Subsidy-stress gradients offer a useful framework for understanding ecological responses to perturbation and may help inform ecological metrics in highly modified systems. Historic, region-wide shifts from bottomland hardwood forest to row crop agriculture can cause positively skewed impact gradients in alluvial plain ecoregions, resulting in tolerant organisms that typically exhibit a subsidy response (increased abundance in response to environmental stressors) shifting to a stress response (declining abundance at higher concentrations). As a result, observed biological tolerance in modified ecosystems may differ from less modified regions, creating significant challenges for detecting biological responses to restoration efforts. Using the agriculturally dominated Mississippi Alluvial Plain (MAP) ecoregion in Mississippi, USA, as a case study, we tested the hypothesis that macroinvertebrate taxa that typically display a subsidy response to nutrient enrichment in less modified ecoregions (i.e., nutrient-tolerance) shift to a stress response to increasing nutrients in highly modified watersheds with elevated baseline nutrient conditions (i.e., nutrient intolerance). The abundance and diversity of MAP-specific intolerant taxa identified with threshold indicator taxa analysis were either unresponsive or exhibited a subsidy response to increasing nutrients in less modified ecoregions in Mississippi with less land alteration and lower nutrient concentrations, but declined at higher concentrations, providing evidence for a stress response to elevated nutrients in the MAP. Additionally, MAP-specific tolerant and intolerant taxa richness responded to increased nutrients predictably and consistently across space and time within the MAP. However, in MAP streams, elevated specific conductance was predicted to dampen the response of tolerant and intolerant taxa richness to increasing nutrient concentrations, highlighting the importance of considering multistressor interactions when interpreting biological data. Lastly, we demonstrate the efficacy of this approach with sediment bacterial communities characterized with amplicon sequencing, which lack sufficient life history characteristics necessary for the development of multimetric indices. Both macroinvertebrate and bacterial communities responded similarly to increasing nutrient concentrations, suggesting DNA-based approaches may provide an efficient biological assessment tool for monitoring water quality improvements in highly modified watersheds.

Human-caused conversion of natural habitat areas to developed land cover represents a major driver of habitat loss and fragmentation, leading to reorganization of biological communities. Although protected areas and urban greenspaces can preserve natural systems in fragmented landscapes, their efficacy has been stymied by the complexity and scale-dependency underlying biological communities. While migratory bird communities are easy to-study and particularly responsive to anthropogenic habitat alterations, prior studies have documented substantial variation in habitat sensitivity across species and migratory groups. This may make approaches that explicitly consider the hierarchical nature of ecological organization useful for planning and decision-making, particularly in developed landscapes. Herein, we leverage regional vegetation and breeding bird monitoring efforts to investigate the influences of spatial scale, urbanization, and migratory habit on breeding bird occupancy across Cleveland Metroparks, a large urban park system in Ohio. Using multispecies occupancy models, we found that fine-scale vegetation covariates were more predictive of bird community dynamics than landscape-level covariates, suggesting positive benefits of vegetation management activities for breeding bird communities. We also found that short-distance migrants were positively associated with plants that have broad ecological tolerances and that tropical migrants were more negatively associated with human development than other migratory groups. While local vegetation management may be effective for protecting sensitive breeding bird communities, many tropical migrants required intact forests with low human development and may require targeted habitat management for continued breeding-season occupancy. More broadly, this study emphasizes how avian management strategies in developed landscapes should consider features at multiple spatial scales-as well as species-specific migratory behaviors.

