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The global loss of biodiversity has inspired actions to restore nature across the planet. Translocation and social attraction actions deliberately move or lure a target species to a restoration site to reintroduce or augment populations and enhance biodiversity and ecosystem resilience. Given limited conservation funding and rapidly accelerating extinction trajectories, tracking progress of these interventions can inform best practices and advance management outcomes. Seabirds are globally threatened and commonly targeted for translocation and social attraction (“active seabird restoration”), yet no framework exists for tracking these efforts nor informing best practices. This study addresses this gap for conservation decision makers responsible for seabirds and coastal management. We systematically reviewed active seabird restoration projects worldwide and collated results into a publicly accessible Seabird Restoration Database. We describe global restoration trends, apply a systematic process to measure success rates and response times since implementation, and examine global factors influencing outcomes. The database contains 851 active restoration events in 551 locations targeting 138 seabird species; 16% of events targeted globally threatened taxa. Visitation occurred in 80% of events and breeding occurred in 76%, on average 2 y after implementation began (SD = 3.2 y). Outcomes varied by taxonomy, with the highest and quickest breeding response rates for Charadriiformes (terns, gulls, and auks), primarily with social attraction. Given delayed and variable response times to active restoration, 5 y is appropriate before evaluating outcomes. The database and results serve as a model for tracking and evaluating restoration outcomes, and is applicable to measuring conservation interventions for additional threatened taxa. more...

On isolated islands, large arthropods can play an important functional role in ecosystem dynamics. On the Norfolk Islands group, South Pacific, we monitored the diet and foraging activity of an endemic chilopod, the Phillip Island centipede ( more...

Seabirds influence island ecosystems through nutrient additions and physical disturbance. These influences can have opposing effects on an island's invertebrate predator populations. Spiders (order: Araneae) are an important predator in many terrestrial island ecosystems, yet little is known about how seabird presence influences spider communities at the intraisland scale, or how they respond to seasonality in seabird colony attendance.We investigated the effects of seabird presence and seasonality on ground-active spider community structure (activity-density, family-level richness, age class, and sex structure) and composition at the family-level across five short-tailed shearwater breeding islands around south-eastern Tasmania, Australia. Using 75 pitfall traps (15 per island), spiders were collected inside, near, and outside seabird colonies on each island, at five different stages of the short-tailed shearwater breeding cycle over a year. Pitfall traps were deployed for a total of 2674 days, capturing 1592 spiders from 26 families with Linyphiidae and Lycosidae the most common. Spider activity-density was generally greater inside than outside seabird colonies, while family-level richness was generally higher outside seabird colonies. For these islands, seabird breeding stage did not affect activity-densities, but there were some seasonal changes in age class and sex structures with more adult males captured during winter. Our results provide some of the first insights into the spatial and temporal influences seabirds have on spider communities. We also provide some of the first records of spider family occurrences for south-eastern Tasmanian islands, which will provide an important baseline for assessing future change. more...

Biological invasions resulting from anthropogenic activities are one of the greatest threats to maintaining ecosystem functioning and native biodiversity. Invasions are especially problematic when the invading species behaves as an ecosystem engineer that is capable of transforming ecosystem structure, function, and community dynamics. Of particular concern is the spread of emergent wetland grasses whose root systems alter hydrology and structural stability of soils, modify ecosystem functions, and change community dynamics and species richness. To address the threats posed to ecosystems across the globe, management practices focus on the control and removal of invasive grasses. However, it remains unclear how severely invasive grasses alter ecosystem functions and whether alterations persist after invasive grass removal, limiting our ability to determine if management practices are truly sufficient to fully restore ecosystems. Here, we conducted a meta-analysis to quantify ecological alterations and the efficacy of management following the invasion of Spartina alterniflora and Phragmites australis, two common and pervasive invaders in coastal wetlands. Our results indicate that S. alterniflora and P. australis significantly alter measures of ecosystem functioning and organismal abundance. Invaded ecosystems had significant elevations in abiotic carbon and nitrogen fixation and uptake in areas with invasive grasses, with differential photosynthetic pathways of these two grass species further explaining carbon fluxes. Moreover, evidence from our analyses indicates that management practices may not adequately promote recovery from invasion, but more data are needed to fully assess management efficacy. We call for future studies to conduct pairwise comparisons between uninvaded, invaded, and managed systems and provide research priorities. more...

