Meta-Ecosystems 2.0: Rooting the Theory into the Field

Invasive species drive cross-ecosystem effects worldwide

Invasive species are pervasive around the world and have profound impacts on the ecosystem they invade. Invasive species, however, can also have impacts beyond the ecosystem they invade by altering the flow of non-living materials (for example, nutrients or chemicals) or movement of organisms across the boundaries of the invaded ecosystem. Cross-ecosystem interactions via spatial flows are ubiquitous in nature, for example, connecting forests and lakes, grasslands and rivers, and coral reefs and the deep ocean. Yet, we have a limited understanding of the cross-ecosystem impacts invasive species have relative to their local effects. By synthesizing emerging evidence, here we demonstrate the cross-ecosystem impacts of invasive species as a ubiquitous phenomenon that influences biodiversity and ecosystem functioning around the world. We identify three primary ways by which invasive species have cross-ecosystem effects: first, by altering the magnitude of spatial flows across ecosystem boundaries; second, by altering the quality of spatial flows; and third, by introducing novel spatial flows. Ultimately, the strong impacts invasive species can drive across ecosystem boundaries suggests the need for a paradigm shift in how we study and manage invasive species around the world, expanding from a local to a cross-ecosystem perspective.

Aquatic connectivity: challenges and solutions in a changing climate

The challenge of managing aquatic connectivity in a changing climate is exacerbated in the presence of additional anthropogenic stressors, social factors, and economic drivers. Here we discuss these issues in the context of structural and functional connectivity for aquatic biodiversity, specifically fish, in both the freshwater and marine realms. We posit that adaptive management strategies that consider shifting baselines and the socio-ecological implications of climate change will be required to achieve management objectives. The role of renewable energy expansion, particularly hydropower, is critically examined for its impact on connectivity. We advocate for strategic spatial planning that incorporates nature-positive solutions, ensuring climate mitigation efforts are harmonized with biodiversity conservation. We underscore the urgency of integrating robust scientific modelling with stakeholder values to define clear, adaptive management objectives. Finally, we call for innovative monitoring and predictive decision-making tools to navigate the uncertainties inherent in a changing climate, with the goal of ensuring the resilience and sustainability of aquatic ecosystems.

Vicuña antipredator diel movement drives spatial nutrient subsidies in a high Andean ecosystem

Large animals could be important drivers of spatial nutrient subsidies when they ingest resources in some habitats and release them in others, even moving nutrients against elevational gradients. In high Andean deserts, vicuñas (Vicugna vicugna) move daily between nutrient-rich wet meadows, where there is abundant water and forage but high risk of predation by pumas (Puma concolor), and nutrient-poor open plains with lower risk of predation. In all habitats, vicuñas defecate and urinate in communal latrines. We investigated how these latrines impacted soil and plant nutrient concentrations across three habitats in the Andean ecosystem (meadows, plains, and canyons) and used stable isotope analysis to explore the source of fecal nutrients in latrines. Latrine soils had higher concentrations of nitrogen, carbon, and other nutrients than did nonlatrine soils across all habitats. These inputs corresponded with an increase in plant quality (lower C:N) at latrine sites in plains and canyons, but not in meadows. Stable isotope mixing models suggest that ~7% of nutrients in plains latrines originated from vegetation in meadows, which is disproportionately higher than the relative proportion of meadow habitat (2.6%) in the study area. In contrast, ~68% of nutrients in meadow latrines appear to originate from plains and canyon vegetation, though these habitats made up nearly 98% of the study area. Vicuña diel movements thus appear to concentrate nutrients in latrines within habitats and to drive cross-habitat nutrient subsidies, with disproportionate transport from low-lying, nutrient-rich meadows to more elevated, nutrient-poor plains. When these results are scaled up to the landscape scale, the amount of nitrogen and phosphorus subsidized in soil at plains latrines was of the same order of magnitude as estimates of annual atmospheric nitrogen and phosphorus deposition for this region (albeit far more localized and patchy). Thus, vicuña-mediated nutrient redistribution and deposition appears to be an important process impacting ecosystem functioning in arid Andean environments, on par with other major inputs of nutrients to the system.

Landscape use by large grazers in a grassland is restructured by wildfire

Animals navigate landscapes based on perceived risks vs. rewards, as inferred from features of the landscape. In the wild, knowing how strongly animal movement is directed by landscape features is difficult to ascertain but widespread disturbances such as wildfires can serve as natural experiments. We tested the hypothesis that wildfires homogenize the risk/reward landscape, causing movement to become less directed, given that fires reduce landscape complexity as habitat structures (e.g., tree cover, dense brush) are burned. We used satellite imagery of a research reserve in Northern California to count and categorize paths made primarily by mule deer (Odocoileus hemionus) in grasslands. Specifically, we compared pre-wildfire (August 2014) and post-wildfire (September 2018) image history layers among locations that were or were not impacted by wildfire (i.e., a Before/After Control/Impact design). Wildfire significantly altered spatial patterns of deer movement: more new paths were gained and more old paths were lost in areas of the reserve that were impacted by wildfire; movement patterns became less directed in response to fire, suggesting that the risk/reward landscape became more homogenous, as hypothesized. We found evidence to suggest that wildfire affects deer populations at spatial scales beyond their scale of direct impact and raises the interesting possibility that deer perceive risks and rewards at different spatial scales. In conclusion, our study provides an example of how animals integrate spatial information from the environment to make movement decisions, setting the stage for future work on the broader ecological implications for populations, communities, and ecosystems, an emerging interest in ecology.

