would be a conservation concern if shrubs are a necessary component of the habitat for squirrels. We established two 64-trap plots on the Lokern area of Kern County, California: one covered by saltbush scrub (Atriplex spp.) and another nearby without shrubs. We trapped quarterly starting in January 2019 and ending in November 2021 (12 trap sessions). When a squirrel was found in a trap, we permanently marked it with a passive inte¬grated transponder (PIT) tag, recorded its trap location on the plot, and assessed its sex, weight (using a spring scale), age (young or adult), and reproductive condition. In the 3 years of trapping, we marked 90 SJAS on the shrub plot and 194 on the shrubless plot. On both plots, numbers of squirrels trended upward for the 3 years, with significantly higher numbers of SJAS on the shrubless plot in 2021. Survivorship did not differ significantly between plots, but we recorded more young squirrels on the shrubless plot. Although our plots were not replicated, our results and those of recent other studies show that shrubs are not a necessary component of the habitat for SJAS. [ABSTRACT FROM AUTHOR]

Simple Summary: Urban sprawl contributes to biodiversity loss, but the presence of native plants in urban areas may help to support diversity. In urban gardens, where non-native plants are common, the role of native plants may be especially important in providing resources to pollinators and other beneficial arthropods, like natural enemies of pests, but little research has examined how native plants affect non-pollinators in gardens. We sampled plants, bees, and three groups of natural enemies (ladybeetles, ants, and ground-foraging spiders) in gardens in California. We found that native plants represented about 10% of the species and only 2.5% of the plants found. The native plants present did not have large impacts on the numbers or diversity of bees, ladybeetles, or ants, but did have an unexpected negative effect on non-native spiders. Other garden features, such as garden size, flowers, mulch, and trees and shrubs, did have mostly positive impacts on the biodiversity of bees, ants, and spiders, but the impacts of each feature differed by organism type. Natural habitat near to gardens was also important for native ants, non-native bees, and ladybeetles. In sum, native plants, when rare within gardens, likely have little benefit, but other garden features can be manipulated in order to promote beneficial arthropods in gardens. (1) Urbanization threatens biodiversity, yet urban native plants support native biodiversity, contributing to conservation and ecosystem services. Within urban agroecosystems, where non-native plants are abundant, native plants may boost the abundance and richness of beneficial arthropods. Nevertheless, current information focuses on pollinators, with little attention being paid to other beneficials, like natural enemies. (2) We examined how the species richness of native plants, garden management, and landscape composition influence the abundance and species richness of all, native, and non-native bees, ladybeetles, ants, and ground-foraging spiders in urban agroecosystems (i.e., urban community gardens) in California. (3) We found that native plants (~10% of species, but only ~2.5% of plant cover) had little influence on arthropods, with negative effects only on non-native spider richness, likely due to the low plant cover provided by native plants. Garden size boosted native and non-native bee abundance and richness and non-native spider richness; floral abundance boosted non-native spider abundance and native and non-native spider richness; and mulch cover and tree and shrub abundance boosted non-native spider richness. Natural habitat cover promoted non-native bee and native ant abundance, but fewer native ladybeetle species were observed. (4) While native plant richness may not strongly influence the abundance and richness of beneficial arthropods, other garden management features could be manipulated to promote the conservation of native organisms or ecosystem services provided by native and non-native organisms within urban agroecosystems. [ABSTRACT FROM AUTHOR]

Promoting wildlife habitat on working agricultural land is a growing conservation priority, and agri‐environment schemes are using payments for environmental services (PES) to reach these privately owned lands. PES can be ecologically effective, but also expensive, putting pressure on these schemes to be cost‐effective, maximizing the conservation value of their limited resources. This study assesses the cost‐effectiveness of four PES schemes in California that paid rice growers to provide temporary flood habitat on their working lands in support of shorebirds. It examines whether the schemes (1) paid for flood habitat only when needed (targeting); (2) paid for habitat that was actually delivered and would not otherwise be provided (additionality); (3) sacrificed as little habitat as possible when the habitat competed with production (ag/wildlife balance); and (4) fostered a commitment among growers to maintain the habitat after payments ended (permanence). Results show that the schemes fell short in each of the four goals, and they expose several factors that undermined their cost‐effectiveness. First, variable weather patterns altered the date in which the shorebird‐habitat gap emerged year‐to‐year, creating a dynamic and unpredictable target for the schemes to address. Second, growers' views on the compatibility of the flood habitat with their rice production varied widely and changed rapidly as the agricultural calendar progressed, making it a challenge to mitigate potential ag/wildlife conflicts. Third, water for flood habitat is expensive, and growers proved unwilling to shoulder that expense once payments ended. These results highlight the need for schemes to adopt design elements that can add flexibility, such as cancelation clauses, so that they can adjust to dynamic targets and adapt to changing ag/wildlife relationships. Results also suggest that PES schemes operating on working lands may require long‐term external support. That finding amplifies the imperative that schemes use their conservation resources cost‐effectively. [ABSTRACT FROM AUTHOR]

