Abstract The diets of wild ungulates are a foundational component of their ecology, influencing their behavior, body condition, and demography. With changing environmental conditions, there is a significant need to identify important forage items for ungulates, but this has often proved challenging. Declines in several barren‐ground caribou herds across the North American Arctic have raised concerns about the influence of climate change on caribou forage conditions. Shifts in plant phenology, biomass, quality, and composition may be influencing caribou diets and subsequently affecting their body condition and demographic rates. Although forage is a primary driver of barren‐ground caribou behavior and population dynamics, there is limited recent information about the specific foods they consume, and uncertainty about appropriate methods for identifying those foods. Investigators are increasingly using fecal DNA metabarcoding and video camera collars to assess ungulate diets, but comparative studies of these approaches are lacking. To examine the summer diets of barren‐ground caribou, we used both fecal metabarcoding and video camera collars to identify forage used by the Porcupine caribou herd, which spans the Alaska–Yukon border. In 2021, we sampled the diets of adult females by collecting fecal samples and observing collar videos during 4 sampling occasions. We found that caribou consumed very specific forage items, and those items varied markedly across the growing season. Caribou predominantly consumed graminoids and lichens during early summer, and shrubs and forbs later in the season. Metabarcoding and video data provided significantly different estimates of diet for all taxonomic levels we evaluated, and inferences from the two approaches were often disparate. Metabarcoding failed to detect some items frequently consumed in videos, such as lichens, and indicated high use of other items rarely consumed, such as mosses. We found that video data provided greater taxonomic diversity and resolution for vascular plants and lichens, and more closely aligned with past research and biological expectations than data from fecal metabarcoding. Additional research is needed to be able to use these methods to identify the biomass of different forage items consumed.

Abstract Reintroduction of endangered species is wrought with many challenges, but one often overlooked challenge is the threat of predation of naïve individuals. Individuals lacking the insight to avoid predators can become easy prey and even showcase predators capitalizing on the lack of anti‐predator behavior. In California, California condors (Gymnogyps californianus) have slowly been recovering since the implementation of recovery actions and management. However, here we report an instance of where three California condors were preyed upon by a puma (Puma concolor) from 28 November to 30 December 2010 near Bitter Creek National Wildlife Refuge, Kern County, California, USA. The puma cached all three condor carcasses and was detected on a nearby camera trap revisiting the carcasses; scat was also identified nearby. This rare photographic documentation not only highlights the relatively unexplored ecological relationship between pumas and California condors but also showcases the need to understand the role predatory naïve behavior has on endangered species survivorship.

Abstract Species distributions depend on fine‐scale ecological processes and population growth trajectories and are influenced by climate and weather changes. However, the characterization of inter‐population dynamics underlying the geographic distributions of migratory organisms remains challenging. We adopted a stable isotope approach to investigate the dynamic population geography of a terrestrial migratory bird across multiple generations. We found that the age‐specific geographic source of Mountain Plovers sampled during winter shifted over four years across a latitudinal gradient. Moreover, our results show that differential effects of climate on the probability of occurrence at the wintering ground could be a driver of population turnover in a migratory species adapted to extreme environmental stochasticity (i.e., drought occurrence). We propose a framework for the identification of spatial and temporal climate and weather components and respective effects on population composition and recruitment into migratory wintering populations. Our approach is useful to reveal population compositional shifts through hydrogen stable isotope analysis while accounting for cumulative drought effects.

Abstract Variation in insect herbivory can drive variation in plant fitness and population dynamics. However, our ability to predict the ecological contexts in which insect herbivores will reduce plant fitness or population growth is limited. In theory, populations at the periphery of a plant species' biogeographic range are expected to experience reduced herbivory. Further, in montane landscapes, elevation is expected to drive variation in abiotic conditions and variation in plant–insect interactions. Specifically, less insect herbivory may occur at cooler, higher elevations. To examine these predictions, we quantified effects of inflorescence‐ and seed‐feeding insect herbivores in populations of the short‐lived, monocarpic, perennial forb Cirsium canescens (Platte thistle) in montane grasslands in Colorado, USA. We asked: (1) Does insect flower head herbivory and pre‐dispersal seed predation limit Platte thistle lifetime seed production? (2) Does this insect herbivory limit seedling recruitment? (3) Does ecological context, including spatial—especially elevational—and temporal variation, affect the outcome of these interactions? We conducted insect exclusion experiments in three years at five sites over 52% of Platte thistle's elevation range in our region. We compared both lifetime viable seed production and seedlings recruited between plants with ambient versus insecticide‐reduced levels of flower head herbivory. Insect herbivory on flower heads significantly reduced Platte thistle lifetime viable seed production at all sites, independent of elevation. Unexpectedly, however, increasing seed by reducing herbivory did not lead to a proportional increase in seedling recruitment. The relationship between viable seed production and seedling recruitment per plant was non‐linear, decelerating across the range of seed production achieved by both plants exposed to and protected from flower head herbivory. While elevation altered Platte thistle flowering phenology, it did not influence insect damage, viable seed production, or seedling recruitment. These results show that flower head‐ and seed‐feeding insect herbivores strongly reduced Platte thistle lifetime viable seed production, a key component of maternal fitness, in these peripheral populations. Yet, the herbivory did not determine population recruitment, suggesting post‐dispersal processes limit recruitment here. Further, elevation did not drive context‐dependent variation in the insect herbivore outcomes.

