Ecosphere最新文献

Globally, mass mortality events are becoming more common across ecosystems and taxa. For fishes in northern temperate lakes, climate change is predicted to increase the frequency of summerkills and decrease the frequency of winterkills. We compiled reports of fish kills in Michigan inland lakes from 1936 to 2022 derived from historical records, management reports, and an online app for the public. Using this dataset of 525 reported fish kills in eight decades, we tested for changes in timing of fish kills. We found that fish kills in the early 20th century were most likely to be reported in early spring months, as lake ice thawed, while in the later 20th and early 21st centuries, more fish kills were reported through summer. Across our dataset, the median day of year fish kills were reported shifted later by more than 50 days. Shifts in the timing of these perturbations can alter population demography, and community resilience, and may have lasting and unprecedented impacts on lake ecosystems.

Pollination services across rural–urban gradients may vary as land cover and other environmental attributes differentially influence pollinators. Most studies examining crop pollination, however, have been conducted in rural environments, while research in urban areas has lagged behind despite growing interest in urban agriculture. In this study, we hypothesized that increased urbanization would alter pollinator community composition due to a reduction in natural areas within the surrounding landscape, potentially decreasing pollinator abundance. To evaluate this hypothesis, we conducted a three-year study using strawberries as a focal study crop. We characterized the abundance, diversity, and community composition of bees across 10 farms along a rural–urban gradient in Michigan, USA. Across sites and years, we found that urbanization, measured as impervious surface cover, had no consistent effect on overall bee abundance and diversity. However, urbanization differentially influenced certain taxa, namely, Halictini which was positively associated with more urban environments in year one and Ceratinini which was negatively associated with more urban environments in year three. Sweat bees and small carpenter bees were the most frequent strawberry flower visitors across sites and years, although honey bees were dominant at rural sites in year one. We observed 61 bee species visiting strawberry flowers, most commonly Lasioglossum, Ceratina, and Augochlorella species. Most bee species were generalist foragers that visited many flower species within each site. Variation in strawberry floral visitors across years appeared to be driven by shifts in flower phenology, especially in year one when flowering was delayed due to the practice of flower removal to increase yield. Our study demonstrates the importance of wild bees, especially native species, as pollinators in urban agriculture and illustrates how habitat context shapes bee communities.

Understanding the evolutionary responses of anadromous salmon and trout to climate change is critical for effective conservation planning. In this study, we conducted a comprehensive review of literature published from 2010 to 2020 to synthesize current knowledge on climate impacts to these fish populations. Specifically, we focused on 199 papers that explored evolutionary processes in response to changing environmental conditions. Our analysis revealed several key themes, including the interwoven influences of climate and human activities on genetic variation, phenotypic traits, and population dynamics. We found that geographic patterns in genetic diversity are closely linked to climatic gradients, highlighting the importance to conservation strategies of variation in existing adaptive capacity. Additionally, temporal trends in phenology, maturation age, and fecundity indicate ongoing evolutionary and plastic responses to climate change. Importantly, human activities were identified as significant drivers of maladaptation in anadromous salmon and trout populations. We emphasize the need for targeted monitoring of specific evolutionary processes to mitigate the loss of genetic diversity and enhance adaptive capacity. Our study underscores the importance of identifying and protecting areas of high genetic diversity and rare genes, particularly in regions projected to experience rapid climatic shifts. In conclusion, our findings identify strengths and gaps in the research investigating the role of evolutionary dynamics in the face of climate change. By capitalizing on new tools for sequencing, genomic analysis, and automated field data collection, we can establish baselines for tracking evolutionary responses to climate change. Better integration of evolutionary processes into projections of future climate impacts will lead to more effective strategies to ensure the long-term resilience of these iconic fish species and other wildlife.

Non-native grazers compete with native species across the globe. We present a novel approach to study the composition of the herbaceous understory across three study areas within the Great-Basin with different historic and contemporary grazing regimes. We surveyed the landscape using distance sampling for livestock and horse feces as an index of use. In addition, we surveyed the herbaceous understory of random sites as well as sites chosen by female Greater sage-grouse to nest and brood their chicks. We used a novel Bayesian hierarchical modeling framework to link vegetation metrics with the spatial–temporal distribution of horses and livestock while accounting for observation error. When livestock and feral horses were not present, we found that Greater sage-grouse use sites with higher percentages of perennial grasses and forbs to build their nests and brood their chicks compared with what was available to them. As livestock increased, we found evidence for decreases in the percentage of perennial grasses, forbs, cheatgrass (Bromus tectorum), and increases in the amount of bare ground. These effects were consistent at available sites and brood sites; however, we found less evidence for an impact of livestock at nest sites. As feral horses increased, we observed similar results at available sites, but at sites chosen by females to nest and brood their chicks, we observed increases in the amount of invasive cheatgrass as feral horses increased, which could reflect attempts by Greater sage-grouse to compensate for reductions in protective cover. We present a noninvasive approach to assess space use that can be applied to other species. More importantly, we document that grazing by non-native ungulates impacts components of the plant community important to Greater sage-grouse reproduction. We provide spatial–temporal maps of livestock and feral horse use to aid managers attempting to balance the needs of livestock producers, feral horses, Greater sage-grouse, and ecosystem function.