Context: Habitat connectivity is key when designing reserve networks for conservation of species at risk. Acquiring land over time to achieve connectivity for multiple species in a systematic conservation plan can pose a challenge because not all high priority parcels will be acquired, species occurrence data is often limited, and using multiple species models together is complex. Objectives: We evaluated four possible land acquisition strategies in a such a plan in their ability to meet each of three objectives. The strategies represent different combinations of what are termed 'Priority 1', 'Priority 2', and 'Corridor' lands in the plan. The objectives are to (1) meet conservation target acreages identified in the plan; these are distinct from connectivity goals, (2) maximize structural habitat connectivity, and (3) maximize connectivity for multiple focal species. Methods: For this case study in Yolo County, California, we compared the efficiency of strategies to meet conservation targets using MARXAN. We compared structural connectivity of MARXAN solutions for each strategy using FRAGSTATS and distance between patches using ArcGIS. We compared focal species connectivity by using ArcGIS to define species-specific least cost networks and then assessing each network's conformity with MARXAN solutions. Results: 'Priority 1' parcels and 'Corridor' parcels together provide (1) the most efficient solution for attaining conservation targets, (2) the highest structural connectivity, and (3) high connectivity for the greatest number of focal species. Conclusions: Because land acquisition patterns are time sensitive and data may be limited, we recommend using spatial prioritization software often and employing several measures of connectivity in decision-making. [ABSTRACT FROM AUTHOR]

The millipede fauna inhabiting deep soil are poorly known. They are small and threadlike, slow moving, lacking pigmentation, and rarely encountered due to their obscure underground way of life. One family, the Siphonorhinidae, encompasses four genera and 12 species in a fragmentary distribution in California, southern Africa, Madagascar, the Malay Archipelago, and Indo-Burma. The family is represented in the Western Hemisphere by a single genus, Illacme Cook & Loomis, 1928 from California, with its closest known relative, Nematozonium filum Verhoeff, 1939, from southern Africa. A new species of this family is documented from soil microhabitats in the Los Angeles metropolitan area, Illacme socal Marek & Shear, sp. nov. Based on this discovery and the recent documentation of other endogean millipede species, we show that these grossly understudied subterranean fauna represent the next frontier of discovery. However, they are threatened by encroaching human settlement and habitat loss, and conservation of this species and other subterranean fauna is of high importance. [ABSTRACT FROM AUTHOR]

Juvenile white sharks (JWS) of the Northeastern Pacific population are present in nearshore southern California waters and form mixed size class (~1.5–3 m) aggregations for weeks to months, often within 500 m of shore. These nearshore beach habitats are heavily used for human recreation (e.g., surfing, swimming, body boarding, wading, and standup paddleboarding) and the amount of spatio-temporal overlap between JWS and humans is currently unknown. Increases in human population and the Northeastern Pacific population of white sharks have raised concern over human beach safety. To determine spatio-temporal JWS-human overlap at various spatial scales (e.g., across the entire southern California coastline, across different distances from shore, and within specific beach locations), 26 beach locations across southern California were surveyed monthly resulting in 1644 aerial drone surveys between January 2019 to March 2021. Thirteen environmental variables were assessed to predict when spatio-temporal overlap between JWS and water users was highest. Coast-wide distribution of JWS was clumped, limiting human-shark co-occurrence to specific locations, with 1096 of 1204 JWS observations occurring at Carpinteria and Del Mar Beach locations. Nearshore distribution indicated JWS are often close enough to the wave break to interact with some water users (median = 101 m, range = 2–702 m), although JWS had the most spatial overlap with stand-up paddlers. Daily human-shark co-occurrence was 97% at beaches where JWS aggregations had formed, and human activity showed high spatial overlap at shark aggregation sites. Although there is higher seasonal human-shark spatio-temporal overlap where aggregations form in southern California, the number of unprovoked shark bites across southern California is extremely low. This study provides evidence that high human-shark spatio-temporal overlap does not lead to an increased bite frequency in southern California, and there are a number of possible explanations as to why JWS are not biting water users despite daily encounters. [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]

Rigorous understanding of how environmental conditions impact population dynamics is essential for species conservation, especially in mixed‐use landscapes where source–sink dynamics may be at play. Conservation of large carnivore populations in fragmented, human‐dominated landscapes is critical for their long‐term persistence. However, living in human‐dominated landscapes comes with myriad costs, including direct anthropogenic mortality and sublethal energetic costs. How these costs impact individual fitness and population dynamics are not fully understood, partly due to the difficulty in collecting long‐term demographic data for these species. Here, we analyzed an 11‐year dataset on puma (Puma concolor) space use, mortality, and reproduction in the Santa Cruz Mountains, California, USA, to quantify how living in a fragmented landscape impacts individual survival and population dynamics. Long‐term exposure to housing density drove mortality risk for female pumas, resulting in an 18‐percentage‐point reduction in annual survival for females in exurban versus remote areas. While the overall population growth rate appeared stable, reduced female survival in more developed areas resulted in source–sink dynamics across the study area, with 42.1% of the Santa Cruz Mountains exhibiting estimated population growth rates <1. Since habitat selection is often used as a proxy for habitat quality, we also assessed whether puma habitat selection predicted source and sink areas. Patterns of daytime puma habitat selection predicted source areas, while time‐of‐day‐independent habitat selection performed less well as a proxy. These results illuminate the individual‐ and population‐level consequences of habitat fragmentation for large carnivores, illustrating that habitat fragmentation can produce source–sink dynamics that may not be apparent from other metrics of habitat quality. Locally, conserving high‐quality source habitat within the Santa Cruz Mountains is necessary to support long‐term puma population persistence. More broadly, source–sink dynamics may at play for other carnivore populations in similar fragmented systems, and linking landscape conditions to population dynamics is essential for effective conservation. Caution should be used in inferring habitat quality from habitat selection alone, but these results shed light on metrics of selection that may be better or worse proxies to identify source areas for large carnivores. [ABSTRACT FROM AUTHOR]

