Ecological Applications最新文献

Despite the ecological expression and conservation importance of diverse behavioral tactics in animals, there is often friction associated with conventional analytical approaches and inference concerning variation in spatial behavior. Implicitly or explicitly, population-level inferences are generally the main objective of studies, but interpretations can be ambiguous in the presence of divergent behavioral tactics across individuals or cohorts, as with generalist species. We pursued a novel analytical approach and assessed the underlying mechanisms driving variation in spatial behaviors of generalist species using the American black bear (Ursus americanus) as our focal species. We quantified individual variation in habitat selection expressed by black bears using individual models for 35 collared bears across four study areas in Wyoming, USA. We modeled how state-dependent factors (age, sex, δ¹⁵Nitrogen, and body fat) and resource availability influenced behavioral variation in resource selection. We observed vast variation among individuals, demonstrating patterns consistent with a generalist species. Black bear resource selection differed with changes in state dependence and resource availability. Specifically, traits uniquely important to black bear success, body fat and carnivory, explained variation in selection for forage indexed by normalized difference vegetation index (NDVI), forests, and riparian areas. Environmental heterogeneity via differences in resource availability magnified behavioral variation in resource selection by black bears. Selection trends for NDVI and deciduous shrubs were explained by resource availability, indicating black bears exhibited functional responses in habitat selection. These insights emerged from our analytical approach; had we implemented a more conventional, population-level assessment, we would have simply concluded that black bears displayed behavioral neutrality with respect to forage resources. Acknowledgment of behavioral variation when considering spatial behavior of generalist species provides a more representative understanding of individuals within a population, and our analytical approach offers a solution to uncovering drivers of individual variation in spatial behavior.

Biodiversity is highly affected by ecological processes at the landscape level. To facilitate management decisions at a landscape level, we present an end-user-oriented framework that assesses the biodiversity capacity of individual biotopes in a fragmented landscape and ranks the importance of the biotope patches. The framework can be applied to any biotope and landscape. Analyses can further be done on planned or predicted future scenarios and changes in the landscape structure. There has been continuous exchange with stakeholders and case study testing with the purpose to build a tool that answers the important questions of end users, and provides results that are useful for decision-makers and environmental managers in environmental management and land use planning. The framework is novel in its calculations of the combined effects of connectivity and survival of biodiversity in the biotope patches. It uses land cover data and the concept of umbrella focal species as input. The framework strongly builds on ecological theory and ecological modeling, and produces three outputs of interest: a heatmap visualizing individual patch importance for upholding landscape biodiversity, an indicator metric of the ability of a biotope landscape to support biodiversity, and the number of unsustainable individual patches. The theoretical foundation and structure of the framework are thoroughly explained. The use of its output is further demonstrated by one selected case study where the calculations are applied to a biotope of fragmented old coniferous forest in Sweden. We additionally examine and show how the overall biodiversity potential of the biotope landscape is dependent on which types of species communities are in focus by applying different umbrella focal species. The case study demonstrates the importance of landscape structure for sustainable biodiversity. Results further demonstrate that it is essential to consider the type of species community that is the primary biodiversity conservation target.

The loss of plant diversity in grasslands is implicated as one of the main causes of arthropod decline. The loss of a single plant species can have a cascading effect on specialized arthropod species. It is thus critical to expand our understanding of plant–arthropod interactions. Detecting plant–arthropod interactions, however, has been difficult, as it requires the observation of individual plant visits. A possible solution to this problem is offered by environmental DNA (eDNA) analysis. Here, we test the utility of eDNA to detect fine-scaled community differentiation in grassland arthropods in Germany. Based on eDNA from 13 plant species, we explore community differentiation between plant species, and between flower and green parts of individual plants. We show that eDNA successfully recovers extremely fine-scaled community differentiation. Plant species, as well as plant compartment, emerge as major drivers of arthropod community composition in grasslands, with the differentiation being particularly pronounced in herbivorous arthropods. Terrestrial eDNA on plants thus appears to be deposited in a very localized fashion, making this tool ideally suited to detect very fine-scaled community differentiation. Considering the high specificity we observe in our analysis, our results highlight the necessity of integrating vegetation surveys into future monitoring of arthropod communities.