Abstract Knowledge on the spatial distribution of plant species richness and its associated factors is crucial for addressing several ecological problems. Climate factors have long been used to explain species richness patterns across space and time. In this study, we investigated how water and energy variables shape species richness patterns on the alpine Tibetan plateau. An empirical study involving 800 plots of size 1 m2 on 80 different sites was conducted across two transects, covering the arid and semi‐arid alpine region of the western part of the Tibetan plateau to explore plant species composition and richness in relation to climatic factors at a regional scale. We performed detrended correspondence analysis and generalized linear models to explore the effect of energy and water variables on species composition and species richness, respectively. We used a generalized linear mixed model to investigate the interactive effect of energy variables and water variables on species richness. We found that both energy variables and water variables significantly influenced species richness and composition on the alpine Tibetan plateau and supported the water–energy dynamics (WED) hypothesis. Specificall, plant species richness increased with greater liquid water availability. However, it exhibited a unimodal relationship with potential evapotranspiration. Our results also showed that precipitation played a more substantial role in the model than potential evapotranspiration, but their interaction strengthened the model. In conclusion, this study highlights the dominant role of precipitation in explaining species composition and richness patterns on the alpine Tibetan plateau and suggests conducting research on additional environmental factors affecting water availability in this region.

Abstract Tropical coral island vegetation poses formidable challenges, particularly in elucidating the determinants of vegetation species richness. In response, our study compared the differences in plant species biodiversity and soil physicochemical properties on seven adjacent coral islands at different stages of vegetation succession, from bare land to 100% vegetation coverage in the South China Sea, all of which were less than 0.3 km2. Contrary to the established island ecological theories, our results indicated that soil nutrients significantly govern the species diversity of tropical coral islands. However, the timing of soil development, island area, distance from larger islands, and island altitude were not significantly correlated. Cluster analysis showed that the diverse islands of Qilianyu Island (Seven Sisters) represent distinct stages of tropical coral island succession: pioneer vegetation, shrub and grass communities, and coral island forest vegetation. As island vegetation underwent succession, plant species increased from 6 to 57, and organic carbon, total nitrogen, and available phosphorus content significantly increased, accompanied by increasing salinity and decreasing pH. Our findings revealed a nested structure in the vegetation of tropical coral islands, primarily dominated by environmental filtering on a small scale, at least on Qilianyu Island. This indicates that the restoration of damaged island vegetation can begin with soil rehabilitation. We contend that improving soil nutrient conditions and development status contribute to the establishment of island vegetation, with careful consideration of interspecific combinations that expedite the restoration process on tropical coral islands. This study addresses the lack of clarity surrounding the determinants of vegetation species richness on tropical coral islands, thus providing a novel perspective grounded in soil nutrient‐driven succession.

Abstract Artificial light at night poses a global threat to biodiversity and is increasing at a rate greater than any other pollutant. We conducted a field experiment to investigate the effects of short‐term nighttime illumination on nocturnal flying insects and insectivorous bats in previously unlit remnant bushland. We compared these organisms' responses to three types of light‐emitting diode (LED) lights, each with a unique spectral composition (cool white [CW], λP 457 nm; filtered white [FW], λP 586 nm; and amber [A], λP 601 nm), as well as a control (C) group without illumination. Our findings revealed that both CW and FW LEDs significantly increased the total activity of flying insects, particularly the orders Diptera, Coleoptera, and Hymenoptera. By contrast, total bat activity was independent of light treatment, but there was a marginally non‐significant effect on bats presumed to be light sensitive. Amber lights appear to mitigate the disruptive effects of light on at least one light sensitive bat species. Intriguingly, despite a positive association in one bat species with insect abundance, there was no corresponding increase in feeding activity around illuminated sites in this or any other species. These observations suggest that bats may not solely exploit the attraction of insects to LED lights as a feeding resource and that those species that persist in these environments are perhaps more light tolerant than light exploitive. Overall, our study highlights potentially complex responses of Australian insectivorous bats and flying insects to short‐term LED lighting and contributes further insights into the ecological consequences of nighttime lighting.

Abstract Big sagebrush (Artemisia tridentata) is a widespread and locally dominant shrub throughout many ecosystems in western North America. A. tridentata ssps. tridentata and wyomingensis are two subspecies whose populations occupy the warm‐arid regions of the species range and whose trailing edge is threatened by climate change. Previous studies have presented conflicting results in relation to the genetic control of physiological variation in A. tridentata. Understanding how different genetic factors contribute to physiological variation can provide insight into how these two subspecies may respond to future climate change. To explore possible variation among and within two subspecies of A. tridentata, we measured physiological and morphological traits in A. t. tridentata and A. t. wyomingensis during mid‐summer (July), seven years after establishment in a common garden. Contributions to trait variation were quantified for both genetic (subspecies and cytotype) and environmental (climate‐of‐origin) factors. Measurements revealed an unequal contribution to phenotypic variation by subspecies, cytotype, and climate‐of‐origin. Ploidy and climate‐of‐origin were more important than subspecies in driving phenotypic variation in A. tridentata. These findings suggest that A. tridentata has a highly plastic drought response, or that culling (mortality over time due to environmental factors) in the common garden over seven years has led to a lack of genetic diversity within the garden. Understanding what factors drive phenotypic expression in big sagebrush can provide better insight into how climate change may affect migration and extirpation and may aid in the effectiveness of restoration efforts.