Historically, wildfire and tribal burning practices played important roles in shaping ecosystems throughout the Klamath Siskiyou Bioregion of northern California and southern Oregon. Over the past several decades, there has been increased interest in the application of fire for forest management through the implementation of prescribed fires within habitats that are used by a diversity of migrant and resident land birds. While many bird species may benefit from habitat enhancements associated with wildfires, cultural burning, and prescribed fire, individuals may face direct or indirect harm. In this study, we analyzed the timing of breeding and molting in 11 species of culturally significant land birds across five ecologically distinct regions of northern California and southern Oregon to explore the potential timeframes that these bird species may be vulnerable to wildland fires (wildfire, prescribed fire, or cultural burning). We estimated that these selected species adhered to a breeding season from April 21 to August 23 and a molting season from June 30 to October 7 based on bird capture data collected between 1992 and 2014. Within these date ranges, we found that breeding and molting seasons of resident and migratory bird species varied temporally and spatially throughout our study region. Given this variability, spring fires that occur prior to April 21 and fall fires that occur after October 7 may reduce the potential for direct and indirect negative impacts on these culturally significant birds across the region. This timing corresponds with some Indigenous ecocultural burning practices that are aligned with traditionally observed environmental cues relating to patterns of biological phenology, weather, and astronomy. We detail the timing of breeding and molting seasons more specific to regions and species, and estimate 75%, 50%, and 25% quartiles for each season to allow for greater flexibility in planning the timing of prescribed fires and cultural burning, or regarding the potential implications of wildfires. The results of our study may serve as an additional resource for tribal members and cultural practitioners (when examined within the context of Indigenous Traditional Ecological Knowledge) and forest and wildland fire managers to promote stable populations of culturally significant bird species within fire‐dependent forest systems. [ABSTRACT FROM AUTHOR]

Positive associations between animals and foundational shrub species are frequent in desert ecosystems for shelter, resources, refuge, and other key ecological processes. Herein, we tested the impact of the density of the shrub species Ephedra californica on the presence and habitat use of the federally endangered lizard species, Gambelia sila. To do this, we used a 3‐year radio telemetry dataset and satellite‐based counts of shrub density across sites at the Carrizo Plain National Monument in San Luis Obispo County, CA. The effect of shrub density on lizard presence was contrasted with previous shrub cover analyses to determine whether measures of shrub density were superior to shrub cover in predicting lizard presence. Increasing shrub density increased lizard presence. As shrub density increased, lizards were located more frequently "above ground" versus "below ground" in burrows. Male lizards had significantly larger home ranges than females, but both sexes were similarly associated with increasing shrub densities. Shrub density and shrub cover models did not significantly differ in their prediction of lizard presence. These findings suggest that both habitat measures are effective analogs and that ecologically, both cover and the density of foundation shrub species are key factors for some desert lizards. [ABSTRACT FROM AUTHOR]

Laboratory‐based studies examining fish physiological and behavioural responses to temperature can provide important insight into species‐specific habitat preferences and utilisation, and are especially useful in examining vulnerable life stages that are difficult to study in the wild. This study couples shuttle box behavioural experiments with respirometry trials to determine the temperature preferences and metabolic thermal sensitivity of juvenile California horn shark (Heterodontus francisci) and leopard shark (Triakis semifasciata). As juveniles, these two species often occupy similar estuarine habitats but display contrasting behaviours and activity levels – H. francisci are relatively sedentary, whereas T. semifasciata are more active and mobile. This study shows that juvenile H. francisci and T. semifasciata have comparable thermal preferences and occupy similar temperature ranges, but H. francisci metabolism is more sensitive to acute changes in temperature as expressed through a higher Q10 (H. francisci = 2.58; T. semifasciata = 1.97; temperature range: 12–24°C). Underlying chronic temperature acclimation to both warm (21°C) and cool (15°C) representative seasonal temperatures did not appear to significantly affect these parameters. These results are discussed in the context of field studies examining known distributions, habitat and movement patterns of H. francisci and T. semifasciata to better understand the role of temperature in species‐specific behaviour. Juvenile H. francisci likely target thermally stable environments, such as estuaries that are close to their preferred temperature, whereas juvenile T. semifasciata metabolism and behaviour appear less dependent on temperature. [ABSTRACT FROM AUTHOR]

Habitat creation is a common element of efforts to recover populations threatened by altered habitat. Unfortunately, human‐created habitats do not necessarily support re‐establishment of target species. We investigated the value of constructed vernal pools as breeding habitat for the endangered Sonoma County population of California tiger salamanders (Ambystoma californiense) by conducting 19 years of larval surveys in 118 pools that were natural (n = 40), constructed (n = 70), or natural with substantial human alterations (human‐altered, n = 8). California tiger salamander larval densities in human‐altered and natural pools declined over the study period, while larval densities in constructed pools showed non‐negative trends. Larval declines in natural pools may be attributed to long‐term degradation of the surrounding terrestrial habitat. Mean larval densities over the course of the study were equivalent between constructed and natural pools, when corrected for pool morphometry. In contrast, human‐altered pools had lower larval densities. To assure consistent California tiger salamander breeding, pools needed to be ≥30 cm deep and 240 m2 in area, with deeper (50–70 cm) and larger (1,600–1,800 m2) pools providing increased larval productivity. Over the study, there was no evidence of decrease in the rate of colonization of new pools. We conclude that constructed pools can be important tools in the recovery of imperiled pool‐breeding amphibians if proper design elements for the target species are considered. [ABSTRACT FROM AUTHOR]