Moonlight structures activity patterns of many nocturnal species. Bright moonlight often limits the activity of nocturnal prey, but dense vegetation weakens this effect. Using 8 years of live-trapping data, we asked whether reintroduced megaherbivores (Bison bison) indirectly altered moonlight avoidance by small mammals in tallgrass prairies. In plots with bison, plants intercepted 20% less light, allowing more moonlight to reach ground level. During nights with no moonlight, Peromyscus maniculatus activity was similar in plots with and without bison. During nights with peak moonlight, P. maniculatus activity was four times greater in plots without bison compared to plots with bison. Conversely, Microtus ochrogaster activity was twice as great during full moons compared to new moons, but only in plots with bison. We also equipped a subset of traps with temperature sensors to estimate trap-entry time. Although M. ochrogaster was more active on bright nights, most activity occurred before moonrise or after moonset, avoiding periods of bright moonlight. We conclude that megaherbivores play an unappreciated but important indirect role in tallgrass prairies by inducing behavioral shifts in other animal species. Because overlap in activity patterns can predict the likelihood of predator-prey encounters, such activity shifts have important implications for trophic interactions throughout restored prairie food webs. Additional work to understand interspecific and intraspecific variation in response to moonlight may improve efforts to forecast changes in community assembly due to restoration and land-use change. more...

Seabirds maintain island ecosystem function by providing rich marine-derived nutrients to the islands where they nest. These nutrients are returned to the sea through runoff, fertilizing the nearshore environment. Invasive predators disrupt this bottom-up control by decimating seabird populations. While invasive predator eradications lead to terrestrial recovery on seabird islands, there is little information on the nearshore impact. We determined how nearshore macroalgae communities and seabird-derived nitrogen concentrations are influenced by predator eradications and environmental parameters (sampling depth, season, wave exposure, and runoff). This case study examined 4 islands in the Mercury Islands archipelago, representing 3 eradication histories: never invaded by mammalian predators, eradicated over 30 yr ago, and eradicated 2 yr ago. Macroalgal diversity was highest at never-invaded islands, followed by islands in order of eradication year (eradicated 30 and 2 yr ago). The amount of seabird-derived nitrogen (δ15N) in algae was higher during the rainy season and decreased with sampling depth and wave exposure. Sampling near high runoff points resulted in increased δ15N in red algae alone. Never-invaded islands had the highest δ15N in most species. With species found at both eradicated islands, the recently eradicated island had unexpectedly higher δ15N than the island eradicated over 30 yr ago. This discrepancy may be a result of the recently eradicated island’s large size and presence of streams, estuaries, and sheltered bays. Studying nearshore habitats is crucial in understanding the extent to which seabirds act as a conduit of the land-sea interface and the marine impacts of island management. more...

Grassland bird responses to grazing and prescribed fire are species-specific and are primarily known from systems with cattle as the predominant grazer. There is less knowledge of how grazing by bison impacts grassland birds, especially in sites restored and reconstructed from row-crop agriculture. Working at a tallgrass prairie site consisting of restored and remnant prairie in the years following bison reintroduction and ongoing prescribed burning, we assessed overall species richness and the relative detection frequency of five focal species (Grasshopper Sparrow, Henslow's Sparrow, Dickcissel, Eastern Meadowlark, and Brown-headed Cowbird). We used stationary bioacoustics recorders to record the soundscape during the summer breeding season in areas with and without bison from 2016 to 2018. Species richness and the detection frequencies of our focal species were not influenced by bison disturbance. Grasshopper Sparrow and Dickcissel detection frequency increased slightly in response to prescribed fire, whereas Henslow's Sparrow detection frequency decreased. Time since sites were restored was a predominant factor that influenced the variation in detection frequency of Henslow's Sparrows and Eastern Meadowlarks, likely due to vegetation differences in restored versus remnant sites and each species' vegetation structure preferences. Brown-headed Cowbird detection frequency was unaffected by bison presence, prescribed fire, or time since restoration, but varied among sampling years. Our focal species showed no response to bison disturbance 4 y after the bison reintroduction. This suggests there could be a time-lag for a response or that these species will not respond to the bison reintroduction at this study site. more...

Spatial structure of species change Biodiversity is undergoing rapid change driven by climate change and other human influences. Blowes et al. analyze the global patterns in temporal change in biodiversity using a large quantity of time-series data from different regions (see the Perspective by Eriksson and Hillebrand). Their findings reveal clear spatial patterns in richness and composition change, where marine taxa exhibit the highest rates of change. The marine tropics, in particular, emerge as hotspots of species richness losses. Given that human activities are affecting biodiversity in magnitudes and directions that differ across the planet, these findings will provide a much needed biogeographic understanding of biodiversity change that can help inform conservation prioritization. Science , this issue p. 339 ; see also p. 308 more...