Nutrients from spawning salmon influence leaf area, tissue density, and nitrogen-15 in riparian plant leaves

Nutrient subsidies have significant impacts on ecosystems by connecting disjunct habitats, often through long-distance animal migrations. Salmon migrations on the North Pacific coasts provide these kinds of nutrient subsidies from senescent fish at the end of their life cycle, which can have significant ecological effects on terrestrial species. This can include impacts on individuals, populations, and communities, where shifts in community composition towards plant species that indicate nitrogen-rich soils have been documented. We investigated the effects of variation in salmon spawning density on the leaf traits of four common riparian plant species on the central coast of British Columbia, Canada. We found that all plant species had higher foliar salmon-derived nitrogen on streams with a higher spawning density. Three of the four species had larger leaves, and one species also had higher leaf mass per area on streams with more salmon. However, we found no differences in leaf greenness or foliar percent nitrogen among our study streams. These results demonstrate that nutrient subsidies from spawning salmon can have significant impacts on the ecology, morphology, and physiology of riparian plants, which lends support to a mechanism by which certain plants are more common on productive salmon streams.

Environmental DNA and remote sensing datasets reveal the spatial distribution of aquatic insects in a disturbed subtropical river system

Biodiversity datasets with high spatial resolution are critical prerequisites for river protection and management decision-making. However, traditional morphological biomonitoring is inefficient and only provides several site estimates, and there is an urgent need for new approaches to predict biodiversity on fine spatial scales throughout the entire river systems. Here, we combined the environmental DNA (eDNA) and remote sensing (RS) technologies to develop a novel approach for predicting the spatial distribution of aquatic insects with high spatial resolution in a disturbed subtropical Dongjiang River system of southeast China. First, we screened thirteen RS-based vegetation indices that significantly correlated with the eDNA-inferred richness of aquatic insects. In particular, the green normalized difference vegetation index (GNDVI) and normalized difference red-edge2 (NDRE2) were closely related to eDNA-inferred richness. Second, using the gradient boosting decision tree, our data showed that the spatial pattern of eDNA-inferred richness could achieve a high spatial resolution to 500 m reach and accurate prediction of more than 80%, and the prediction efficiency of the headwater streams (Strahler stream order = 1) was slightly higher than the downstream (Strahler stream order >1). Third, using the random forest algorithm, the spatial distribution of aquatic insects could reach a prediction rate of over 70% for the presence or absence of specific genera. Overall, this study provides a new approach to achieving high spatial resolution prediction of the distribution of aquatic insects, which supports decision-making on river diversity protection under climate changes and human impacts.

Integrating monthly spring tidal waves into estuarine carbon budget of meta-ecosystems

The contribution of lateral carbon (C) to hydrological processes is well known for its ecological functions in the estuarine C budget across the terrestrial-aquatic interfaces. However, sampling of individual daily tides during multiple months or seasons in heterogeneous patches of landscape makes extrapolation from days to months or seasons challenging. In this paper, we examine the terrestrial-aquatic lateral hydrological C flux for an estuarine marsh where monthly tides, including consecutive daily spring tides, were measured over the course of an entire year. We found a significant correlation between imported and exported hydrological dissolved C, both dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC), although a similar correlation was not found for particulate organic carbon (POC). Based on a total of 44 sampling trips over a year, this saltmarsh appeared to be a net exporter of DOC and DIC but a net sink of POC. Furthermore, the lateral hydrological C budget functioned as a limited lateral C sink in terms of organic C (i.e., ΔPOC and ΔDOC), while the marsh functioned as a small lateral C source. Our findings highlight the importance of lateral hydrologic inflows/outflows in wetland C budgets of land-water interfaces, especially in those characterized by the meta-ecosystem framework. Surprisingly, different C species responded unequally to the lateral hydrological C budget, suggesting that a conceptual realization of meta-ecosystem is a powerful theoretical framework to extend the outwelling hypothesis.

Grassland intensification effects cascade to alter multifunctionality of wetlands within metaecosystems

Sustainable agricultural intensification could improve ecosystem service multifunctionality, yet empirical evidence remains tenuous, especially regarding consequences for spatially coupled ecosystems connected by flows across ecosystem boundaries (i.e., metaecosystems). Here we aim to understand the effects of land-use intensification on multiple ecosystem services of spatially connected grasslands and wetlands, where management practices were applied to grasslands but not directly imposed to wetlands. We synthesize long-term datasets encompassing 53 physical, chemical, and biological indicators, comprising >11,000 field measurements. Our results reveal that intensification promotes high-quality forage and livestock production in both grasslands and wetlands, but at the expense of water quality regulation, methane mitigation, non-native species invasion resistance, and biodiversity. Land-use intensification weakens relationships among ecosystem services. The effects on grasslands cascade to alter multifunctionality of embedded natural wetlands within the metaecosystems to a similar extent. These results highlight the importance of considering spatial flows of resources and organisms when studying land-use intensification effects on metaecosystems as well as when designing grassland and wetland management practices to improve landscape multifunctionality.

The effects of longitudinal fragmentation on riverine beta diversity are modulated by fragmentation intensity

The loss of longitudinal connectivity affects river systems globally, being one of the leading causes of the freshwater biodiversity crisis. Barriers alter the dispersal of aquatic organisms and limit the exchange of species between local communities, disrupting metacommunity dynamics. However, the interplay between connectivity losses due to dams and other drivers of metacommunity structure, such as the configuration of the river network, needs to be explored. In this paper, we analyzed the response of fish communities to the network position and the fragmentation induced by dams while controlling for human pressures and environmental gradients. We studied three large European catchments covering a fragmentation gradient: Upper Danube (Austrian section), Ebro (Spain), and Odra/Oder (Poland). We quantified fragmentation through reach-scaled connectivity indices that account for the position of barriers along the dendritic network and the dispersal capacity of the organisms. We used generalized linear models to explain species richness and Local Contributions to Beta Diversity (LCBD) and multilinear regressions on the distance matrix to describe Beta Diversity and its Replacement and Richness Difference components. Results show that species richness was not affected by fragmentation. Network centrality metrics were relevant drivers of beta diversity for catchments with lower fragmentation (Ebro, Odra), and fragmentation indices were strong beta diversity predictors for the catchment with higher fragmentation (Danube). We conclude that in highly fragmented catchments, the effects of network centrality/isolation on biodiversity could be masked by the effects of dam fragmentation. In such catchments, metapopulation and metacommunity dynamics can be strongly altered by barriers, and the restoration of longitudinal connectivity (i.e. the natural centrality/isolation gradient) is urgent to prevent local extinctions.