Grassland restoration is an important conservation intervention supporting declining insect pollinators in threatened calcareous grassland landscapes. While the success of restoration is often quantified using simple measures of diversity or similarity to target communities, these measures do not capture all fundamental aspects of community reconstruction. Here, we develop species-habitat networks that aim to define habitat-level foraging dependencies of pollinators across restored grassland landscapes and compare their value to these more conventional measures of community restoration. We assessed this across Salisbury Plain (UK), which represents the largest area of chalk grassland in northwestern Europe, encompassing six distinct management types aimed at the restoration and maintenance of species-rich calcareous grassland. Sites that were previously disturbed or reverting from arable agriculture were comparable with those of ancient grasslands in terms of pollinator abundance and species richness. However, intensively managed grasslands exhibited notably lower values across nearly all measured indicators, including flower and pollinator richness and abundance, than ancient grasslands, with unmanaged grasslands following closely behind. This underscores the need for caution with both long-term neglect and highly intensive management. Applying our species-habitat network approach, we found that pollinator communities in grasslands recovering from past military disturbance showed stronger modular associations with those in ancient grasslands than areas recovering from intensive agriculture. This highlights the importance of habitat history in shaping restoration trajectories. We propose that species-habitat networks should be part of the standard analytical toolkit assessing the effectiveness of restoration at landscape scale, particularly for mobile species such as insects.

A central goal of ecosystem restoration is to promote diverse, native-dominated plant communities. However, restoration outcomes can be highly variable. One cause of this variation may be the decisions made during the seed mix design process, such as choosing the number of species to include (sown diversity) or the number of locations each species should be sourced from (source diversity, manipulated to affect genetic diversity). The effects that seed mixes have on plant communities may be further modified by other factors at the restoration site, including edge proximity and consumer pressure. Few studies have evaluated both these seed mix attributes together, and none have done so while accounting for realistic restoration site attributes. To address this research need, we conducted a prairie restoration experiment where two aspects of seed mix design (sown diversity and source diversity) and two restoration site factors (edge proximity and vertebrate granivore/herbivore consumer access) were manipulated across 12 replicate fields. We found that when seed mix design impacted plant community structure, these effects were dependent on consumer access or edge proximity and were more prominent after one versus five growing seasons. Low seed source diversity plots had more sown species than high source diversity ones, but only when consumers had access. Similarly, low species diversity plots had higher richness and cover of species included in both the low and high species diversity mixes, but this effect weakened over time. Additionally, plots with high species diversity were buffered from the typically detrimental effects of edges and consumers, although this did not always result in greater sown species abundance. Unexpectedly, plots with the most sown species were those sown with either low source diversity or low species diversity seed mixes, perhaps due to lower seeding rates of reliably establishing species. Our results illustrate how the influences of seed mix design on restored plant communities can be highly contingent on factors like edges, consumers, and time.

Although agriculture and plantation forestry have decreased natural open habitats and old-growth forests, conservation in managed lands is considered essential for achieving "nature-positive" goals that reverse biodiversity trends from negative to positive. From subboreal to temperate regions, mature conifer plantations with broadleaved trees (BLTs) offer suitable habitats for species preferring mature natural BLT forests, whereas young plantations harbor species depending on early successional (ES) habitats. However, the functional forms of stand age and BLT, and their context dependency, remain unknown. We quantified the effects of stand age (3-98 years), BLT proportion (0%-97.5%), and their interaction on ES and BLT bird species in plantations, as well as the dependency of these effects on regional/seasonal climates. For both groups, we also explored whether plantations could be comparable habitats to BLT-dominated natural forests (stand age: 6-134 years) across Hokkaido (78,420 km), northern Japan. ES bird species' richness and abundance decreased exponentially with stand age in plantations. This pattern was not evident in natural forests although only two ES stands were surveyed due to the rarity of natural forest harvesting. ES plantations in cooler regions showed higher habitat values, reflecting a climate-dependent species composition. No ES species occurred in winter. Both stand age and BLT proportion increased BLT bird species richness and abundance in a concave manner, except for age in stands with few BLTs. The positive effects of BLT were more evident in younger stands with fewer BLTs. Mature plantations with 25% BLTs supported 62% of breeding BLT bird abundance in old natural forests. In winter, lower regional temperatures weakened the positive effects of stand age and strengthened the positive effects of BLT proportion, reflecting temperature-dependent habitat selection across species. Our results suggest that regular plantation harvesting can play a critical role in restoring ES bird species across Hokkaido. To conserve BLT bird species, retaining even small amounts of BLTs within plantations may be more cost-effective than long-rotation plantation forestry or only protecting existing natural old-growth forests. Our study shows that on-site conservation within plantations across regions and seasons, when coupled with nature reserve management, can contribute to restoring biodiversity.