Community assembly changes fundamentally in response to disturbance following habitat destruction due to extreme events and human activities. There are several important aspects of community assembly that can be measured in response to disturbance or during species establishment. Of these measurable outcomes, metrics of taxonomic or species diversity (SD) are perhaps the most common and logistically the easiest to evaluate. It is increasingly evident that measurements of phylogenetic (PD) and functional trait (FD) diversity can provide more information than traditional measures of diversity and desirable and informative metrics to measure restoration outcomes. However, it is unclear whether FD and PD are drivers or a consequence of community assembly. This Special Feature highlights eight field studies and a review that have investigated how PD diversity and functional trait diversity can be used to better understand grassland community assembly following disturbance or during restoration, and how as potential drivers they can be manipulated experimentally or incorporated into evolutionary models. Topics include: colonizing species as a function of FD and PD; dominant species origin impacts on subordinate species FD; impacts of environmental gradients such as seed mix richness, first‐year precipitation and restoration age on FD and taxonomic diversity; impacts of drought and resource availability; and a synthesis of studies that measured FD and PD to determine if they provide similar or incongruent inferences for ecological and functional processes. The work in this Special Feature indicates that SD, FD and PD can act as drivers and passengers of community assembly, and often yield different insights. Environmental gradients such as soil nutrients, precipitation and environmental drivers like drought can influence FD and PD of assembling communities in predicted and unexpected ways. Synthesis. Results from the studies in this Special Feature highlight the importance of considering a multitude of ecological and evolutionary drivers of community assembly in grassland ecosystems. Studies pushing this field forward will be those that incorporate or study higher trophic levels, realistically incorporate climate change and disentangle the impacts of FD and PD. more...

Invertebrates are key to island ecosystems but impacts from invasive mammalian predators are not well documented or understood. Given this knowledge gap, we studied terrestrial arthropod communities in the presence of a common invasive rodent (house mice, Mus musculus) on a subtropical atoll—Midway Atoll National Wildlife Refuge (MANWR). Here, invasive mice recently began to attack and depredate nesting seabirds, prompting planning for a future mouse eradication. However, uncertainty remains regarding the ecosystem's response to mouse removal. As part of a pre-eradication investigation, we conducted a baseline survey of MANWR's arthropod community structure and diversity (at order level), comparing islands with and without mice. From April 2018 to February 2020, we used pitfall traps to monitor ground-dwelling arthropods on MANWR's Sand Island (mice present) and Eastern Island (mice absent). During our study, we captured over 450,000 specimens from 24 taxonomic units. Arthropods on MANWR form six community clusters and differ between islands and habitats. Richness is relatively similar among clusters and islands, but diversity of common and dominant arthropod taxa is significantly higher on Sand Island, as well as in anthropogenically-built habitats. Weather is not a strong environmental driver of arthropod communities; community structure and diversity vary only slightly throughout the year. Additionally, anthropomorphic landscape-level alteration of MANWR may still influence arthropod communities today. Continued monitoring and research will provide better insight into how arthropod communities recover following invasive mouse eradications. Our study contributes to the body of knowledge of arthropods in the Northwestern Hawaiian Islands, arthropod community ecology, and potential mouse impacts on islands. more...

Monitoring seabird‐derived nutrients on islands following invasive mammal eradications may provide a useful, cost‐ and time‐efficient indication of the recovery of ecosystem function; however, the technique has only been investigated on environmentally similar islands. How seabird‐derived nutrients recover on islands with different characteristics, and how differences in sampling regimes affect results is poorly understood. To determine how different island characteristics (size, geographic location and invasion history) and aspects of the sampling regime (sample collection year, season and intra‐island location) influence seabird‐derived nutrients we collated nitrogen stable isotope (δ15N) data from three ecosystem components (soil, plants and spiders), collected on 28 islands around New Zealand. We investigated which variables best predict δ15N using linear‐mixed effects models. Accounting for these variables and using still‐invaded and never‐invaded islands as controls for recovery, we then investigated changes in δ15N on islands at different stages following invasive mammal eradication. Island size, invasion history and the presence of seabirds in the direct vicinity of a sampling location all influenced δ15N. After accounting for these variables, δ15N increased with time since eradication in soils, plants and spiders, though there was still some variation that our chosen variables could not explain. This study demonstrates the importance of considering island characteristics and sampling methods when assessing seabird‐derived nutrient recovery and highlights the need for additional targeted sample collection on islands to help separate out the effects of time since eradication and other confounding variables affecting δ15N. Improved understanding of these factors will be prerequisite for furthering this technique as a useful addition to the post‐eradication monitoring tool kit. more...

The majority of tallgrass prairie has been converted to agriculture over the past two centuries. Restoration projects have sought to increase the quality and size of prairie fragments, with the potential to increase grassland breeding bird habitat. American bison (Bison bison) are being reintroduced to prairie restoration sites and the immediate impacts of these reintroductions are unclear. Our goal was to understand how bison reintroduction influences grassland bird nests and the potential mechanisms behind any change. We measured nest density, nest success, and brood parasitism with a before-after-control-impact (BACI) design to determine if bison influenced pooled nesting success of breeding passerines and field sparrows (Spizella pusilla), the most common nester. In addition, we measured visual obstruction and avian species composition to determine if they changed after the reintroduction. Bison did not influence nest density, brood parasitism, or visual obstruction. Pooled nest success was higher during the first 2 y in bison sites after the reintroduction but decreased the following 2 y. Bird species composition differed slightly between areas with and without bison, but this was not due to the reintroduction and was likely due to other site characteristics. Field sparrow nest success was higher before and after reintroduction in bison sites and drove the pooled nest success results in bison sites. Caution should be taken when interpreting pooled nest data, but these results suggest that bison did not negatively impact nest success of grassland nesting birds immediately following their reintroduction ( more...