Host species heterogeneity can drive parasite dynamics through variation in host competency as well as host abundance. We explored how elk (Cervus canadensis) with apparent subclinical infestations of winter tick (Dermacentor albipictus) may be a cryptic reservoir and drive winter tick dynamics, impacting moose (Alces alces) populations. We found that winter tick infestation loads did not vary remarkably between both host species and winter ticks sourced from elk and moose produced similar numbers of larvae which activated within 5 days of each other. We also found similar larval densities in habitats predominately used by elk, moose, and both host species. Our analysis of 2793 informative single-nucleotide polymorphisms showed genetic differentiation among tick populations that were only ~75 km apart, but fewer differences among ticks from elk or moose in the same locality, suggesting sharing of winter ticks across host species. Despite the clinical signs of high winter tick infestations being most apparent on moose, elk may be critical drivers of winter tick population dynamics and indirectly compete with moose in areas where they outnumber moose populations, a common characteristic of ungulate communities in western North America. Management interventions aimed at addressing winter tick issues on moose may wish to consider the movement patterns and abundance of cryptic reservoirs like elk.

Bats provide important ecosystem services as natural predators of, for example, lepidopteran pests. Thus, it is crucial to identify ways to enhance bat populations in agricultural landscapes. It has been shown that high landscape heterogeneity can benefit bat communities in arable fields. However, to date, the relationship between bats and the surrounding landscape within a viticultural matrix has received little attention, despite moths being major pests in viticulture. Here, we investigated how bats respond to different landscape elements in three European regions: Rhineland-Palatinate (Germany), Burgenland (Austria), and Andalusia (Spain). We recorded bat activity using passive acoustic monitoring for four nights in 94 vineyards in total. Additionally, in Germany, we recorded bat activity along transects from hedgerows up to 120 m into the vineyards to describe the change in activity with hedgerow distance. We found that bat activity decreased with distance from the hedgerow, and the strength of the response was guild-specific. Bat species adapted to foraging in the open space decreased their activity by half at a distance of 120 m from the hedgerow into the center of the vineyard, while bats adapted to foraging along vegetation (edge-space bats) and those adapted to feeding within and close to vegetation (narrow-space bats) decreased their mean flight activity by more than 80% at the same distance. Moreover, the presence of hedgerows between vineyards was positively related to a higher bat activity and feeding rate in all three countries, although this effect varied by functional guild and country. For edge-space foraging bats, hedgerows had a positive impact in all three countries, while open-space bats only showed a significant response in Spain. Hedgerows had consistent positive effects on bat activity in vineyards across the three study regions. Our study suggests that hedgerows should be conserved and restored as key elements to support a higher bat activity. This would also benefit other important groups of animals such as bees and birds along with the ecosystem services they provide.

The National Ecological Observatory Network (NEON) provides over 180 distinct data products from 81 sites (47 terrestrial and 34 freshwater aquatic sites) within the United States and Puerto Rico. These data products include both field and remote sensing data collected using standardized protocols and sampling schema, with centralized quality assurance and quality control (QA/QC) provided by NEON staff. Such breadth of data creates opportunities for the research community to extend basic and applied research while also extending the impact and reach of NEON data through the creation of derived data products—higher level data products derived by the user community from NEON data. Derived data products are curated, documented, reproducibly-generated datasets created by applying various processing steps to one or more lower level data products—including interpolation, extrapolation, integration, statistical analysis, modeling, or transformations. Derived data products directly benefit the research community and increase the impact of NEON data by broadening the size and diversity of the user base, decreasing the time and effort needed for working with NEON data, providing primary research foci through the development via the derivation process, and helping users address multidisciplinary questions. Creating derived data products also promotes personal career advancement to those involved through publications, citations, and future grant proposals. However, the creation of derived data products is a nontrivial task. Here we provide an overview of the process of creating derived data products while outlining the advantages, challenges, and major considerations.