Non-perennial segments in river networks

Non-perennial river segments - those that recurrently cease to flow or frequently dry - occur in all river networks and are globally more abundant than perennial (always flowing) segments. However, research and management have historically focused on perennial river segments. In this Review, we outline how non-perennial segments are integral parts of river networks. Repeated cycles of flowing, non-flowing and dry phases in non-perennial segments influence biodiversity and ecosystem dynamics at different spatial scales, from individual segments to entire river networks. Varying configurations of perennial and non-perennial segments govern physical, chemical and ecological responses to changes in the flow regimes of each river network, especially in response to human activities. The extent of non-perennial segments in river networks has increased owing to warming, changing hydrological patterns and human activities, and this increase is predicted to continue. Moreover, the dry phases of flow regimes are expected to be longer, drier and more frequent, albeit with high regional variability. These changes will likely impact biodiversity, potentially tipping some ecosystems to compromised stable states. Effective river-network management must recognize ecosystem services (such as flood risk management and groundwater recharge) provided by non-perennial segments and ensure their legislative and regulatory protection, which is often lacking.

Impacts of habitat connectivity on grassland arthropod metacommunity structure: A field-based experimental test of theory

Metacommunity theory has advanced scientific understanding of how species interactions and spatial processes influence patterns of biodiversity and community structure across landscapes. While the central tenets of metacommunity theory have been promoted as pivotal considerations for conservation management, few field experiments have tested the validity of metacommunity predictions. Here, we tested one key prediction of metacommunity theory-that decreasing habitat connectivity should erode metacommunity structure by hindering species movement between patches. For 2 years, we manipulated an experimental old-field grassland ecosystem via mowing to represent four levels of habitat connectivity: (1) open control, (2) full connectivity, (3) partial connectivity, and (4) no connectivity. Within each treatment plot (10 × 10 m, n = 4 replicates), we measured the abundance and diversity (i.e., alpha and beta) of both flying and ground arthropods using sticky and pitfall traps, respectively. We found that the abundance and diversity of highly mobile flying arthropods were unaffected by habitat connectivity, whereas less mobile ground arthropods were highly impacted. The mean total abundance of ground arthropods was 2.5× and 2× higher in the control and partially connected plots compared to isolated patches, respectively. We also reveal that habitat connectivity affected the trophic interactions of ground arthropods, with predators (e.g., wolf spiders, ground spiders) being highly positively correlated with micro-detritivores (springtails, mites) but not macro-detritivores (millipedes, isopods) as habitat connectivity increased. Together these findings indicate that changes in habitat connectivity can alter the metacommunity structure for less mobile organisms such as ground arthropods. Because of their essential roles in terrestrial ecosystem functioning and services, we recommend that conservationists, restoration practitioners, and land managers include principles of habitat connectivity for ground arthropods when designing biodiversity management programs.

Animal and plant space-use drive plant diversity-productivity relationships

Plant community productivity generally increases with biodiversity, but the strength of this relationship exhibits strong empirical variation. In meta-food-web simulations, we addressed if the spatial overlap in plants' resource access and animal space-use can explain such variability. We found that spatial overlap of plant resource access is a prerequisite for positive diversity-productivity relationships, but causes exploitative competition that can lead to competitive exclusion. Space-use of herbivores causes apparent competition among plants, resulting in negative relationships. However, space-use of larger top predators integrates sub-food webs composed of smaller species, offsetting the negative effects of exploitative and apparent competition and leading to strongly positive diversity-productivity relationships. Overall, our results show that spatial overlap of plants' resource access and animal space-use can greatly alter the strength and sign of such relationships. In particular, the scaling of animal space-use effects opens new perspectives for linking landscape processes without effects on biodiversity to productivity patterns.

Quality matters: Stoichiometry of resources modulates spatial feedbacks in aquatic-terrestrial meta-ecosystems

Species dispersal and resource spatial flows greatly affect the dynamics of connected ecosystems. So far, research on meta-ecosystems has mainly focused on the quantitative effect of subsidy flows. Yet, resource exchanges at heterotrophic-autotrophic (e.g. aquatic-terrestrial) ecotones display a stoichiometric asymmetry that likely matters for functioning. Here, we joined ecological stoichiometry and the meta-ecosystem framework to understand how subsidy stoichiometry mediates the response of the meta-ecosystem to subsidy flows. Our model results demonstrate that resource flows between ecosystems can induce a positive spatial feedback loop, leading to higher production at the meta-ecosystem scale by relaxing local ecosystem limitations ('spatial complementarity'). Furthermore, we show that spatial flows can also have an unexpected negative impact on production when accentuating the stoichiometric mismatch between local resources and basal species needs. This study paves the way for studies on the interdependency of ecosystems at the landscape extent.