Fencing is one of the most widely utilized tools for reducing human-wildlife conflict in agricultural landscapes. However, the increasing global footprint of fencing exceeds millions of kilometers and has unintended consequences for wildlife, including habitat fragmentation, movement restriction, entanglement, and mortality. Here, we present a novel and quantitative approach to prioritize fence removal within historic migratory pathways of white-bearded wildebeest (Connochaetes taurinus) across Kenya's Greater Masai Mara Ecosystem. Our approach first assesses historic and contemporary landscape connectivity of wildebeest between seasonal ranges by incorporating two sets of GPS tracking data and fine-scale fencing data. We then predict connectivity gains from simulated fence removal and evaluate the impact of different corridor widths and locations on connectivity and removal costs derived from locally implemented interventions. Within the study system, we found that modest levels of fence removal resulted in substantial connectivity gains (39%-54% improvement in connectivity for 15-140 km of fence line removed). By identifying the most suitable corridor site, we show that strategically placed narrow corridors outperform larger, more expensive interventions. Our results demonstrate how and where targeted fence removal can enhance connectivity for wildlife. Our framework can aid in identifying suitable and cost-effective corridor restoration sites to guide decision-makers on the removal of fences and other linear barriers. Our approach is transferable to other landscapes where the removal or modification of fences or similar barriers is a feasible mitigation strategy to restore habitat and migratory connectivity.

Intercorrelated aboveground traits associated with costs and plant growth have been widely used to predict vegetation in response to environmental changes. However, whether underground traits exhibit consistent responses remains unclear, particularly in N-rich subtropical forests. Responses of foliar and root morphological and physiological traits of tree and herb species after 8-year N, P, and combined N and P treatments (50 kg N, P, N and P ha year) were examined in leguminous Acacia auriculiformis (AA) and nonleguminous Eucalyptus urophylla (EU) forests in southern China. N addition did not significantly impact all leaf and root traits except root N concentration per root length. Root traits responded to P addition more than leaf traits in trees; however, both traits responded similarly to P addition in herbs. Tree species deviated from the expected leaf economics spectrum; however, all species aligned with the root economics spectrum. The P and combined N and P treatments significantly altered the position of principal components analysis of root functional traits for herb species compared to the control. However, these changes did not reflect a classic shift in nutrient acquisition strategy within the root economics spectrum. As leguminous species experienced greater P limitation, AA responded more to P addition than EU; their understories indicated no significant differences. This study reveals how plant aboveground and underground traits adapt to nutrient-rich environments. These findings highlight the importance of incorporating plant underground traits, which show significant and specific responses to nutrient additions, into Earth system models for accurately predicting plant responses to global change.

Livestock grazing and trampling have been shown to reduce arthropod populations. Among arthropods, defoliating lepidopterans are particularly important for their impact on trees, the keystone structures of agroforestry systems. This study investigates the impact of livestock on the community of defoliating lepidopterans in agroforestry systems. We conducted both experimental and observational studies in the mid-west and western regions of the Iberian Peninsula. In our field experiment, we sampled lepidopteran caterpillars in areas with livestock and in areas where livestock had been excluded for short and long periods. To validate our experimental results, we conducted a field survey across seven areas with and without livestock in the western Iberian Peninsula. Our findings revealed that after 2 years from the start of the experiment, the exclusion of livestock led to an increase in the abundance and species richness of lepidopterans, as well as shifts in their community composition. Our experimental findings were corroborated by our field survey. Interestingly, we found that the differences in community composition among exclusions were primarily due to species nestedness. Livestock exclusion consistently favored species that pupate in the ground, suggesting that livestock can alter the lepidopteran community by predating or accidentally trampling these species. This study underscores the significant role livestock play in modifying the community of defoliating lepidopterans in Mediterranean agroforestry systems (oak savannahs), with important implications for food webs and species interactions.