Carnivores with large home ranges are especially vulnerable to habitat fragmentation. As coyotes (Canis latrans) are often found living in highly modified landscapes, it is unclear how urban and suburban development impact gene flow between their populations. This study evaluated gene flow among coyotes inhabiting California sage scrub fragments within the highly developed Pomona Valley, California. We genotyped microsatellites from scat samples collected from four study sites to examine population structure between coyotes separated by a major freeway, coyotes separated by suburban development, and finally, coyotes in contiguous, natural habitat sites over 15 months. Though coyotes from all four sites were genetically distinct, near-complete turnover of individuals in sites and examination of temporal genetic structure and relatedness within one site indicated the movement of family groups through natural fragments over time. Thus, we argue that solely examining spatial genetic structure may create the illusion of genetic barriers among coyote populations where they may not exist, and that incorporating temporal components of genetic variation is critical to understanding gene flow across space and time in highly mobile animals. Understanding how to better study and manage coyotes, an apex predator, is key to the conservation of the endangered California sage scrub ecosystem. [ABSTRACT FROM AUTHOR]

Context: When human-made barriers impact wildlife by limiting habitat connectivity, simulation can reveal movements lost to fragmentation, strategies to restore corridor function, and potential benefits of corridor restoration. Objectives: Guided by previous genetic research, we examined desert bighorn sheep movement near two highways that restrict gene flow and modelled their movement and habitat selection behavior. The ultimate goal was to simulate movement without highway barriers as a means to site crossing structures that mitigate fragmentation and to reveal their benefits for habitat reachability. Methods: We fit integrated step selection functions (iSSFs) to GPS data from 9 bighorn populations near highways in California. After comparing iSSF simulations to validation data, we simulated 8200 bighorn-years of movement—200 year-long tracks each for 41 individuals—on a landscape with and without highways. We derived utilization distributions (UD) from simulations to identify probable high-use locations along the highways, compare these locations to previously predicted genetic corridors and roadkill events, and estimate changes in habitat reachability and elevation without these barriers. Results: Simulation UDs correlated well with observed bighorn movements. Barrier-free simulations indicated preferred corridors across highway-blocked valleys, often at the same locations predicted by landscape genetics models (4 of 6 genetic-based corridors matched simulation-based corridors), and where bighorn roadkill events occurred (3 of 3 roadkill events occurred at simulation-predicted corridors). Relative to barrier-present simulations, barrier removal increased accessible habitat for 8 of 9 populations, with increases ranging from 7 to 138% per population. Barrier-free conditions allowed movement to higher elevations in two populations. Conclusion: Animal movement simulation can effectively assess fragmentation impacts and reveal mitigation options when other data sources are scarce. Our simulations confirm previously predicted corridors, provide detailed locations for targeted mitigation, and suggest certain corridors pose greater habitat-related benefits. [ABSTRACT FROM AUTHOR]

Mature forests provide important wildlife habitat and support critical ecosystem functions globally. Within the dry conifer forests of the western United States, past management and fire exclusion have contributed to forest conditions that are susceptible to increasingly severe wildfire and drought. We evaluated declines in conifer forest cover in the southern Sierra Nevada of California during a decade of record disturbance by using spatially comprehensive forest structure estimates, wildfire perimeter data, and the eDaRT forest disturbance tracking algorithm. Primarily due to the combination of wildfires, drought, and drought‐associated beetle epidemics, 30% of the region's conifer forest extent transitioned to nonforest vegetation during 2011–2020. In total, 50% of mature forest habitat and 85% of high density mature forests either transitioned to lower density forest or nonforest vegetation types. California spotted owl protected activity centers (PAC) experienced greater canopy cover decline (49% of 2011 cover) than non‐PAC areas (42% decline). Areas with high initial canopy cover and without tall trees were most vulnerable to canopy cover declines, likely explaining the disproportionate declines of mature forest habitat and within PACs. Drought and beetle attack caused greater cumulative declines than areas where drought and wildfire mortality overlapped, and both types of natural disturbance far outpaced declines attributable to mechanical activities. Drought mortality that disproportionately affects large conifers is particularly problematic to mature forest specialist species reliant on large trees. However, patches of degraded forests within wildfire perimeters were larger with greater core area than those outside burned areas, and remnant forest habitats were more fragmented within burned perimeters than those affected by drought and beetle mortality alone. The percentage of mature forest that survived and potentially benefited from lower severity wildfire increased over time as the total extent of mature forest declined. These areas provide some opportunity for improved resilience to future disturbances, but strategic management interventions are likely also necessary to mitigate worsening mega‐disturbances. Remaining dry mature forest habitat in California may be susceptible to complete loss in the coming decades without a rapid transition from a conservation paradigm that attempts to maintain static conditions to one that manages for sustainable disturbance dynamics. [ABSTRACT FROM AUTHOR]

We developed spatial Bayesian hierarchical models to assess potential climate change impacts on suitable habitat for five important tree species in the Pacific northwestern United States (California, Oregon, and Washington). Individual‐species models were fit with presence–absence data from forest inventory field plots and spatial relationships were specified through a conditional autoregressive model. This modeling approach allowed us to visualize uncertainty in response curves, map current and future prediction uncertainty, and provide interval estimates for change. Upward elevational or northward latitudinal shifts in climatically suitable habitat were projected for all species. Climate change impacts were the most damaging for noble fir (Abies procera), for which 79%–100% of the current range was projected to become climatically unsuitable by the 2080s. Although coastal Douglas‐fir (Pseudotsuga menziesii var. menziesii) has been projected by others to gain habitat in Canada, within our study area we projected a net loss of climatically suitable habitat (ca. 8000–31,400 km2) under three of four future climate scenarios. A net loss in habitat was also projected for Oregon white oak (Quercus garryana) under three of four scenarios, with 40%–60% of the current range becoming unsuitable. Although there was no net loss of habitat for forest land blue oak under any scenario, other factors like competition may inhibit blue oak (Quercus douglasii) and white oak from occupying areas projected to increase in climatic suitability. Additionally, between 13% and 32% of blue oak's current range was projected to become unsuitable; some of these areas aligned with dieback following the 2012–2015 California drought, which our data set predates. Unlike the other four species, we projected a 17%–25% increase in climatically suitable habitat for California black oak (Quercus kelloggii), although 1%–20% of the current range was still projected to become unsuitable. Our findings indicate that, although some species will face more pressure in tracking climatically suitable habitat than others, climate change will impact the location of suitable habitat for many species. [ABSTRACT FROM AUTHOR]