Connecting distinct realms along multiple dimensions: A meta-ecosystem resilience perspective

Resilience research is central to confront the sustainability challenges to ecosystems and human societies in a rapidly changing world. Given that social-ecological problems span the entire Earth system, there is a critical need for resilience models that account for the connectivity across intricately linked ecosystems (i.e., freshwater, marine, terrestrial, atmosphere). We present a resilience perspective of meta-ecosystems that are connected through the flow of biota, matter and energy within and across aquatic and terrestrial realms, and the atmosphere. We demonstrate ecological resilience sensu Holling using aquatic-terrestrial linkages and riparian ecosystems more generally. A discussion of applications in riparian ecology and meta-ecosystem research (e.g., resilience quantification, panarchy, meta-ecosystem boundary delineations, spatial regime migration, including early warning indications) concludes the paper. Understanding meta-ecosystem resilience may have potential to support decision making for natural resource management (scenario planning, risk and vulnerability assessments).

Eco-evolution from deep time to contemporary dynamics: The role of timescales and rate modulators

Eco-evolutionary dynamics, or eco-evolution for short, are often thought to involve rapid demography (ecology) and equally rapid heritable phenotypic changes (evolution) leading to novel, emergent system behaviours. We argue that this focus on contemporary dynamics is too narrow: Eco-evolution should be extended, first, beyond pure demography to include all environmental dimensions and, second, to include slow eco-evolution which unfolds over thousands or millions of years. This extension allows us to conceptualise biological systems as occupying a two-dimensional time space along axes that capture the speed of ecology and evolution. Using Hutchinson's analogy: Time is the 'theatre' in which ecology and evolution are two interacting 'players'. Eco-evolutionary systems are therefore dynamic: We identify modulators of ecological and evolutionary rates, like temperature or sensitivity to mutation, which can change the speed of ecology and evolution, and hence impact eco-evolution. Environmental change may synchronise the speed of ecology and evolution via these rate modulators, increasing the occurrence of eco-evolution and emergent system behaviours. This represents substantial challenges for prediction, especially in the context of global change. Our perspective attempts to integrate ecology and evolution across disciplines, from gene-regulatory networks to geomorphology and across timescales, from today to deep time.

A spatial fingerprint of land-water linkage of biodiversity uncovered by remote sensing and environmental DNA

Aquatic and terrestrial ecosystems are tightly connected via spatial flows of organisms and resources. Such land-water linkages integrate biodiversity across ecosystems and suggest a spatial association of aquatic and terrestrial biodiversity. However, knowledge about the extent of this spatial association is limited. By combining satellite remote sensing (RS) and environmental DNA (eDNA) extraction from river water across a 740-km² mountainous catchment, we identify a characteristic spatial land-water fingerprint. Specifically, we find a spatial association of riverine eDNA diversity with RS spectral diversity of terrestrial ecosystems upstream, peaking at a 400 m distance yet still detectable up to a 2.0 km radius. Our findings show that biodiversity patterns in rivers can be linked to the functional diversity of surrounding terrestrial ecosystems and provide a dominant scale at which these linkages are strongest. Such spatially explicit information is necessary for a functional understanding of land-water linkages.

Resident-Disperser Differences and Genetic Variability Affect Communities in Microcosms

AbstractDispersal is a key process mediating ecological and evolutionary dynamics. Its effects on the dynamics of spatially structured systems, population genetics, and species range distribution can depend on phenotypic differences between dispersing and nondispersing individuals. However, scaling up the importance of resident-disperser differences to communities and ecosystems has rarely been considered, in spite of intraspecific phenotypic variability being an important factor mediating community structure and productivity. Here, we used the ciliate Tetrahymena thermophila, in which phenotypic traits are known to differ between residents and dispersers, to test (i) whether these resident-disperser differences affect biomass and composition in competitive communities composed of four other Tetrahymena species and (ii) whether these effects are genotype dependent. We found that dispersers led to a lower community biomass compared with residents. This effect was highly consistent across the 20 T. thermophila genotypes used, despite intraspecific variability in resident-disperser phenotypic differences. We also found a significant genotypic effect on biomass production, showing that intraspecific variability has consequences for communities. Our study suggests that individual dispersal strategy can scale up to community productivity in a predictable way, opening new perspectives to the functioning of spatially structured ecosystems.

Linking human impacts to community processes in terrestrial and freshwater ecosystems

Human impacts such as habitat loss, climate change and biological invasions are radically altering biodiversity, with greater effects projected into the future. Evidence suggests human impacts may differ substantially between terrestrial and freshwater ecosystems, but the reasons for these differences are poorly understood. We propose an integrative approach to explain these differences by linking impacts to four fundamental processes that structure communities: dispersal, speciation, species-level selection and ecological drift. Our goal is to provide process-based insights into why human impacts, and responses to impacts, may differ across ecosystem types using a mechanistic, eco-evolutionary comparative framework. To enable these insights, we review and synthesise (i) how the four processes influence diversity and dynamics in terrestrial versus freshwater communities, specifically whether the relative importance of each process differs among ecosystems, and (ii) the pathways by which human impacts can produce divergent responses across ecosystems, due to differences in the strength of processes among ecosystems we identify. Finally, we highlight research gaps and next steps, and discuss how this approach can provide new insights for conservation. By focusing on the processes that shape diversity in communities, we aim to mechanistically link human impacts to ongoing and future changes in ecosystems.

Scaling migrations to communities: An empirical case of migration network in the Arctic

Seasonal migrants transport energy, nutrients, contaminants, parasites and diseases, while also connecting distant food webs between communities and ecosystems, which contributes to structuring meta-communities and meta-ecosystems. However, we currently lack a framework to characterize the structure of the spatial connections maintained by all migratory species reproducing or wintering in a given community. Here, we use a network approach to represent and characterize migratory pathways at the community level and provide an empirical description of this pattern from a High-Arctic terrestrial community. We define community migration networks as multipartite networks representing different biogeographic regions connected with a focal community through the seasonal movements of its migratory species. We focus on the Bylot Island High-Arctic terrestrial community, a summer breeding ground for several migratory species. We define the non-breeding range of each species using tracking devices, or range maps refined by flyways and habitat types. We show that the migratory species breeding on Bylot Island are found across hundreds of ecoregions on several continents during the non-breeding period and present a low spatial overlap. The migratory species are divided into groups associated with different sets of ecoregions. The non-random structure observed in our empirical community migration network suggests evolutionary and geographic constraints as well as ecological factors act to shape migrations at the community level. Overall, our study provides a simple and generalizable framework as a starting point to better integrate migrations at the community level. Our framework is a far-reaching tool that could be adapted to address the seasonal transport of energy, contaminants, parasites and diseases in ecosystems, as well as trophic interactions in communities with migratory species.