Wild solitary bees face a host of challenges from the simplification of landscapes and biodiversity loss to invasive species and urbanization. Pollinator researchers and restoration workers thus far gave much attention to increase flower cover to reduce the impact of these anthropogenic pressures. Over 30% of bee species need nonfloral resources such as leaves and resin for their survival and reproduction. However, the importance of leaves in bee ecology, particularly for leafcutter bees, has received very little attention. Leafcutter bees have global distribution and cut leaves for constructing brood chambers. We have very little information for (a) what bees use and do not use for foraging leaves and (b) what leaf and plant traits and plant community traits drive plant preference and plant usage. To fill this gap and recommend plants for leafcutter bee conservation, we examined 13,062 plants of 612 species and 107 families distributed in 165 plant communities of nine towns/cities of four south Indian states. The plant community of nine locations and four states was quite dissimilar, but had similar proportion of native and exotic plants. The probability of a plant foraged for leaf is governed by its clade, family, nativity, and leaf dimension, particularly the leaf width. Bees have a clear preference for plants of common families, such as Fabaceae, Phyllanthaceae, and Meliaceae for foraging leaves, but bees going to plants of distant lineages, including rare species and families is not rare. At the same time, bees also avoided plants of several cosmopolitan families, such as Apocynaceae, Moraceae, Sapotaceae, and Asteraceae, among others. Bees preferred exotic plants more to native plants. The plant usage in communities is predicted by species richness, proportion of Fabaceae plants in communities, and proportion of herbs; plant diversity and abundance are not crucial drivers. Our study suggests that the bees' preference for leaf-foraging plants is not random, but governed by leaf, plant, and plant community traits. The preference for exotic plants is helpful for planning urban and homestead greening projects as they are dominated by exotics.

Kelp forests serve as the foundation for shallow marine ecosystems in many temperate areas of the world but are under threat from various stressors, including climate change. To better manage these ecosystems now and into the future, understanding the impacts of climate change and identifying potential refuges will help to prioritize management actions. In this study, we use a long-term dataset of observations of kelp percentage cover for two dominant canopy-forming species off the coast of Victoria, Australia: Ecklonia radiata and Phyllospora comosa. These observations were collected across three scuba sampling programs that extend from 1998 to 2019. We then associated those observations with habitat and environmental variables including depth, seafloor structure, wave climate, currents, temperature, and population connectivity in generalized additive mixed-effects models and used these models to develop predictive maps of kelp cover across the Victorian marine protected areas (MPAs). These models were also used to project kelp coverage into the future by replacing wave climate and temperature with future projections (2090, Representative Concentration Pathways [RCPs] 4.5 and 8.5). Once the spatial predictions were compiled, we calculated percent cover change from 1998 to 2019, stability over the same period, and future predicted change in percent cover (2019-2090) to understand the dynamics for each species across the MPAs. We also used the current percentage cover, stability, and future percentage cover to develop a ranking system for classifying the maps into very unlikely refugia, unlikely refugia, neutral, potential refugia, and likely refugia. A management framework was then developed to use those refugia ranking values to inform management actions, and we applied this framework across three case studies: one at the scale of the MPA network and two at the scale of individual MPAs, one where management decisions were the same for both species, and one where the actions were species-specific. This study shows how species distribution models, both contemporary and with future projections, can help to identify potential refugia areas that can be used to prioritize management decisions and future-proof restoration actions.

Determining the harvest location of timber is crucial to enforcing international regulations designed to protect natural resources and to tackle illegal logging and associated trade in forest products. Stable isotope ratio analysis (SIRA) can be used to verify claims of timber harvest location by matching levels of naturally occurring stable isotopes within wood tissue to location-specific ratios predicted from reference data ("isoscapes"). However, overly simple models for predicting isoscapes have so far limited the confidence in derived predictions of timber provenance. In addition, most use cases have limited themselves to differentiating between a small number of predetermined location options. Here, we present a new analytic pipeline for SIRA data, designed to predict the harvest location of a wood sample in a continuous, arbitrarily large area. We use Gaussian processes to robustly estimate isoscapes from reference wood samples, and overlay with species distribution data to compute, for every pixel in the study area, the probability of it being the harvest location of the examined timber. This is the first time, to our knowledge, that this approach is applied to determining timber provenance, providing probabilistic results rather than a binary outcome. Additionally, we include an active learning tool to identify locations from which additional reference data would maximize the improvement to model performance, allowing for optimisation of subsequent field efforts. We demonstrate our approach on a set of SIRA data from seven oak species in the United States as a proof of concept. Our method can determine the harvest location up to within 520 km from the true origin of the sample and outperforms the state-of-the-art approach. Incorporating species distribution data improves accuracy by up to 36%. The future sampling locations proposed by our tool decrease the variance of resultant isoscapes by up to 86% more than sampling the same number of locations at random. Accurate prediction of harvest location has the potential to transform worldwide efforts to enforce anti-deforestation legislation and protect natural resources.