Ecosystem restoration is a critical component of land management, countering the loss of native biodiversity. Restoration efforts are enhanced by reintroducing naturally occurring ecosystem processes, including disturbances that may impact species characteristics such as niche position or niche size. In grasslands, grazing and fire affect plant diversity and habitat complexity, which potentially influence insect dietary behaviors and thus their contributions to functions like seed and arthropod predation. Using carbon and nitrogen stable isotopes, we characterized variation in the dietary niche of six ground beetle species (Coleoptera: Carabidae) in response to grazing by reintroduced bison and prescribed fire disturbances in twenty tallgrass prairies. Management disturbances did not affect activity density for most beetle species and mean trophic position was mostly unaffected. However, five of six species exhibited increased trophic niche area and breadth with disturbances, indicating a switch to a more generalist diet that incorporated a wider range of food items. The combination of bison and fire impacts may increase vegetation patchiness and heterogeneity, driving these diet changes. Morphological traits and microhabitat preferences might mediate response to disturbances and the resulting heterogeneity. Combining prescribed fire and grazing, which increases plant diversity and vegetation structural diversity, may help beetle communities establish over time and support the ecological functions to which these insects contribute. more...

A primary goal of ecological restoration is to increase biodiversity in degraded ecosystems. However, the success of restoration ecology is often assessed by measuring the response of a single functional group or trophic level to restoration, without considering how restoration affects multitrophic interactions that shape biodiversity. An ecosystem-wide approach to restoration is therefore necessary to understand whether animal responses to restoration, such as changes in biodiversity, are facilitated by changes in plant communities (plant-driven effects) or disturbance and succession resulting from restoration activities (management-driven effects). Furthermore, most restoration ecology studies focus on how restoration alters taxonomic diversity, while less attention is paid to the response of functional and phylogenetic diversity in restored ecosystems. Here, we compared the strength of plant-driven and management-driven effects of restoration on four animal communities (ground beetles, dung beetles, snakes, and small mammals) in a chronosequence of restored tallgrass prairie, where sites varied in management history (prescribed fire and bison reintroduction). Our analyses indicate that management-driven effects on animal communities were six-times stronger than effects mediated through changes in plant biodiversity. Additionally, we demonstrate that restoration can simultaneously have positive and negative effects on biodiversity through different pathways, which may help reconcile variation in restoration outcomes. Furthermore, animal taxonomic and phylogenetic diversity responded differently to restoration, suggesting that restoration plans might benefit from considering multiple dimensions of animal biodiversity. We conclude that metrics of plant diversity alone may not be adequate to assess the success of restoration in reassembling functional ecosystems. more...

To redress prairie loss, managers seed former agricultural lands and reinstate key ecosystem processes with prescribed fires and reintroduction of native grazers to create restored prairies. Bison (Bison bison) were almost hunted to extinction in the late 1800s but are recovering and have recently been reintroduced to restored prairies for their ecosystem engineering roles. The effects bison and fire have on remnant (never-plowed) prairie vegetation are well documented. However, there is little known about how bison will impact plant communities in restored prairies. These effects are most likely driven by reduction of competition from grasses and increased heterogeneity from disturbance. This study aimed to quantify bison impacts on vegetation in a chronosequence of restored prairie with varied burning regimes. We found that plant diversity decreased with restoration age and did not differ among either grazing or fire treatments. However, grazed sites displayed more variation within plant community composition. Older restorations tended to be more similar in species and functional group composition in comparison to younger sites. Although the roles of bison and fire were not as important in these first three years after reintroduction as predicted, changes in composition suggest that bison effects may become more apparent in later years as grazing drives different compositional trajectories. more...

Grazing differentially affects both the abundance and breeding success of grassland birds (e.g., due to differences in bird species' preferences for sparse or dense vegetation structure, nest predator response to grazing, and/or trampling of nests). Coupled with prescribed fire, grazing impacts can be compounded by pyric herbivory—the preference of grazers to choose newly-burned sites in which to graze. The purpose of this study was to determine how a recent re-introduction of American bison (Bison bison) coupled with prescribed fire may impact grassland bird nests. Artificial nests were used to determine if grazing and fire impacted nest success, total mammalian depredation, and depredation by the most common nest predator, mice (Peromyscus spp.). Artificial nests were placed in sites with and without bison before (2014) and after bison re-introduction (2015–2018); sites had fire return intervals from 1–2 y. We found the re-introduction of bison had a negligible influence on nest success and total mammalian depredation. However, nest success was lower in burned sites compared to unburned sites. The decrease in nest success correlated with an increase in total proportion of depredation events in burned sites compared to unburned sites. In addition, the proportion of Peromyscus spp. depredation events was marginally higher in burned sites compared to unburned sites. Although predation by Peromyscus increased after bison re-introduction, prescribed fire differences drove this change. Our results suggest prescribed fire may increase nest predation of artificial nests, indicating a possible impact on ground-nesting grassland birds. In contrast, bison had a negligible impact on artificial nest success in the first 4 y following their re-introduction. more...