Ecological impacts of invasive species are mounting as their numbers and geographic extent continue to increase. Across extensive parts of their range, Pacific salmon (Oncorhynchus spp.) smolts face an expanding gauntlet of nonnative predators during their seaward migration. Adopting multispecies, spatiotemporal perspectives is essential for understanding direct and indirect predation risks and prioritizing management actions seeking to reduce impacts. Using quantitative DNA metabarcoding, we investigated trophic interactions of commonly co-occurring nonnative and native fish predators of Pacific Northwest, USA, salmon-bearing rivers, addressing challenges for salmon recovery and questions related to single-species management. Chinook salmon (Oncorhynchus tshawytscha) were frequently consumed by nonnative smallmouth bass (Micropterus dolomieu), largemouth bass (Micropterus salmoides), rock bass (Ambloplites rupestris), and native northern pikeminnow (Ptychocheilus oregonensis). Among the focal predators, Chinook salmon were the largest contributors to smallmouth bass diets, ranking as their second most important prey. Chinook salmon consumption peaked during a year of relatively high smolt abundance, low discharge, and warm stream temperatures. The following year, under opposite conditions, Chinook salmon consumption declined, though predation remained disproportionately high in certain mainstem and tributary regions. Native species of conservation concern were frequently consumed by nonnative predators, including imperiled native lamprey (family Petromyzontidae). Across space and time, native prickly sculpin (Cottus asper) and largescale sucker (Catostomus macrocheilus) were generally the highest contributing prey for nonnative predators. Intraguild predation was prevalent, most notably with smallmouth bass as the top prey for northern pikeminnow. Intraguild predation highlights potential risks of compensatory effects when predators are managed in isolation. Our study provides crucial insights into restoring food webs for native species while minimizing the likelihood of compensatory effects and demonstrates the value of quantitative DNA metabarcoding for understanding novel predator assemblages. As ecosystems worldwide face increasing pressures from co-occurring invasive species, integrating multispecies approaches into management strategies is essential for mitigating impacts and conserving biodiversity.

In theory, increasing sensitivity of primary productivity to precipitation variability is a biophysical symptom of dryland degradation, or “desertification,” but empirical tests of this in the context of biological invasions are scant. To test the potential for exotic grass invasion to exacerbate biophysical symptoms of desertification, we measured the biomass and biodiversity of herbaceous plant assemblages along a 41–248 mm/year precipitation gradient across the Mojave and San Joaquin Deserts within communities at high versus low levels of exotic grass invasion and under shrub canopies versus interstitial space, over 5 years. Exotic grass invasion doubled the conversion rate of precipitation into biomass, and native shrubs increased ecosystem sensitivity to precipitation through strong facilitation of exotic grasses. Invasion-driven increases in biomass production corresponded to significant decreases in native biodiversity. We propose that shrub facilitation of exotic grasses accelerated desertification by promoting a non-native flora that is highly sensitive to precipitation variability and strongly linked to biodiversity degradation. Suppressing exotic grasses and managing facilitated invasion will help mitigate desertification.