Understanding animal behavior at the population level can be challenging, especially in the presence of intraspecific variation in behavioral tactics. Individuals within a population often vary with respect to resource exploitation and use, which may be associated with individual states (e.g., male or female) or extrinsic variation (e.g., temporal variation in food). Explicitly accounting for interindividual variation can aid ecological insights, especially for species that exhibit high behavioral flexibility. Here, we evaluated how seasonal fluctuations in resources influenced individual-level habitat use and selection of Rocky Mountain red fox (Vulpes vulpes macroura) within Grand Teton National Park, Wyoming. Rocky Mountain red fox is a high-elevation subspecies of the common red fox (Vulpes vulpes), and native to North America. From 2016 to 2021, we captured and GPS-collared 18 individuals (11 males, 7 females) and evaluated spatiotemporal shifts in home range characteristics and habitat selection. We observed high individual variation in home range size, with generally larger home ranges in the winter months ($��\overline{x}�$ = 72.92 km² [minimum convex polygon—MCP], 83.65 km² [Kernel], 27.20 km² [Local Convex Hull]) than in the summer ($��\overline{x}�$ = 22.23 km² [MCP], 23.01 km² [Kernel], 11.11 km² [Local Convex Hull]). Similarly, we observed substantial individual variation in habitat selection across environmental gradients. Some foxes altered their selection for habitat types between summer and winter indicating behavioral plasticity with respect to seasonal resources. Distance to human features was the primary driver for habitat selection for both seasons across foxes, and on average, foxes had stronger selection for human features in the summer. These findings might indicate some foxes are concentrating on the temporal and spatial resource pulse of anthropogenic food, while others exhibited more natural tactics. Our work advanced the spatial ecology of Rocky Mountain red fox, identified variation in space use tactics associated with humans and natural resources among red foxes in a heavily recreated area, and demonstrated how human activity can influence the spatial behavior of a carnivore within a national park.

Salt marshes are dynamic systems whose landscape structure and resilience to disturbance depend on bio-geomorphological interactions. The ecological niches of salt marsh plants are asserted to be organized along an elevational gradient, determining the impact of abiotic factors such as soil aeration, flooding, and salinity, which generate the typical salt marsh zonation. In the foremost (pioneer) zone, vegetation must cope with nonoptimal environmental conditions due to strong impacts of hydrodynamic forces and sedimentation and is threatened by climate change–induced sea level rise or increased storminess. To test the hypothesis that species have different elevational ranges, which are shaped by local abiotic conditions and biotic interactions, salt marsh species occurrences and covers were recorded along 65 seaward–landward transects at two study sites on the back-barrier island Spiekeroog in the German Wadden Sea, differing in topography, site age, and history. Elevations were extracted from a digital terrain model. Zero-inflated beta regression models demonstrated that species occurrence and cover are mediated by elevation in a species-specific manner. The fast colonizer Salicornia procumbens occurred foremost at the lowest elevations, followed by the pioneer species Spartina anglica and Salicornia europaea. The higher marsh species Limonium vulgare, Atriplex portulacoides, and Spergularia spp. occurred at higher elevations, indicating varying species' vulnerability to local abiotic factors. Furthermore, the individual cover of species was negatively related to the total cover of other species, possibly indicating that species-specific elevational ranges are further modified by interspecific interactions. Especially, the cover of the ecosystem engineer Sp. anglica mostly had negative effects on individual species cover, although positive effects on the cover of Sa. europaea at the eastern site. Our results provide insights into plant species responses and interactions under highly dynamic conditions in the foremost marsh zone. Knowledge about species-specific responses to their abiotic and biotic environment is an important prerequisite for modeling and predicting future ecosystem shifts in salt marshes under climate change.

Campus trees have significant potential for sequestering carbon in urban environments and improving civic life quality; however, few inventories of university campus trees have been constructed worldwide (excluding North America). This study briefly overviews the current status, challenges, and prospects of inventorying campus trees and provides a case study of a campus tree inventory and carbon assessment through a student participatory program in South Korea. Campus tree maps from 25 universities in eight countries were investigated. A campus tree inventory usually consists of various data on the tree species, dbh, and biomass, and it is often prepared through a capstone or student project in the university. This review identified the following challenges: (1) Few cases have been reported outside North America, (2) publications and data sharing are limited, and (3) participants' experiences have not been evaluated. The case study on inventorying and mapping campus trees was performed by integrating drone-based orthographic images and field censuses of tree data (species, diameter, GPS coordinates, etc.). A total of 2341 individual trees belonging to 73 species were surveyed over 28.7 ha of green spaces on campus, and various thematic maps were created online. In 2021, the aboveground carbon storage was 263.9 Mg C, and it increased annually by 5.62 Mg C. This study presents the first attempt to evaluate and report a campus tree carbon inventory at an East Asian university. Additional advancements in monitoring techniques and practices for campus trees may contribute to the sustainability of university campuses and local communities.