Grazing as a management tool is often intended to alter plant community dynamics through preferential foraging. Bison diet in the western United States has been well studied, especially in short and mixed grass remnant prairies. However, there is little known about what bison consume in restored and tallgrass prairies. As bison reintroductions are used more commonly in eastern tallgrass prairies, it is important to understand their diet to predict future impacts on prairie plant communities. This study aims to understand bison diet across different seasons, and asks whether diet differs among male and female, and differently aged bison. We used stable isotope analysis to quantify δ¹³C and δ¹⁵N in plants and used a Bayesian isotope mixing model to estimate bison diet. We found bulls relied more heavily on C₄ plants and wetland plants than cows, which relied more heavily on forbs, but no differences in diet between ages. Our analysis shows that bison primarily grazed on C₄ grasses throughout the late spring and summer. However, bison foraged more on wetland species and forbs in the late summer and fall. This change in diet could have implications for wetland species and habitats, through dung inputs and trampling. The relatively high reliance on forbs for nearly one‐third of bison diet could mean intended impacts of reintroduced bison such as increased plant diversity through preferential grazing on grasses could be dampened. Managers reintroducing bison to restored prairie ecosystems should ensure adequate wetland and forb species, in addition to a mix of grasses. more...

Unpredictable or variable ecosystem recovery from disturbance presents a challenge to conservation, particularly as the scale of human disturbance continues to increase. Theory suggests land-cover and disturbance characteristics affect recovery, but individual studies of disturbance and recovery frequently struggle to uncover generalizable patterns because of high levels of site-specific variation. To understand how land-cover, disturbance type, and disturbance duration influence ecosystem recovery, we used studies documenting recovery of 50 streams to perform a global meta-analysis of stream recovery from disturbances that affect water quality (e.g., oil spill, fire, wastewater). We extracted upstream natural and urban land-cover percentages for each site and performed model selection and averaging to identify influences on recovery completeness. Most streams improved following the end of a disturbance (median 240% of disturbed condition) but did not recover fully to baseline predisturbance condition within the studied period (median study period 2 years; median recovery 60% of baseline). Scale of disturbance in time and space did not predict recovery, but sites with higher percentages of upstream natural land cover had less complete recovery relative to sites with more urban or agricultural cover, possibly due to higher baseline conditions in these streams. Our findings suggest impacts to systems with low anthropogenic stress may be more irreversible than impacts to already modified systems. We call for more long-term evaluations of ecosystem response to disturbance and the inclusion of regional references and predisturbance reference conditions for comparison. A more thorough understanding of the role of the surrounding landscape in shaping stream response to disturbance can help managers calibrate expectations for recovery and prioritize protection.Meta-Análisis de los Efectos de la Cobertura Río-Arriba sobre la Restauración de Arroyos Resumen La restauración impredecible o variable de un ecosistema después de una perturbación presenta un reto para la conservación, particularmente conforme la escala de perturbaciones humanas continúa incrementando. La teoría sugiere que la cobertura de suelo y las características de la perturbación afectan a la restauración pero los estudios individuales sobre las perturbaciones y las restauraciones constantemente luchan por descubrir patrones generalizables debido a los niveles altos de variación específica en el sitio. Usamos estudios que documentan la restauración de 50 arroyos para realizar un meta-análisis global de la restauración de arroyos después de perturbaciones que afectaron la calidad del agua (p. ej.: derrames de petróleo, incendios, aguas negras) y así entender cómo la cobertura de suelo, el tipo de perturbación, y la duración de la perturbación influyen sobre la restauración del ecosistema. Extrajimos porcentajes de la cobertura natural y urbana de suelo río-arriba para cada sitio y realizamos una selección y promedio de modelos para identificar las influencias sobre la completitud de la restauración. La mayoría de los arroyos mejoraron después de que terminó la perturbación (mediana del 240% de la condición perturbada) pero no se recuperó completamente hasta la línea base de condiciones previas a la perturbación dentro del periodo estudiado (mediana del periodo de estudio: dos años; mediana de la restauración 60% de la línea base). La escala de perturbación en el tiempo y en el espacio no pronosticó la restauración, pero los sitios con porcentajes más altos de cobertura natural de suelo río-arriba tuvieron una restauración menos completa en relación con los sitios con una cobertura más urbana o agrícola, posiblemente debido a las condiciones más altas de línea base en estos arroyos. Nuestros hallazgos sugieren que los impactos sobre los sistemas con un bajo estrés antropogénico pueden ser más irreversibles que los impactos sobre sistemas que ya han sido modificados. Hacemos un llamado por más evaluaciones a largo plazo de la respuesta de los ecosistemas ante las perturbaciones y por la inclusión de referencias regionales y condiciones previas a la perturbación como referencia para realizar comparaciones. Un entendimiento más a fondo del papel del paisaje circundante en la formación de la respuesta de los arroyos ante las perturbaciones puede ayudar a los administradores a calibrar expectativas para la restauración y a priorizar la protección.受到干扰后难以预测、多变的生态系统恢复情况给保护带来挑战, 特别是考虑到人类干扰的尺度还在持续扩大。理论表明, 土地覆盖和干扰的特征会影响恢复, 但由于各受干扰位点特异性变化大, 对干扰和恢复的单个研究常常难以发现一般规律。为理解土地覆盖、干扰类型和干扰持续时间如何影响生态系统恢复, 我们用 50 条河流的恢复研究, 对全球河流受到影响水质的干扰 (如石油泄漏、火灾、废水排放) 后的恢复情况进行了集合分析。我们提取了每个位点上游的自然和城市景观的土地覆盖比例, 并通过模型选择和模型平均确定了恢复程度的影响因素。大多数河流在干扰结束后都能恢复改善 (中位数:达到干扰状态的 240%) , 但在研究期间不能完全恢复到干扰前的基线水平 (中位数:研究时长为2年;恢复到基线水平的 60%) 。干扰的时空尺度不能预测恢复情况, 但相比于上游城市或农业土地覆盖比例高的位点, 自然土地覆盖比例高的位点更难恢复, 可能是因为这样的河流流域的基线水平较高。我们的研究结果表明, 人类影响弱的系统受到干扰后可能比已被改造的系统更难逆转。我们呼吁进行更多的生态系统对干扰响应的长期评估, 并纳入区域性参照和干扰前参照以作比较。深入理解周围景观在塑造河流对干扰的响应中的作用还可以帮助管理者调整对恢复的预期和规划优先保护。翻译: 胡怡思; 审校: 聂永刚. more...