Effective, practical options for managing disease in wildlife populations are limited, especially after diseases become established. Removal strategies (e.g., hunting or culling) are used to control wildlife diseases across a wide range of systems, despite conflicting evidence of their effectiveness. This is especially true for chronic wasting disease (CWD), an untreatable, fatal prion disease threatening cervid populations across multiple countries, for which recreational harvest has been suggested as an important disease control strategy. Using observational data to evaluate whether harvest effectively limits CWD prevalence has been difficult because statistical relationships between harvest and disease prevalence can arise from a causal effect of harvest (i.e., harvest's impacts on prevalence via changes in transmission or demographic structure) or from a number of alternative mechanisms. For instance, correlations between harvest and disease prevalence can also be driven by disease's impacts on population size and harvest (i.e., reverse causality) or from confounding variables (e.g., habitat or geographic location) that impact both harvest rates and disease prevalence. We analyzed two decades of surveillance data (2000-2021) from 10 mule deer herds in Wyoming, using statistical approaches informed by causal inference theory, to test for the effects of harvest on CWD prevalence. Herds with consistently high harvest pressure across 20 years had significantly lower prevalence. Our models predicted that harvesting 40% of adult males per year across 20 years would maintain prevalence below 5% on average, whereas if only 20% of males were harvested in each year, prevalence would increase to >30% by year 20. Moreover, shifting the relative harvest pressure within a herd over a shorter period (3 years) reduced subsequent prevalence, albeit to a smaller degree. Although high harvest is unlikely to completely eradicate CWD, our analysis suggests that maintaining hunting pressure on adult males is an important tactic for slowing CWD epidemics within mule deer herds. Our study also provides guidance for future analyses of longitudinal surveillance data, including the importance of demographic data and appropriate time lags.

As urban areas continue to expand globally, a deeper understanding of the functioning of urban green spaces is crucial for maintaining habitats that effectively support wildlife within our cities. Cities typically harbor a wide variety of nonnative vegetation, providing limited support for insect populations. The resulting scarcity of arthropods has been increasingly linked to adverse effects at higher trophic levels, such as the reduced reproductive success of insectivorous birds in urban environments. However, the responses by which urban breeding birds cope with the challenges of food limitation remain largely unexplored. To address this knowledge gap, in a Central European city, we employed radiotelemetry tracking and real-time observations on urban-breeding female great tits' habitat use, combined with detailed plant surveys and video recordings of nestlings' diet. This integrated approach enabled us to establish direct links between great tits' foraging behavior, vegetation preferences, and nestling diet. We found that besides tree canopies, great tits also frequently foraged on the ground and that the availability of bird feeders notably affected birds' habitat use. Foraging great tits generally avoided nonnative plants, particularly broadleaved species. When searching for nestling food, great tits were most time-efficient on conifers, albeit these trees provided low amounts of caterpillars (a preferred prey type). Great tits were more likely to forage on and deliver nestling food from large native trees and foraged less on and collected fewer prey items from the most abundant tree species. Our results underscore the importance of several factors that may help improve habitat quality for urban insectivorous birds, with preserving large trees and increasing diverse native vegetation being key elements in this endeavor.