Peatland restoration aims to restore hydrology and peat-forming vegetation, supporting other ecosystem functions. However, the time required for complete vegetation recovery is generally unknown. Here, we investigate this in an experimentally restored, formerly afforested blanket bog in northern Scotland, which was plowed, fertilized, and planted with non-native conifers in the mid-1980s. Plowing created three “microforms”: Ridges, Original surface, and Furrows. Restoration management took place in two stages: trees were felled and drains blocked in 1998 (Standard treatment); then parts of the area were further rewetted with additional drain-blocking in 2015/2016 (Enhanced treatment). We recorded plant species composition in permanent quadrats 0, 5, 13, and 24 years after the start of restoration. Here we use an ordination-regression-based approach (ORBA) to predict time to plant species compositional recovery compared with a reference (comparable nearby intact blanket bog). For the first 13 years, plant species composition diverged from the reference, then later started to converge. If the current speed and direction of vegetation change were maintained, predicted time to recovery varies between 50–100 years and 120–285 years applying a relaxed or strict criterion for restoration success, respectively. Seven growing seasons after Enhanced treatment, recovery speed increased only for the driest microform, Ridge. Surprisingly, this microform was not predicted to take longer to recover than other microforms under either treatment. On the landscape scale, sloping areas were harder to restore than flatter areas, having longer predicted times to recovery. Complete vegetation restoration may take a long time because of legacies from the afforestation (e.g., increased nutrient availability) and the time taken to fully restore surface morphology and water table. On the other hand, other research has already demonstrated that the site is currently acting as a net carbon sink, despite the incomplete vegetation recovery. We argue that functions may be restored without full recovery of species composition. However, approaching the full suite of species may be desirable to support long-term resilience. Successful peatland restoration needs a strong science-practice partnership, where learning gained from monitoring both damaged and comparable intact peatlands can be used to adapt management interventions.

Marine protected area (MPA) networks are important for supporting biodiversity, enhancing ecosystem resilience, and facilitating species recovery. For the effectiveness of conservation and restoration, functional connectivity plays a vital role. The dispersal, movement, and successful establishment of organisms between suitable habitats and MPAs ensure long-term sustainability of the populations. Despite its importance, functional connectivity is rarely integrated into restoration planning, which limits the effectiveness of species reintroductions, habitat connectivity, and adaptation to environmental changes. In this study, we applied an integrative approach combining molecular detections (environmental DNA [eDNA] and meroplankton metabarcoding) with biophysical modeling to explore the functional connectivity between two Natura 2000 MPAs in the North Sea: Borkum Reef Ground (BRG) and Sylt Outer Reef (SOR). We focused on the European flat oyster (Ostrea edulis), a reef-building species that once provided vast reef habitats but is now functionally extinct in the German Bight and is therefore the subject of recent restoration measures at BRG. Our results showed partial but informative correspondence between molecular detections of oyster genetic traces and the modeled larval pathways during the June–July 2022 sampling period. We further explored larval dispersal across entire spawning seasons in 2022 and 2023. Connectivity between BRG and SOR was highly dependent on larval drift depth. Surface-drifting larvae showed strong interannual variability, with 3% reaching SOR in 2022 when northwesterly winds dominated, increasing to 22% in 2023 under westerly and southwesterly winds. Larvae drifting at depth, however, exhibited near-zero connectivity, leading to high self-recruitment rates, with over 25% settling near the original restoration sites. Our results demonstrate that wind-driven currents are a key driver of interannual variability in larval retention and dispersal. Additionally, they highlight the role of biological traits, such as vertical positioning and pelagic larval duration, in shaping connectivity between MPAs and oyster restoration sites. These findings emphasize the need to integrate connectivity assessments into MPA management and the restoration planning of reef-building benthic species. The interdisciplinary approach presented here provides a quantitative framework for assessing connectivity under species- and site-specific conditions, offering a transferable tool to evaluate the restoration potential of other species and enhance the functional network between MPAs.

Climate warming is expected to impact global biodiversity, especially in the rapidly warming Arctic. There is an urgent need to evaluate the demographic effects of climate warming under different greenhouse gas emission pathways to guide wildlife management and inform listing decisions under protected species legislation. We used forecasted environmental variables to drive a novel demographic model for the ringed seal (Pusa hispida), a circumpolar Arctic marine mammal and critical subsistence resource for Indigenous people. Under the most demographically plausible conditions and assumptions, the projected abundance of ringed seals in the Chukchi Sea west of Alaska, USA, changed by an average of −7% (range −25% to 4%) by 2058 and −71% (range −96% to −8%) by 2100. The choice of greenhouse gas emissions pathway was the most important determinant of population outcomes through its influence on two habitat variables, snow-on-ice depth and sea-ice area. The choice of climate model, the intrinsic population growth rate, density dependence, and polar bear predation had a moderate influence on population projections, while harvest by Alaska Natives had a small influence. Modeling results suggest that ringed seals in the Chukchi Sea can exhibit stable or increasing recruitment at average April snow-on-ice depths below 20–30 cm. Given that declining snow depth was central to listing the species as threatened under the U.S. Endangered Species Act, our work both represents the first quantitative investigation of future abundance for Alaskan ringed seals and is relevant to conservation assessments for the species.