Non-hominid primates (NHPs) are some of the most understudied invasive mammals in terms of their impacts to biodiversity and the ability to successfully manage them, despite their having been implicated in numerous extinctions. We found 99 NHP populations of 37 species have been introduced on at least 67 islands and various mainland locations. NHPs have been implicated in at least 69 extinctions or extirpations. NHPs reduce human food security, display aggressive behavior sometimes resulting in human fatalities, and transmit diseases. We identified thirty islands where management is likely feasible and rank them by the potential biodiversity benefits of NHP management. At least eight attempts to eradicate NHP populations have been made with only one so far having been successful. Social considerations along with technological advancements in management methods are both needed to curb the impacts of NHPs and protect people and biodiversity on islands invaded by NHPs. more...

Ecosystem restoration provides unique opportunities to study community dynamics under succession and can reveal how consumer communities re-assemble and respond to successional changes. Studying community dynamics from both taxonomic and functional trait perspectives also may provide more robust assessments of restoration progress or success and allow cross-system comparisons. We studied ground beetle (Coleoptera: Carabidae) communities for three years in a restored grassland chronosequence with sites from 0 to 28 years old. We measured traditional community metrics (abundance, richness, Shannon diversity) and functional trait metrics based on species’ body length, wing morphology, activity time, phenology, and diet. Communities had high species richness and abundance in early successional stages, but these declined in later stages to low levels comparable to an adjacent grassland remnant. Species composition also shifted with time, converging with the remnant. Although functional richness, like species richness, declined as succession progressed, functional divergence quickly increased and was maintained over time, suggesting niche differentiation in established communities. Young sites were typified by small, macropterous, phytophagous species, while older sites contained larger species more likely to be flightless and carnivorous. Prescribed burns also affected traits, decreasing prevalence of larger species. This study demonstrates that functionally diverse consumer communities can self-assemble under restoration practices. In a relatively short amount of time both morphological and trophic level diversity are established. However, prescribed fire intended to control non-desirable plants may also shape beetle community functional composition, and restoration managers should consider if plant community benefits of fire outweigh potential declines in consumer function. more...