From 2000 to 2013, an inventory was conducted by introductory entomology classes from the College of Marin (COM) with the twin goals of describing this insect community and enhancing students' educational experiences. General collecting was the main method, supplemented by rearing of immature stages and by light, pitfall, and pan trapping. After specimens were processed and identified, literature review provided information on five key life history traits of the species: area of origin, range, habitat, feeding habit, and dietary specificity. Four-hundred ninety species or morphospecies were recorded from 12 orders and 133 families. Diptera was the order with the most species. For 449 species with information available, 45% were plant feeders, 21% were predators, and 17% were parasites. For 274 species with information on dietary breadth, 57% were generalists and 43% were specialists. One species and four distinctive populations of other species were endemic to the site. Thirty-nine species had distributions likely restricted to the sand dunes of the immediate Pacific Coastal slope. Groups of species shared with adjacent habitats were also important components of the community. Findings are compared with the information available from other sand dune faunas. The diversity and uniqueness of this community warrant continued conservation efforts, especially the removal of invasive plant species. Students received benefits beyond those expected from the standard introductory course. Recommendations are made for improvement of the description of this community and for the more efficient integration of inventory of local insect faunas into general entomology classes. [ABSTRACT FROM AUTHOR]

Although fire is a fundamental ecological process in western North American forests, climate warming and accumulating forest fuels due to fire suppression have led to wildfires that burn at high severity across larger fractions of their footprint than were historically typical. These trends have spiked upwards in recent years and are particularly pronounced in the Sierra Nevada–Southern Cascades ecoregion of California, USA, and neighboring states. We assessed annual area burned (AAB) and percentage of area burned at high and low‐to‐moderate severity for seven major forest types in this region from 1984 to 2020. We compared values for this period against estimates for the pre‐Euro‐American settlement (EAS) period prior to 1850 and against a previous study of trends from 1984 to 2009. Our results show that the total average AAB remained below pre‐EAS levels, but that gap is decreasing (i.e., ~14% of pre‐EAS for 1984–2009, but 39% for 2010–2020 [including ~150% in 2020]). Although the average AAB has remained low compared with pre‐EAS, both the average annual area burned at high severity (AAHS) and the percentage of wildfire area burned at high severity have increased rapidly. The percentage of area burned at high severity, which was already above pre‐EAS average for the 1984–2009 period, has continued to rise for five of seven forest types. Notably, between 2010 and 2020, the average AAHS exceeded the pre‐EAS average for the first time on record. By contrast, the percentage of area that burned at low‐to‐moderate severity decreased, particularly in the lower elevation oak and mixed conifer forest types. These findings underline how forests historically adapted to frequent low‐to‐moderate severity fire are being reshaped by novel proportions and extents of high‐severity burning. The shift toward a high‐severity‐dominated fire regime is associated with ecological disruptions, including changes in forest structure, species composition, carbon storage, wildlife habitat, ecosystem services, and resilience. Our results underscore the importance of finding a better balance between the current management focus on fire suppression and one that puts greater emphasis on proactive fuel reduction and increased forest resilience to climate change and ecological disturbance. [ABSTRACT FROM AUTHOR]

Residential yards are a form of urban land use that cover a considerable amount of area in cities worldwide and provide important habitat for wildlife, especially when landscaped with native plants. Nevertheless, most native‐plant landscaping and wildlife research in the northern temperate regions of the world has been conducted during the spring and summer breeding period, leaving a gap in our understanding of the importance of residential yards and native plants as habitats for animals during the nonbreeding period. To fill this gap, we quantified the ecological role of native‐landscaped yards to avifauna throughout Greater Los Angeles (LA), California, during the winter nonbreeding period, which is a time of year when the region hosts a high abundance and diversity of migratory and resident birds. We surveyed birds and habitat features from October to March of 2020 and 2021 at 22 pairs of native‐ and non‐native‐landscaped yards plus 10 additional native‐landscaped yards. We had three objectives for our study. First, we compared avifaunal communities, including feeding and nonfeeding behaviors, and habitat features between native and non‐native‐landscaped yards. Second, we quantified relationships between habitat features and bird richness, abundance, and feeding and nonfeeding behaviors—focusing on species affiliated with urban or natural terrestrial ecosystems of the region. Third, we documented feeding and nonfeeding behaviors by birds with native and non‐native plants. Native‐landscaped yards had a greater cover of native trees, shrubs, and herbaceous plants, and a higher cover of natural habitat elements, including leaf litter and bare‐ground cover. Bird richness and abundance—especially bird species affiliated with tree‐ and shrub‐dominated ecosystems—were greater in native than non‐native‐landscaped yards. Further, yards with a higher cover of native plants supported greater numbers of feeding birds, with individuals focusing their foraging behaviors on distinct native trees and shrubs, including Quercus spp. (oak), Heteromeles spp. (toyon), Arctostaphylos spp. (manzanita), and Salvia spp. (sage). Our results suggest that residential yards landscaped with native plants provide important habitat for birds during the nonbreeding period and are a viable approach for residents and cities if improving conditions for birds throughout the annual cycle is a goal. [ABSTRACT FROM AUTHOR]