The significance of partial migration for food web and ecosystem dynamics

Migration is ubiquitous and can strongly shape food webs and ecosystems. Less familiar, however, is that the majority of life cycle, seasonal and diel migrations in nature are partial migrations: only a fraction of the population migrates while the other individuals remain in their resident ecosystem. Here, we demonstrate different impacts of partial migration rendering it fundamental to our understanding of the significance of migration for food web and ecosystem dynamics. First, partial migration affects the spatiotemporal distribution of individuals and the food web and ecosystem-level processes they drive differently than expected under full migration. Second, whether an individual migrates or not is regularly correlated with morphological, physiological, and/or behavioural traits that shape its food-web and ecosystem-level impacts. Third, food web and ecosystem dynamics can drive the fraction of the population migrating, enabling the potential for feedbacks between the causes and consequences of migration within and across ecosystems. These impacts, individually and in combination, can yield unintuitive effects of migration and drive the dynamics, diversity and functions of ecosystems. By presenting the first full integration of partial migration and trophic (meta-)community and (meta-)ecosystem ecology, we provide a roadmap for studying how migration affects and is affected by ecosystem dynamics in a changing world.

Experimental addition of marine-derived nutrients affects wildflower traits in a coastal meta-ecosystem

Organismal movement can bring individuals, resources and novel interactions across ecosystem boundaries and into recipient habitats, thereby forming meta-ecosystems. For example, Pacific salmon ecosystems receive large marine-derived nitrogen subsidies during annual spawning events, which can have a wide range of effects on aquatic and terrestrial plant species and communities. In this study, we evaluate the effects of cross-ecosystem nutrient subsidies on terrestrial plant growth and reproduction. We conducted a large-scale field experiment with four treatments: (i) addition of a pink salmon (Oncorhynchus gorbuscha) carcass, (ii) addition of the drift seaweed rockweed (Fucus distichus), (iii) addition of both salmon + rockweed, and (iv) a control. We examined treatment effects on leaf nitrogen and fitness-associated floral traits in four common estuarine wildflower species. We found elevated leaf ∂¹⁵N in all plant species and all sampling years in treatments with salmon carcass additions but did not observe any differences in leaf per cent nitrogen. We also observed larger leaf area in two species, a context-dependent increase in floral display area in two species, and a limited increase in plant seed set in response to both salmon carcass treatments. In sum, our study suggests that marine nutrients can affect terrestrial plant growth and reproduction.

Three perspectives on the prediction of chemical effects in ecosystems

The increasing production, use and emission of synthetic chemicals into the environment represents a major driver of global change. The large number of synthetic chemicals, limited knowledge on exposure patterns and effects in organisms and their interaction with other global change drivers hamper the prediction of effects in ecosystems. However, recent advances in biomolecular and computational methods are promising to improve our capacity for prediction. We delineate three idealised perspectives for the prediction of chemical effects: the suborganismal, organismal and ecological perspective, which are currently largely separated. Each of the outlined perspectives includes essential and complementary theories and tools for prediction but captures only part of the phenomenon of chemical effects. Links between the perspectives may foster predictive modelling of chemical effects in ecosystems and extrapolation between species. A major challenge for the linkage is the lack of data sets simultaneously covering different levels of biological organisation (here referred to as biological levels) as well as varying temporal and spatial scales. Synthesising the three perspectives, some central aspects and associated types of data seem particularly necessary to improve prediction. First, suborganism- and organism-level responses to chemicals need to be recorded and tested for relationships with chemical groups and organism traits. Second, metrics that are measurable at many biological levels, such as energy, need to be scrutinised for their potential to integrate across levels. Third, experimental data on the simultaneous response over multiple biological levels and spatiotemporal scales are required. These could be collected in nested and interconnected micro- and mesocosm experiments. Lastly, prioritisation of processes involved in the prediction framework needs to find a balance between simplification and capturing the essential complexity of a system. For example, in some cases, eco-evolutionary dynamics and interactions may need stronger consideration. Prediction needs to move from a static to a real-world eco-evolutionary view.

Unifying approaches to Functional Marine Connectivity for improved marine resource management: the European SEA-UNICORN COST Action

Truly sustainable development in a human-altered, fragmented marine environment subject to unprecedented climate change, demands informed planning strategies in order to be successful. Beyond a simple understanding of the distribution of marine species, data describing how variations in spatio-temporal dynamics impact ecosystem functioning and the evolution of species are required. Marine Functional Connectivity (MFC) characterizes the flows of matter, genes and energy produced by organism movements and migrations across the seascape. As such, MFC determines the ecological and evolutionary interdependency of populations, and ultimately the fate of species and ecosystems. Gathering effective MFC knowledge can therefore improve predictions of the impacts of environmental change and help to refine management and conservation strategies for the seas and oceans. Gathering these data are challenging however, as access to, and survey of marine ecosystems still presents significant challenge. Over 50 European institutions currently investigate aspects of MFC using complementary methods across multiple research fields, to understand the ecology and evolution of marine species. The aim of SEA-UNICORN, a COST Action supported by COST (European Cooperation in Science and Technology), is to bring together this research effort, unite the multiple approaches to MFC, and to integrate these under a common conceptual and analytical framework. The consortium brings together a diverse group of scientists to collate existing MFC data, to identify knowledge gaps, to enhance complementarity among disciplines, and to devise common approaches to MFC. SEA-UNICORN will promote co-working between connectivity practitioners and ecosystem modelers to facilitate the incorporation of MFC data into the predictive models used to identify marine conservation priorities. Ultimately, SEA-UNICORN will forge strong forward-working links between scientists, policy-makers and stakeholders to facilitate the integration of MFC knowledge into decision support tools for marine management and environmental policies.