Domestic cats (Felis catus) are one of the world’s most damaging invasive species. Free-ranging cats kill billions of wild animals every year, spread parasites and diseases to both wildlife and humans, and are responsible for the extinction or extirpation of at least 63 species. While the ecology and conservation implications of free-ranging cats have well studied in some locations, relatively little is known about cats inhabiting urban nature preserves in the United States. To address this knowledge gap, we used camera traps to study the occupancy and activity patterns of free-ranging cats in 55 suburban nature preserves in the Chicago, IL metropolitan area. From 2010–2018 (4,440 trap days), we recorded 355 photos of free-ranging cats across 26 preserves (ψnaïve= 0.45) and 41 randomly distributed monitoring points (ψnaïve= 0.18). Cats were detected every year, but rarely at the same point or preserve, and cats were largely crepuscular/diurnal. Using single-season occupancy models and a “stacked” design, we found that cat occupancy increased with building density and detectability was highest near the urban/preserve boundary. Based on our top-ranked model, predicted occupancy within individual preserves ranged from 0.09 to 0.28 (ψmean= 0.11) and was poorly correlated with preserve size or shape. Overall, our results suggest that free-ranging cats are rare within suburban preserves in our study area, and that these cats are most likely owned or heavily subsidized by people (which pose different risks and management challenges than truly feral cats). We discuss the conservation and management implications for urban natural areas.HighlightsWe surveyed for domestic cats across 55 suburban preserves from 2010-2018.We modeled occupancy and detectability as a function of urban covariates.Cat occupancy was low overall and best predicted by building density.The risk to native species is highest near preserve boundaries bordered by built environments. more...

Ecological restoration seeks to reestablish functioning ecosystems, but planning and evaluation often focus on taxonomic community structure and neglect consumers and their functional roles. The functional trait composition of insect assemblages, which make up the majority of animal diversity in many systems, can reveal how they are affected by restoration management and the consequences for ecosystem function. We sampled ground beetle (Coleoptera: Carabidae) assemblages in restored tallgrass prairies varying in management with prescribed fire and reintroduced American bison (Bison bison) to describe their taxonomic and functional trait structure. We also measured seed and arthropod predation to relate management, beetle assemblage characteristics, and function, and to test if function is maximized by trait diversity, dominant trait values, or beetle abundance. Beetle assemblages primarily varied with restoration age, declining over time in richness and both taxonomic and functional diversity, but bison presence also influenced taxonomic composition. Prescribed fire reduced seed predation in summer and arthropod predation in fall. Although seed predation was unrelated to beetle assemblages, arthropod predation was greater in sites with higher abundances of carnivorous ground beetles. The relatively weak impacts of fire and bison on functional assemblage structure is a promising sign that these management disturbances, aimed at supporting a diverse native plant community, are not detrimental to beetle assemblages. The significance of reduced predator function following prescribed fire will depend on the restoration context and whether seed or arthropod predation relates to management goals. more...

Helping the world's coastal communities adapt to climate change impacts requires evaluating the vulnerability of coastal communities and assessing adaptation options. This includes understanding the potential for 'natural' infrastructure (ecosystems and the biodiversity that underpins them) to reduce communities' vulnerability, alongside more traditional 'hard' infrastructure approaches. Here we present a spatially explicit global evaluation of the vulnerability of coastal-dwelling human populations to key climate change exposures and explore the potential for coastal ecosystems to help people adapt to climate change (ecosystem-based adaptation (EbA)). We find that mangroves and coral reefs are particularly well situated to help people cope with current weather extremes, a function that will only increase in importance as people adapt to climate change now and in coming decades. We find that around 30.9 million people living within 2km of the coast are highly vulnerable to tropical storms and sea-level rise (SLR). Mangroves and coral reefs overlap these threats to at least 5.3 and 3.4 million people, respectively, with substantial potential to dissipate storm surges and improve resilience against SLR effects. Significant co-benefits from mangroves also accrue, with 896 million metric tons of carbon stored in their soils and above- and below-ground biomass. Our framework offers a tool for prioritizing 'hotspots' of coastal EbA potential for further, national and local analyses to quantify risk reduction and, thereby, guide investment in coastal ecosystems to help people adapt to climate change. In doing so, it underscores the global role that conserving and restoring ecosystems can play in protecting human lives and livelihoods, as well as biodiversity, in the face of climate change. more...

Seabirds are globally threatened. In the face of multiple threats, it is critical to understand how conservation strategies that mitigate one threat intersect with others to impact population viability. Marine threats, including pollution, climate change, and fisheries could derail gains to seabird populations resulting from arduous predator eradication efforts. However, this potentially negative effect is yet to be evaluated. We test whether mortality from marine threats can subvert the on-going recovery of 17 seabird species from 37 colonies on islands worldwide where predators were removed. We use demographic modelling to estimate potential adult mortality from fisheries, plastic ingestion, and climate change. For 82% of the species we examine, marine threats do not impede recovery following predator eradication. However, for six colonies of three species, Calonectris diomedea, C. borealis, and Ardenna carneipes, mortality from multiple marine threats may interrupt their recovery. Combining our demographic approach with comparative phylogenetic methods, we explore whether foraging niche, range, and morphometric traits inform the vulnerability to marine threats using an expanded dataset of 81 seabird species. Our analyses reveal surface filtering and pursuit diving species, and species with smaller at-sea distributions to be most vulnerable to declines due to multiple threats. However, these traits do not necessarily predict species’ vulnerability to marine threats in the absence of predators at nesting colonies, suggesting that shared traits may not be useful to infer vulnerability to multiple marine threats. Post-eradication monitoring to determine whether species require additional conservation management following predator eradication are essential in the face of intensifying pressures in the marine environment. more...