Pathogens that infect multiple host species have an increased capacity to cause extinctions through parasite-mediated apparent competition. Given unprecedented and continuing losses of biodiversity due to Batrachochytrium dendrobatidis (Bd), the causative fungus of the amphibian skin disease chytridiomycosis, a robust understanding of the mechanisms driving cross-species infection dynamics is essential. Here, we used stage-structured, susceptible-infected compartmental models to explore drivers of Bd-mediated apparent competition between two sympatric amphibians, the critically endangered Litoria spenceri and the non-threatened Litoria lesueurii. We additionally simulated the impact of plausible L. spenceri conservation management interventions on competitive outcomes between these two species. Despite being more susceptible to disease than its competitor, a high relative rate of recruitment allowed the non-threatened L. lesueurii to reach substantially higher densities than L. spenceri in our baseline models, applying a strong absolute force of infection on L. spenceri as an amplifying host. However, simulated management interventions which bolstered L. spenceri recruitment (i.e., captive breeding and release, removal of predatory non-native trout) spurred strong recoveries of L. spenceri while simultaneously (1) increasing the force of Bd infection in the environment and (2) reducing L. lesueurii population density. At high and moderate elevations, combined captive breeding/release and non-native trout removal were sufficient to make L. spenceri the most abundant species. Overall, our results demonstrate the importance of recruitment in moderating pathogen dynamics of multi-host amphibian chytridiomycosis systems. While infection-based parameters are undoubtedly important in Bd management, modifying relative rates of recruitment can substantially alter pathogen-mediated competition between species of an amphibian community.

Tidal marshes can contribute to nature-based shoreline protection by reducing the wave load onto the shore and reducing the erosion of the sediment bed. To implement such nature-based shoreline erosion protection requires the ability to quickly restore or create highly stable and erosion-resistant tidal marshes at places where they currently do not yet occur. Therefore, we aim to identify the drivers controlling the rate by which sediment stability builds up in young pioneer marshes. Sediment stability proxies were measured over age gradients spanning 18 years in six tidal marsh sites in the Western Scheldt estuary (SW Netherlands): Three were dominated by Spartina anglica, a densely growing pioneer species, and three by Scirpus maritimus, a less densely growing pioneer species. Our results showed that the presence of densely growing Spartina anglica increased sediment shear strength compared to the unvegetated tidal flat, while less densely growing Scirpus maritimus did not. This difference may be related to the contrasting clonal expansion strategies and related root densities of these two pioneer species. Sediment stability did not increase further beyond 6 years of coverage by Spartina anglica, implying that the observed effect of Spartina anglica on sediment stability occurs fast (<6 years). Furthermore, sediment stability often increased with decreasing inundation duration and sediment water content. This study shows that in order to create erosion-resistant sediment beds in future marsh restoration projects, the aim should be to create densely vegetated tidal marshes with well-draining, cohesive sediments at relatively high intertidal elevation. Although the development of erosion resistance takes time, our study demonstrates that in the case of densely growing Spartina anglica marshes, increased sediment bed stability can already be reached after 6 years. The ability of Spartina anglica marshes to increase sediment bed stability within 6 years, in combination with wave attenuation and sediment accretion, offers promising perspectives to implement marsh restoration projects as a nature-based shoreline protection strategy that can start to deliver its protective service within a reasonable amount of time.

Fire shapes biodiversity in many forested ecosystems, but historical management practices and anthropogenic climate change have led to larger, more severe fires that threaten many animal species where such disturbances do not occur naturally. As predators, owls can play important ecological roles in biological communities, but how changing fire regimes affect individual species and species assemblages is largely unknown. Here, we examined the impact of fire severity, history, and configuration over the past 35 years on an assemblage of six forest owl species in the Sierra Nevada, California, using ecosystem-scale passive acoustic monitoring. While the negative impacts of fire on this assemblage appeared to be ephemeral (1-4 years in duration), spotted owls avoided sites burned at high-severity for up to two decades after a fire. Low- to moderate-severity fire benefited small cavity-nesting species and great horned owls. Most forest owl species in this study appeared adapted to fire within the region's natural range of variation, characterized by higher proportions of low- to moderate-severity fire and relatively less high-severity fire. While some species in this assemblage may be more resilient to severe wildfire than others, novel "megafires" that are larger, more frequent, and contiguously severe may limit the distribution of this assemblage by reducing the prevalence of low- to moderate-severity fire and eliminating habitat for a closed-canopy species for multiple decades. Management strategies that restore historical low- to moderate-severity fire with small patches of high-severity fire and promote a mosaic of forest conditions will likely facilitate the conservation of this assemblage of forest predators.