Effective management decisions depend on knowledge of species distribution and habitat use. Maps generated from species distribution models are important in predicting previously unknown occurrences of protected species. However, if populations are seasonally dynamic or locally adapted, failing to consider population level differences could lead to erroneous determinations of occurrence probability and ineffective management. The study goal was to model the distribution of a species of special concern, Townsend's big‐eared bats (Corynorhinus townsendii), in California. We incorporate seasonal and spatial differences to estimate the distribution under current and future climate conditions. We built species distribution models using all records from statewide roost surveys and by subsetting data to seasonal colonies, representing different phenological stages, and to Environmental Protection Agency Level III Ecoregions to understand how environmental needs vary based on these factors. We projected species' distribution for 2061–2080 in response to low and high emissions scenarios and calculated the expected range shifts. The estimated distribution differed between the combined (full dataset) and phenologically explicit models, while ecoregion‐specific models were largely congruent with the combined model. Across the majority of models, precipitation was the most important variable predicting the presence of C. townsendii roosts. Under future climate scenarios, distribution of C. townsendii is expected to contract throughout the state, however suitable areas will expand within some ecoregions. Comparison of phenologically explicit models with combined models indicates the combined models better predict the extent of the known range of C. townsendii in California. However, life‐history‐explicit models aid in understanding of different environmental needs and distribution of their major phenological stages. Differences between ecoregion‐specific and statewide predictions of habitat contractions highlight the need to consider regional variation when forecasting species' responses to climate change. These models can aid in directing seasonally explicit surveys and predicting regions most vulnerable under future climate conditions. [ABSTRACT FROM AUTHOR]

The southwestern pond turtle (Actinemys pallida), a chelonian species declining in California, depends on aquatic habitats for its survival. This study examined the extent to which the southwestern pond turtle used livestock ponds in rangeland habitat in eastern Santa Clara County, California, and the importance of key habitat features as factors in the presence of turtles in livestock ponds. We found that 12 of the 16 ponds (75%) previously documented to have southwestern pond turtles within the last 15 yrs still supported individuals, while only 1 of 62 ponds (2%) not previously documented as occupied, had turtles, indicating that livestock ponds, especially those known to be occupied, provide important, long-term habitat for this species. [ABSTRACT FROM AUTHOR]

A recently published macrogenetic dataset of California's flora and fauna, CaliPopGen, comprehensively summarizes population genetic research published between 1985 and 2020. Integrating these genetic data into the requisite "best available science" upon which conservation professionals rely should facilitate the prioritization of populations based on genetic health. We evaluate the extent to which the CaliPopGen Dataset provides genetic diversity estimates that are 1) unbiased, 2) sufficient in quantity, 3) cover entire species' ranges, and 4) include potentially adaptive loci. We identified genetic diversity estimates for 4,462 spatially referenced populations of 432 species, confirming California's rich published history of population genetics research. Most recent studies used microsatellites markers, which have uniquely high levels of variation, and estimates of all genetic metrics varied significantly across marker types. Most studies used less than 10 loci for inferences, rendering parameter estimates potentially unreliable, and covered small spatial extents that include only a fraction of the studied species' California distribution (median 16.3%). In contrast, the ongoing California Conservation Genomics Project (CCGP) aims to cover the full geographical and environmental breadth of each species' occupied habitats, and uses a consistent approach based on whole-genome data. However, the CCGP will sequence only 12% of the number of individuals, and covers only about half the evolutionary diversity, of the CaliPopGen Database. There is clearly a place in the evaluation of the genetic health of California for both approaches going forward, especially if differences among studies can be minimized, and overlap emphasized. A complementary use of both datasets is warranted to inform optimal conservation decision-making. Finally, a synopsis of the available population genetic data for California, all other US states and 241 other countries, allows us to identify states and countries for which meaningful data summaries, such as CaliPopGen, could be collated and others, which have limited published data available and are prime targets for future, empirical work. [ABSTRACT FROM AUTHOR]

Purposely introduced in 1879, Pacific coast Striped Bass Morone saxatilis once supported a commercial fishery and currently supports a recreational fishery in the San Francisco Estuary Watershed, CA, USA; however, the population has been in decline for decades. Since little is known about sub-adult behavior on the Pacific coast, we used acoustic telemetry to investigate seasonal movement patterns and habitat use across three regions (bay, delta, and river) and the effects of temperature and salinity on habitat use over a 2-year period. Sub-adult movement and habitat use differed by year and age. In spring, age-I and age-II sub-adults moved within the delta (60%), river (20%), and bay (20%) regions, and by summer, some individuals moved to the bay (36%), while others remained in the delta (42%) and river (22%). Fall and winter showed equal movement between the bay and delta regions. During year 2, age-II and age-III fish inhabited the bay region across all seasons with the exception of spring when a few individuals migrated up river. Generally, sub-adults did not inhabit the river region in fall or winter. Sub-adults were not detected in water temperatures < 10 °C and occurred most often in 20–25 °C. Younger sub-adults inhabited limnetic habitat where older fish inhabited mesohaline and polyhaline habitats. Our findings suggest that sub-adult seasonal movement patterns and habitat use hotspots have important fishery management implications and can be useful to address concerns over how this non-native fish's predation impacts native and endangered fishes. [ABSTRACT FROM AUTHOR]