Restoring lost and degraded ecosystems to enhance biodiversity and ecosystem services is a global priority, and animal responses to the restoration of habitats are a critical but undervalued component. Identifying the key drivers of animal colonization in restored habitats provides critical insights for restoration practitioners seeking to maximize ecological outcomes. When integrated into predictive frameworks and spatial decision-support tools, this knowledge becomes valuable for strategic planning, particularly in complex multihabitat restoration projects where spatial configuration remains a crucial yet understudied dimension influencing ecosystem recovery trajectories. We collect and analyze animal data from one of the world's largest multihabitat coastal restoration systems in Denmark, comprising restored seagrass (Zostera marina), boulder reefs, and mussel reefs. Using fine-scale spatial patterns in population abundances, we develop spatially explicit predictions across the seascape for various seagrass restoration scenarios and produce a series of optimizations. We consequently demonstrate that it is practical to configure restoration to optimize biodiversity objectives, including those linked with fished species. Species-specific responses translated to variable outcomes across restoration scenarios and optimizations. While the optimal number and arrangement of restored patches varied depending on the target species or species group (e.g., fisheries species or seagrass specialists), one near-ubiquitous arrangement was patchy seagrass planting. This aligns with current practice in the region, maximizes restoration efficiency and highlights the importance of not homogenizing seascapes for biodiversity. Our approach provides a practical framework for incorporating animal monitoring data into restoration planning, helping practitioners design and optimize spatial planting configurations to achieve specific ecological objectives.

Farmland abandonment occurs commonly across European mountain regions, which causes triggering of habitat encroachment through shrub regeneration and natural afforestation. However, its impact on vertebrate scavenger communities and ecological processes, such as the removal of small carcasses remains poorly understood. Through an experimental paired-plot design (grazed vs. abandoned-rewilded habitats), we monitored 99 small carcasses over two seasons (summer and winter) in traditional livestock grazing systems in the Guadarrama Mountains (central Spain) exposed to farmland abandonment. We evaluated how the composition and structure of the scavenger community as well as scavenging dynamics of small carcasses responded to habitat encroachment and seasonal changes. Our findings indicate that habitat encroachment following farmland abandonment significantly altered the composition and structure of the scavenger community and the ecosystem service of carrion removal. Rewilded habitats supported less diverse scavenger communities, with fewer species and individuals, dominated by mammalian facultative scavengers. In grazed habitats, almost all carcasses were consumed within 5 days, while in rewilded areas carrion removal was 2.35 times slower, with longer detection, consumption, and removal times. Seasonal changes amplified these differences, with winter bringing more diverse, bird-rich scavenger communities, but also longer carrion removal times, especially in grazed habitats. Our findings emphasize the ecological importance of small carcasses, which attract a wide range of scavengers, primarily facultative, and play a vital role in the scavenging dynamics of ecosystems. Passive rewilding has been proposed as a management strategy of no human intervention to create self-sustaining ecosystems that support biodiversity, enhance ecosystem services, and increase resilience to environmental change. However, our study shows that farmland abandonment alters small carrion-scavenging dynamics, reducing the effectiveness of carrion removal services and impairing bird scavengers, some of which are of conservation concern. These results highlight the need for land and wildlife managers, as well as policymakers, to consider these effects, particularly given the vast areas undergoing abandonment across Europe, and the potential implications for environmental legislation, such as the recent European Nature Restoration Law. This is crucial to ensure the maintenance of scavengers' diversity and the ecosystem service of carrion removal.