Large-scale restoration projects are an exciting and often untapped opportunity to use an experimental approach to inform ecosystem management and test ecological theory. In our $10M tidal marsh restoration project, we installed over 17,000 high marsh plants to increase cover and diversity, using these plantings in a large-scale experiment to test the benefits of clustering and soil amendments across a stress gradient. Clustered plantings have the potential to outperform widely spaced ones if plants alter conditions in ways that decrease stress for close neighbors. Here, we test whether intraspecific facilitation improves restoration outcomes using a suite of seven high marsh species native to central California salt marshes. We also applied a biochar treatment to test whether soil amendment boosts restoration success. We compared the performance of clustered and uniform plantings across the high marsh elevation gradient for 3 years. There was a strong effect of elevation on plant performance and clear signs of plant stress related to soil conditions. Clustering slightly improved the survival of one species out of seven, although clustering did not benefit that species in a follow-up experiment under more stressful conditions. By contrast, clustering had strong negative effects on the growth and/or cover of all species tested. The stressors in this system-likely related to compaction and soil salinity-were not mitigated by neighbors or biochar. The prevailing negative effect on seven species from distinct evolutionary lineages lends strong generality to our findings. We therefore conclude that for this and similar high marsh systems, intraspecific facilitation confers no benefits and practitioners should space plants widely to minimize competition. To take full advantage of the learning opportunities provided by large-scale restoration projects, we recommend including experimental treatments and monitoring the response of multiple species across years to refine best practices and inform adaptive management.

Plant vendors generate a commercial species pool, the subset of species in a regional flora that is purchasable. The availability of plant species from commercial vendors can influence the composition and outcomes of conservation, landscaping, and restoration plantings. Although previous research suggests that most plant species are unavailable, there is little information that identifies the plant characteristics associated with commercial availability. We studied the composition of the commercial species pool by examining the ecology, phylogeny, and phenology of a regional flora in the Midwestern United States. We used a database of native plant species sold by 557 vendors throughout the Midwest (USA) to characterize species' availability. We compiled ecological characteristics of all plant species, including range size, growth form, moisture requirements, and conservatism-meaning fidelity to high-quality natural areas. We characterized phenological (bloom time) data for a subset of the regional flora. Finally, we constructed a regional phylogeny to assess the phylogenetic signal of plant availability. We expected that commercially unavailable species would be niche specialists or short-lived (often nonconservative "weedy") species, and that they would bloom earlier in the season and for a shorter time. We found that commercially available species were more long-lived, had larger range sizes, had intermediate fidelities to wetlands and high-quality or disturbed natural areas, and were associated with certain plant types, especially shrubs and trees. In contrast, ferns and graminoids were underrepresented in the commercial trade. There was a strong phylogenetic signal associated with commercial availability; some plant families had nearly all or none of their species commercially available. Example families with low representation included Orchidaceae, Potamogetonaceae, Cyperaceae, and fern families. Longer bloomed species were more commercially available, but we did not find differences in availability between early- and late-blooming species. Despite the diversity of the commercial pool in the Midwest, it is an unrepresentative, nonrandom subset of the regional species pool. This finding may promote the mismatch in species diversity and composition between remnant natural habitats and restorations because many specialized species are commercially unavailable to conservation and restoration practitioners. We encourage strategies to promote the availability of underrepresented plant diversity in the commercial species pool.