California's sage scrub habitats support a diversity of nectar and host plants for migrating and resident populations of painted lady butterflies (Vanessa cardui) throughout all seasons. North America experiences spring V. cardui migrations involving butterflies totaling in the millions in some years. These irruptive years are thought to be driven by winter weather patterns at breeding grounds near the US–Mexico border and due to their irregularity, it is difficult to study floral resource use along the migration route. Here we used the community science platform iNaturalist to quantify patterns in V. cardui nectar resource use in sage scrub over time and space during irruptive and nonirruptive years. We identified over 329 different nectaring plant species of varying functional types (72% native to California) visited by adult V. cardui, 195 of which had not been previously identified as known nectar plants for V. cardui. Vanessa cardui butterflies were observed in similar locations regardless of whether an irruptive migration occurred, indicating the presence of either sparse migrants or resident populations across California. Moreover, irruptive years were positively correlated with warmer and wetter local conditions at observation locations. Our results provide new insights into patterns of floral resource use by North American V. cardui by harnessing the power of community science data and while highlighting the factors associated with its North American migration. [ABSTRACT FROM AUTHOR]

Programs that incentivize private landowners to create habitats that offset losses due to conversion and climate change are increasingly being used to bolster sensitive wildlife populations. In the Central Valley of California, shorebird habitat incentive programs pay landowners to create additional habitat during the non‐breeding season by flooding their fields. However, it remains unclear how successful these programs have been in supporting baseline shorebird population needs or meeting established population goals, particularly in the face of changing environmental conditions. To address these questions, we used bioenergetics modeling to estimate shorebird food energy needs over four consecutive years that had the highest annual mean air temperatures ever recorded in California, and included years of extreme drought, as well as the second wettest winter on record. Our objectives were to (1) characterize annual variability in the timing and magnitude of shorebird food energy shortfalls, (2) estimate the contributions that incentive programs made to meeting these needs, and (3) develop recommendations for implementation of future habitat programs to advance shorebird conservation in the region. Overall, we found a high level of consistency in the timing and magnitude of habitat shortfalls, especially in fall, despite large differences in annual rainfall, a result that was unexpected, but that emphasizes how highly managed the hydrological system is in the Central Valley. We also found that the magnitude of both fall and spring energy shortfalls increased, relative to recent (2007–2014) estimates, perhaps due to aberrantly warm conditions. Incentive programs implemented to provide supplemental habitat were somewhat effective in reducing shortfalls for the assumed baseline population, but there were consistent unmet habitat needs when there were not enough shallow open water foraging areas available. Strategies to offset these remaining food energy deficits include scaling up habitat investments, adjusting the timing of habitat programs to better match the migration patterns of the birds, and adapting programs to new geographies. To the extent that there is variability in annual habitat need we recommend implementing a dynamic conservation approach. This involves scaling the amount of additional habitat created to match the shifting needs of the birds to maximize return on investment. [ABSTRACT FROM AUTHOR]

Estimates of burn severity and forest change following wildfire are used to determine changes in forest cover, fuels, carbon stocks, soils, wildlife habitat, and to evaluate fuel and fire management strategies and effectiveness. However, current remote-sensing models for assessing burn severity and forest change in the U.S. are generally based on data collected from California, USA, forests and may not be suitable in other forested ecoregions. To address this problem, we collected field data from 21 wildfires in the American Southwest and developed region-specific models for assessing post-wildfire burn severity and forest change from remotely sensed imagery. We created indices (delta normalized burn ratio (dNBR), relative delta normalized burn ratio (RdNBR), and the relative burn ratio (RBR)) from Landsat and Sentinel-2 satellite imagery using pre- and post-fire image pairs. Burn severity models built from southwest U.S. data had clear advantages compared to the current California-based models. Canopy cover and basal area change models built from southwest U.S. data performed better as continuous predictors but not as categorical predictors. [ABSTRACT FROM AUTHOR]

The California Current Marine Ecosystem is a highly productive system that exhibits strong natural variability and vulnerability to anthropogenic climate trends. Relating projections of ocean change to biological sensitivities requires detailed synthesis of experimental results. Here, we combine measured biological sensitivities with high‐resolution climate projections of key variables (temperature, oxygen, and pCO2) to identify the direction, magnitude, and spatial distribution of organism‐scale vulnerabilities to multiple axes of projected ocean change. Among 12 selected species of cultural and economic importance, we find that all are sensitive to projected changes in ocean conditions through responses that affect individual performance or population processes. Response indices were largest in the northern region and inner shelf. While performance traits generally increased with projected changes, fitness traits generally decreased, indicating that concurrent stresses can lead to fitness loss. For two species, combining sensitivities to temperature and oxygen changes through the Metabolic Index shows how aerobic habitat availability could be compressed under future conditions. Our results suggest substantial and specific ecological susceptibility in the next 80 years, including potential regional loss of canopy‐forming kelp, changes in nearshore food webs caused by declining rates of survival among red urchins, Dungeness crab, and razor clams, and loss of aerobic habitat for anchovy and pink shrimp. We also highlight fillable gaps in knowledge, including specific physiological responses to stressors, variation in responses across life stages, and responses to multistressor combinations. These findings strengthen the case for filling information gaps with experiments focused on fitness‐related responses and those that can be used to parameterize integrative physiological models, and suggest that the CCME is susceptible to substantial changes to ecosystem structure and function within this century. [ABSTRACT FROM AUTHOR]