Humans have elevated global extinction rates and thus lowered global scale species richness. However, there is no a priori reason to expect that losses of global species richness should always, or even often, trickle down to losses of species richness at regional and local scales, even though this relationship is often assumed. Here, we show that scale can modulate our estimates of species richness change through time in the face of anthropogenic pressures, but not in a unidirectional way. Instead, the magnitude of species richness change through time can increase, decrease, reverse, or be unimodal across spatial scales. Using several case studies, we show different forms of scale‐dependent richness change through time in the face of anthropogenic pressures. For example, Central American corals show a homogenization pattern, where small scale richness is largely unchanged through time, while larger scale richness change is highly negative. Alternatively, birds in North America showed a differentiation effect, where species richness was again largely unchanged through time at small scales, but was more positive at larger scales. Finally, we collated data from a heterogeneous set of studies of different taxa measured through time from sites ranging from small plots to entire continents, and found highly variable patterns that nevertheless imply complex scale‐dependence in several taxa. In summary, understanding how biodiversity is changing in the Anthropocene requires an explicit recognition of the influence of spatial scale, and we conclude with some recommendations for how to better incorporate scale into our estimates of change. Postprint more...

Seabirds are among the most threatened groups of birds, and predation by invasive mammals is one of the most acute threats at their island breeding stations. Island restoration projects increasingly involve the eradication of invasive non-native mammals, with benefits for seabirds and other island fauna. To date, demonstrated benefits of invasive mammal eradication include increased seabird nesting success and enhanced adult survival. However, the recovery dynamics of seabird populations have not been documented. Drawing on data from across the world, we assemble population growth rates (λ) of 181 seabird populations of 69 species following successful eradication projects. After successful eradication, the median growth rate was 1.119 and populations with positive growth (λ > 1; n = 151) greatly outnumbered those in decline (λ more...

Summary Ecological and evolutionary research increasingly uses quantitative synthesis of primary research studies (meta-analysis) for answering fundamental questions, informing environmental policy and summarizing results for decision makers. Knowing how meta-analysis works is important for researchers so that their research can have broader impact. Meta-analytic thinking encourages scientists to see single primary research studies as substantial contributions to a larger picture. To facilitate inclusion in a meta-analysis, relevant primary research studies must be found and basic information about the methods and results must be thoroughly, clearly and transparently reported. While many published papers provide this information, it is common for essential data to be omitted, leading to study exclusion from meta-analyses. We provide guidelines for correctly reporting basic data needed from primary studies in ecology and evolutionary biology so that they can be included in meta-analyses, together with examples that show how data should be reported to enable calculation and analysis of effect sizes, and how data should be made accessible. These guidelines are important for reporting research results in general, whether or not results are included in subsequent meta-analyses, because they are necessary for the interpretation and assessment of study outcomes. Increased implementation of these guidelines by authors, editors and publishers, and reinforcement by funders, will foster higher quality and more inclusive syntheses, further the goals of transparency and reproducibility in science, and improve the quality and value of primary research studies. more...

Double-crested cormorants (Phalacrocorax auritus) have long and often been implicated in having detrimental effects on fisheries. Research has shown that the main components of cormorant diets vary significantly among forage, invasive, or economically important fish species. This study builds on previous work in the north basin of Lake Michigan by focusing on cormorant diet composition at their only significant nesting colony in the southern basin at East Chicago, Indiana where cormorant diet has been unstudied. Regurgitated pellets were collected from the colony and diagnostic bones were used to elucidate diet composition. Alewife (Alosa pseudoharengus), round goby (Neogobius melanostomus), Lepomis spp., white perch (Morone americana) and yellow perch (Perca flavescens) were the most frequently found prey items depending on cormorant feeding period. Invasive species, most notably alewife, round goby, and white perch, contributed over 80% and 90% of the diet of cormorants by biomass and number, respectively. No salmonine species were detected suggesting that negative effects on this important fishery would likely occur only via direct competition for prey (e.g., alewife). Predation on yellow perch, which occurred mainly prior to and during the perch spawning season (i.e., of age-1 and older individuals), may warrant further study to quantify the effects on the local yellow perch population. However, because yellow perch abundance is thought to be currently limited by poor recruitment at age-0, these results do not support the active management of the cormorants at this colony to protect or recover local fisheries. more...