Bird Beta Diversity in Sharp Contrasting Altai Landscapes: Locality Connectivity Is the Influential Factor on Community Composition

Simple Summary

Understanding the ecological processes involved in establishing a metacommunity, a collection of small communities linked by species dispersal, could help with biodiversity conservation. In this work, we examine how local community connectivity affects the distributional patterns of various bird species across metacommunities in the strikingly different Altai landscapes. We discovered that connectivity was most important for determining community composition in metacommunities. High beta diversity and a high turnover component in the research region showed that regional-scale conservation efforts should consider overall biodiversity. Although they are not part of the Altai-Sayan biodiversity ecoregion, the riparian and desert landscapes are essential to the birds that reside in the mountain ranges and should be regarded as integral parts of the ecoregion, and high connectivity stepping-stone habitats in these landscapes should be protected.

Abstract

Located on the southwest slope and plain areas of the Altai Mountains in China, this study aims to explore bird composition variation (beta diversity) in mountain landscape (metacommunity M), riparian landscape (metacommunity R), desert landscape (metacommunity D) and across the three landscapes (metacommunity A), and to assess how patch connectivity with environmental and spatial factors influence species distributional patterns across multiple metacommunities. In 78 transect lines over the study area, 9724 detections of 139 bird species were detected. We calculated the beta diversity, its turnover and nestedness components in four metacommunities. We used the variation partitioning method to investigate the relative importance between the environment, spatial variation and locality connectivity in driving bird community composition variation. We found high beta diversities with a small contribution of nestedness components in all four metacommunities. When only a single set of predictors is contained in the model, the predictor that best explains the variation of bird community composition is connectivity in metacommunity M, R and D and spatial predictor in metacommunity A. In all three sets of predictors, 73.8~85.4% of variations of community composition can be explained in the four metacommunities, and connectivity always contributed the most. High beta diversity and a high turnover component imply that regional-scale conservation efforts should be thought of as preserving overall biodiversity. A conservation strategy is to keep stepping-stone habitats with good connectivity in the middle of the riparian landscape. Along with the Altai-Sayan biodiversity ecoregion, the desert and riparian environments are essential for birds residing in the mountainous terrain. Furthermore, they should be regarded as integral parts of the ecoregion.

Scaling up our understanding of tipping points

Anthropogenic activities are increasingly affecting ecosystems across the globe. Meanwhile, empirical and theoretical evidence suggest that natural systems can exhibit abrupt collapses in response to incremental increases in the stressors, sometimes with dramatic ecological and economic consequences. These catastrophic shifts are faster and larger than expected from the changes in the stressors and happen once a tipping point is crossed. The primary mechanisms that drive ecosystem responses to perturbations lie in their architecture of relationships, i.e. how species interact with each other and with the physical environment and the spatial structure of the environment. Nonetheless, existing theoretical work on catastrophic shifts has so far largely focused on relatively simple systems that have either few species and/or no spatial structure. This work has laid a critical foundation for understanding how abrupt responses to incremental stressors are possible, but it remains difficult to predict (let alone manage) where or when they are most likely to occur in more complex real-world settings. Here, we discuss how scaling up our investigations of catastrophic shifts from simple to more complex-species rich and spatially structured-systems could contribute to expanding our understanding of how nature works and improve our ability to anticipate the effects of global change on ecological systems. This article is part of the theme issue 'Ecological complexity and the biosphere: the next 30 years'.

Synchrony and Stability in Trophic Metacommunities: When Top Predators Navigate in a Heterogeneous World

Ecosystem stability strongly depends on spatial aspects since localized perturbations spread across an entire region through species dispersal. Assessing the synchrony of the response of connected populations is fundamental to understand stability at different scales because if populations fluctuate asynchronously, the risk of their simultaneous extinction is low, thus reducing the species' regional extinction risk. Here, we consider a metacommunity model consisting of two food chains connected by dispersal and we review the various mechanisms governing the transmission of small perturbations affecting populations in the vicinity of equilibrium. First, we describe how perturbations propagate vertically (i.e., within food chains through trophic interactions) and horizontally (i.e., between food chains through dispersal) in metacommunities. Then, we discuss the mechanisms susceptible to alter synchrony patterns such as density-depend dispersal or spatial heterogeneity. Density-dependent dispersal, which is the influence of prey or predator abundance on dispersal, has a major impact because the species with the highest coefficient of variation of biomass governs the dispersal rate of the dispersing species and determines the synchrony of its populations, thus bypassing the classic vertical transmission of perturbations. Spatial heterogeneity, which is a disparity between patches of the attack rate of predators on prey in our model, alters the vertical transmission of perturbations in each patch, thus making synchrony dependent on which patch is perturbed. Finally, by combining our understanding of the impact of each of these mechanisms on synchrony, we are able to full explain the response of realistic metacommunities such as the model developed by Rooney et al. (2006). By disentangling the main mechanisms governing synchrony, our metacommunity model provides a broad insight into the consequences of spacial aspects on food web stability.