Nuanced understanding of seasonal movements of partially migratory birds is paramount to species and habitat conservation. Using nascent statistical methods, we identified migratory strategies of birds outfitted with radio-frequency identification (RFID) tags detected at RFID feeders in two sites in California, USA. We quantified proportions of migrants and residents and the seasonal phenology for each movement strategy in Allen's and Anna's hummingbirds; we also validated our methodology by fitting our model to obligate migratory black-chinned hummingbirds. Allen's and Anna's hummingbirds exhibited characteristics of facultative migratory behaviour. We also quantified apparent annual survival for each migratory strategy and found that residents had significantly higher probabilities of apparent survival. Low survival estimates for migrants suggest that a high proportion of birds in the migrant group permanently emigrated from our study sites. Considered together, our analyses suggest that hummingbirds in both northern and southern California sites partake in diverse and highly plastic migratory behaviours. Our assessment elucidates the dynamics underlying idiosyncratic migratory behaviours of two species of hummingbirds, in addition to describing a framework for similar assessments of migratory behaviours using the multi-state open robust design with state uncertainty model and single-site dynamics. [ABSTRACT FROM AUTHOR]

Grazing lands supporting livestock production and nature conservation exemplify land sharing conservation. In California, livestock producers own or manage a large portion of land with the highest biodiversity ecosystems. Grazing reduces flammable biomass and can benefit habitat of numerous rare and endangered species. However, the role of grazing, livestock production, and rancher stewardship in conservation is often overlooked. Spatial analysis shows a significant contribution of grazing lands to conservation in the San Francisco Bay Area (SFBA) that is not recognized in regional planning analyses. Lands protected for conservation cover nearly 0.5 million ha, or 29% of the SFBA, and 43% of the protected land is grazing land. Over 65% of the region's land described as essential or important to conservation by the regional planning network is grazing land. A case study review is used to examine in greater depth the management dynamics of partialtitle acquisition of grazing land for conservation. Exacted conservation easements, a type of easement fulfilling mitigation requirements for land development, are growing in use in the SFBA and throughout California, and they are well funded by development interests to support conservation. Political ecology theory terms a redefinition of territory that can displace resource users and enable others to benefit from newly created economic values, reterritorialization and capital accumulation. A case study of exacted easements on SFBA ranches reveals how the resulting redefining of the land's purpose and the significance of its various ecosystem services provides funding for third parties for new services required to implement and uphold the easements, but not necessarily to support land sharing and the ranching livelihood that provides grazing needed for habitat management. Planning that considers the needs of the livestock operation would increase the probability of achieving desired conservation outcomes and the durability of appropriate habitat conditions. [ABSTRACT FROM AUTHOR]

Generalist species can exhibit individual specialization (IS), where individuals adopt specialized foraging behaviors not attributable to age, sex, or social dominance. While IS increases with the diversity of available foraging resources (ecological opportunity), the potential impact of human food subsidies on ecological opportunity is unknown. We quantified the isotopic niche width of Steller's Jays (Cyanocitta stelleri), a synanthropic predator and dietary generalist, across a gradient of human land‐use categories ranging from subsidized (park campgrounds) to unsubsidized (forest interior) habitats in a protected area in California. We asked (1) if isotopic niche width was better predicted by individual foraging behavior than sex, social dominance, or habitat category (indicating IS) and (2) if degree of IS exhibited by jays increased with the availability of human food subsidies. We characterized the isotopic niche space occupied by individual jays relative to the population using carbon (δ13C) and nitrogen (δ15N) isotope values. Using linear models, we found that jay diet variation was best explained by individual behavior and habitat use rather than by sex or social dominance. While the degree of IS increased with the availability of human foods, individual jays exhibited a variety of foraging behaviors in all habitats that were segregated by foraging stratum and use of human foods. Individual diet also determined the degree of specialization, as jays that specialized on human foods had the narrowest niche width regardless of habitat. Management efforts targeted at generalist wildlife exhibiting large degrees of IS should therefore account for the impact of food subsidies on foraging behavior. Approaches that involve aversive conditioning may fail where highly specialized individuals are unlikely to encounter treatments; therefore, we recommend simultaneous efforts to limit human food subsidies (e.g., information campaigns and improved containment of human food and food waste), and deployment across the largest possible extent of foraging microhabitats and substrates in order to ensure exposure of whole populations to emetic eggs. [ABSTRACT FROM AUTHOR]

Urban landscaping conversions can alter decomposition processes and soil respiration, making it difficult to forecast regional CO2 emissions. Here we explore rates of initial mass loss and net nitrogen (N) mineralization in natural and four common urban land covers (waterwise, waterwise with mulch, shrub, and lawn) from sites across seven colleges in southern California. We found that rates of decomposition and net N mineralization were faster for high-N leaf substrates, and natural habitats exhibited slower rates of decomposition and mineralization than managed urban landcovers, especially lawns and areas with added mulch. These results were consistent across college campuses, suggesting that our findings are robust and can predict decomposition rates across southern California. While mechanisms driving differences in decomposition rates among habitats in the cool-wet spring were difficult to identify, elevated decomposition in urban habitats highlights that conversion of natural areas to urban landscapes enhances greenhouse gas emissions. While perceived as sustainable, elevated decomposition rates in areas with added mulch mean that while these transformations may reduce water inputs, they increase soil carbon (C) flux. Mimicking natural landscapes by reducing water and nutrient (mulch) inputs and planting drought-tolerant native vegetation with recalcitrant litter can slow decomposition and reduce regional C emissions. [ABSTRACT FROM AUTHOR]