Plastic pollution threatens almost every ecosystem in the world. Critically, many animals consume plastic, in part because plastic particles often look or smell like food. Plastic ingestion is thus an evolutionary trap, a phenomenon that occurs when cues are decoupled from their previously associated high fitness outcomes. Theory predicts that dominance hierarchies could dictate individual responses to evolutionary traps across social environments, but the social dimension of evolutionary trap responses has rarely been investigated. We tested how variation in group size influences the formation of dominance relationships and, in turn, how these dominance relationships drive differences in foraging behavior in Western mosquitofish (Gambusia affinis). This included foraging for a variety of familiar and novel food-like items, including microplastics. Overall, dominant individuals were often the first to sample food and had higher bite rates than subordinates, including when foraging for microplastics. Importantly, how dominance affected foraging behavior depended on group size and on whether groups were presented with familiar or novel foods. Furthermore, individuals were consistent in their foraging behavior across trials with different group sizes, indicating the formation of stable social roles. These results suggest that predicting the ecological and evolutionary consequences of evolutionary traps will require an understanding of how social structures influence trap susceptibility.

Climate change is one of the largest threats to grassland plant species, which can be modified by land management. Although climate change and land management are expected to separately and interactively influence plant demography, this has been rarely considered in climate change experiments. We used a large-scale experiment in central Germany to quantify the effects of grassland management, climate change, and their joint effect on the demography and population growth rate of 11 plant species all native to this temperate grassland ecosystem. We parameterized integral projection models with five years of demographic data to project population growth rate. We hypothesized that plant populations perform better in the ambient than in the future climate treatment that creates hotter and drier summer conditions. Further, we hypothesized that plant performance interactively responds to climate and land management in a species-specific manner based on the drought, mowing, and grazing tolerances as well as the flowering phenology of each species. Due to extreme drought events, over half of our study species went quasi extinct, which highlights how extreme climate events can influence long-term experimental results. We found no consistent support for our expectation that plants perform better in ambient compared with future climate conditions. However, several species showed interactive responses to the treatments, indicating that optimal management strategies for plant performance are expected to shift with climate change. Changes in population growth rates of these species across treatments were mostly due to changes in plant reproduction. Experiments combined with measuring plant demographic responses provide a way to isolate the effects of different drivers on the long-term persistence of species and to identify the demographic vital rates that are critical to manage in the future. Our study suggests that it will become increasingly difficult to maintain species with preferences for moister soil conditions, and that climate and land use can interactively alter demographic responses of the remaining grassland species.

Grazing by large mammalian herbivores influences ecosystem structure and functions through its impacts on vegetation and soil, as well as by the influence on other animals such as arthropods. As livestock progressively replace native grazers around the world, it is pertinent to ask whether they have comparable influence over arthropods, or not. We use a replicated landscape-level, long-term grazer-exclusion experiment (14 years) to address how ground-dwelling arthropods respond to such a change in grazing regime where livestock replace native grazers in the cold deserts of the Trans-Himalayan ecosystem of northern India. We analyze spatial and temporal variation in the abundance of 25,604 arthropods sampled using pitfall traps across 2765 trap-days through the duration of the growing season spanning spring, summer, and autumn. These were from 88 operational taxonomic units covering six orders from 33 families (ants, wasps, bees, ticks and mites, spiders, grasshoppers, and beetles). We find that grazer assemblage-whether livestock or native herbivores-had a strong influence on both vegetation and arthropods. Partial redundancy analysis (RDA) showed that 53.6% of the spatial and temporal variation in arthropod communities could be explained by grazing and by grazer assemblage identity, alongside covariation with vegetation composition and soil variables. Structural equation models revealed that grazing and grazer assemblage identity have direct effects on arthropods, as well as indirect effects that are mediated through vegetation. Importantly, spiders (predators) were less abundant under livestock, whereas grasshoppers (leaf eaters) and ticks and mites (parasitic disease vectors) were more abundant, compared with native grazers. Reduction in spiders can fundamentally alter material and energy flow through the cascading effects of losing predators, and an abundance of grasshoppers may even contribute to vegetation degradation that is often associated with livestock. Parallelly, increases in ticks and mites lead to concerns over vector-borne disease that require planned interventions to align animal husbandry with One Health. Thus, losing native grazers to livestock expansion can have wide-ranging repercussions via arthropods. This may not only affect ecosystem structure and functions, but also offer challenges and opportunities to mitigate risks from vector-borne disease.