From Forest Dynamics to Wetland Siltation in Mountainous Landscapes: A RS-Based Framework for Enhancing Erosion Control

Human activities have caused a significant change in the function and services that ecosystems have provided to society since historical times. In mountainous landscapes, the regulation of services such as water quality or erosion control has been impacted by land use and land cover (LULC) changes, especially the loss and fragmentation of forest patches. In this work, we develop a Remote Sensing (RS)-based modelling approach to identify areas for the implementation of nature-based solutions (NBS) (i.e., natural forest conservation and restoration) that allow reducing the vulnerability of aquatic ecosystems to siltation in mountainous regions. We used time series Landsat 5TM, 7ETM+, 8OLI and Sentinel 2A/2B MSI (S2) imagery to map forest dynamics and wetland distribution in Picos de Europa National Park (Cantabrian Mountains, northern Spain). We fed RS-based models with detailed in situ information based on photo-interpretation and fieldwork completed from 2017 to 2021. We estimated a forest cover increase rate of 2 ha/year comparing current and past LULC maps against external validation data. We applied this forest gain to a scenario generator model to derive a 30-year future LULC map that defines the potential forest extent for the study area in 2049. We then modelled the distribution of wetlands to identify the areas with the greatest potential for moisture accumulation. We used an S2 mosaic and topography-derived data such as the slope and topographic wetness index (TWI), which indicate terrain water accumulation. Overall accuracy scores reached values of 86% for LULC classification and 61% for wetland mapping. At the same time, we obtained the potential erosion using the NetMap software to identify potential sediment production, transport and deposition areas. Finally, forest dynamics, wetland distribution and potential erosion were combined in a multi-criteria analysis aiming to reduce the amount of sediment reaching selected wetlands. We achieved this by identifying the most suitable locations for the conservation and restoration of natural forests on slopes and in riparian areas, which may reduce the risk of soil erosion and maximise sediment filtering, respectively. The results show a network pattern for forest management that would allow for controlling erosion effects across space and time at three levels: one, by reducing the load that originates upslope in the absence of forest cover; two, by intersecting runoff at watercourses related to sediment transport; and three, by a lack of former barriers, by trapping erosion near to the receiving wetland systems, main river axes and contributing streams. In conclusion, the proposed methodology, which could be transferred to other mountain regions, allows to optimise investment for erosion prevention and wetland conservation by using only very specific areas of the landscape for habitat management (e.g., for NBS implementation).

Unifying approaches to Functional Marine Connectivity for improved marine resource management: the European SEA-UNICORN COST Action

Truly sustainable development in a human-altered, fragmented marine environment subject to unprecedented climate change, demands informed planning strategies in order to be successful. Beyond a simple understanding of the distribution of marine species, data describing how variations in spatio-temporal dynamics impact ecosystem functioning and the evolution of species are required. Marine Functional Connectivity (MFC) characterizes the flows of matter, genes and energy produced by organism movements and migrations across the seascape. As such, MFC determines the ecological and evolutionary interdependency of populations, and ultimately the fate of species and ecosystems. Gathering effective MFC knowledge can therefore improve predictions of the impacts of environmental change and help to refine management and conservation strategies for the seas and oceans. Gathering these data are challenging however, as access to, and survey of marine ecosystems still presents significant challenge. Over 50 European institutions currently investigate aspects of MFC using complementary methods across multiple research fields, to understand the ecology and evolution of marine species. The aim of SEA-UNICORN, a COST Action within the European Union Horizon 2020 framework programme, is to bring together this research effort, unite the multiple approaches to MFC, and to integrate these under a common conceptual and analytical framework. The consortium brings together a diverse group of scientists to collate existing MFC data, to identify knowledge gaps, to enhance complementarity among disciplines, and to devise common approaches to MFC. SEA-UNICORN will promote co-working between connectivity practitioners and ecosystem modelers to facilitate the incorporation of MFC data into the predictive models used to identify marine conservation priorities. Ultimately, SEA-UNICORN will forge strong forward-working links between scientists, policy-makers and stakeholders to facilitate the integration of MFC knowledge into decision support tools for marine management and environmental policies.

Seasonal Variation in Terrestrial Invertebrate Subsidies to Tropical Streams and Implications for the Feeding Ecology of Hart’s Rivulus (Anablepsoides hartii)

Terrestrial invertebrates are important subsidies to fish diets, though their seasonal dynamics and importance to tropical stream consumers are particularly understudied. In this year-round study of terrestrial invertebrate input to two Trinidadian headwater streams with different forest canopy densities, we sought to (a) measure the mass and composition of terrestrial inputs with fall-in traps to evaluate the influences of seasonality, canopy cover, and rainfall intensity, and; (b) compare terrestrial and benthic prey importance to Anablepsoides hartii (Hart’s Rivulus), the dominant invertivorous fish in these streams, by concurrently measuring benthic and drifting invertebrate standing stocks and the volume and composition of invertebrates in Rivulus guts throughout the year. The biomass of terrestrial invertebrate fall-in was 53% higher in the wet versus dry season; in particular, ant input was 320% higher. Ant biomass fall-in also increased with the density of canopy cover among sampling locations within both streams. Greater precipitation correlated with increased ant inputs to the more open-canopied stream and increased inputs of winged insects in the more closed canopy stream. Concurrently, the biomass of benthic invertebrates was reduced by more than half in the wet season in both streams. We detected no differences in the total volume of terrestrial prey in Rivulus diets between seasons, though ants were a greater proportion of their diet in the wet season. In contrast, benthic prey were nearly absent from Rivulus diets in the wet season in both streams. We conclude that terrestrial invertebrates are a substantial year-round prey subsidy for invertivores in tropical stream ecosystems like those we studied, which may contrast to most temperate streams where such terrestrial inputs are significantly reduced in the cold season. Interestingly, the strongest seasonal pattern in these tropical streams was observed in benthic invertebrate biomass which was greatly reduced and almost absent from Rivulus diets during the wet season. This pattern is essentially the inverse of the pattern observed in many temperate streams and highlights the need for additional studies in tropical ecosystems to better understand how spatial and temporal variation in terrestrial subsidies and benthic prey populations combine to influence consumer diets and the structure of tropical stream food webs.

From meta-system theory to the sustainable management of rivers in the Anthropocene

Regional-scale ecological processes, such as the spatial flows of material, energy, and organisms, are fundamental for maintaining biodiversity and ecosystem functioning in river networks. Yet these processes remain largely overlooked in most river management practices and underlying policies. Here, we propose adoption of a meta-system approach, where regional processes acting at different levels of ecological organization - populations, communities, and ecosystems - are integrated into conventional river conservation, restoration, and biomonitoring. We also describe a series of measurements and indicators that could be assimilated into the implementation of relevant biodiversity and environmental policies. Finally, we highlight the need for alternative management strategies that can guide practitioners toward applying recent advances in ecology to preserve and restore river ecosystems and the ecosystem services they provide, in the context of increasing alteration of river network connectivity worldwide.

Securing Biodiversity, Functional Integrity, and Ecosystem Services in Drying River Networks (DRYvER)

River networks are among Earth’s most threatened hot-spots of biodiversity and provide key ecosystem services (e.g., supply drinking water and food, climate regulation) essential to sustaining human well-being. Climate change and increased human water use are causing more rivers and streams to dry, with devastating impacts on biodiversity and ecosystem services. Currently, more than a half of the global river networks consist of drying channels, and these are expanding dramatically. However, drying river networks (DRNs) have received little attention from scientists and policy makers, and the public is unaware of their importance. Consequently, there is no effective integrated biodiversity conservation or ecosystem management strategy of DRNs.

A multidisciplinary team of 25 experts from 11 countries in Europe, South America, China and the USA will build on EU efforts to assess the cascading effects of climate change on biodiversity, ecosystem functions and ecosystem services of DRNs through changes in flow regimes and water use. DRYvER (DRYing riVER networks) will gather and upscale empirical and modelling data from nine focal DRNs (case studies) in Europe (EU) and Community of Latin American and Caribbean States (CELAC) to develop a meta-system framework applicable to Europe and worldwide. It will also generate crucial knowledge-based strategies, tools and guidelines for economically-efficient adaptive management of DRNs. Working closely with stakeholders and end-users, DRYvER will co-develop strategies to mitigate and adapt to climate change impacts in DRNs, integrating hydrological, ecological (including nature-based solutions), socio-economic and policy perspectives. The end results of DRYvER will contribute to reaching the objectives of the Paris Agreement and placing Europe at the forefront of research on climate change.

Traits affecting nutrient recycling by mobile consumers can explain coexistence and spatially heterogeneous trophic regulation across a meta-ecosystem

Ecosystems are linked through spatial flows of organisms and nutrients that impact their biodiversity and regulation. Theory has predominantly studied passive nutrient flows that occur independently of organism movement. Mobile organisms, however, commonly drive nutrient flows across ecosystems through nutrient recycling. Using a meta-ecosystem model where consumers move between ecosystems, we study how consumer recycling and traits related to feeding and sheltering preferences affect species diversity and trophic regulation. We show local effects of recycling can cascade across space, yielding spatially heterogeneous top-down and bottom-up effects. Consumer traits impact the direction and magnitude of these effects by enabling recycling to favour a single ecosystem. Recycling further modifies outcomes of competition between consumer species by creating a positive feedback on the production of one competitor. Our findings suggest spatial interactions between feeding and recycling activities of organisms are key to predicting biodiversity and ecosystem functioning across spatial scales.

Dispersal syndromes can link intraspecific trait variability and meta-ecosystem functioning

Dispersal mediates the flow of organisms in meta-communities and subsequently energy and material flows in meta-ecosystems. Individuals within species often vary in dispersal tendency depending on their phenotypic traits (i.e., dispersal syndromes), but the implications of dispersal syndromes for meta-ecosystems have been rarely studied. Using empirical examples on vertebrates, arthropods, and microbes, we highlight that key functional traits can be linked to dispersal. We argue that this coupling between dispersal and functional traits can have consequences for meta-ecosystem functioning, mediating flows of functional traits and thus the spatial heterogeneity of ecosystem functions. As dispersal syndromes may be genetically determined, the spatial heterogeneity of functional traits may be further carried over across generations and link meta-ecosystem functioning to evolutionary dynamics.

Warming and top predator loss drive direct and indirect effects on multiple trophic groups within and across ecosystems

The interspecific interactions within and between adjacent ecosystems strongly depend on the changes in their abiotic and biotic components. However, little is known about how climate change and biodiversity loss in a specific ecosystem can impact the multiple trophic interactions of different biological groups within and across ecosystems. We used natural microecosystems (tank-bromeliads) as a model system to investigate the main and interactive effects of aquatic warming and aquatic top predator loss (i.e. trophic downgrading) on trophic relationships in three integrated food web compartments: (a) aquatic micro-organisms, (b) aquatic macro-organisms and (c) terrestrial predators (i.e. via cross-ecosystem effects). The aquatic top predator loss substantially impacted the three food web compartments. In the aquatic macrofauna compartment, trophic downgrading increased the filter feeder richness and abundance directly and indirectly via an increase in detritivore richness, likely through a facilitative interaction. For the microbiota compartment, aquatic top predator loss had a negative effect on algae richness, probably via decreasing the input of nutrients from predator biological activities. Furthermore, the more active terrestrial predators responded more to aquatic top predator loss, via an increase in some components of aquatic macrofauna, than more stationary terrestrial predators. The aquatic trophic downgrading indirectly altered the richness and abundance of cursorial terrestrial predators, but these effects had different direction according to the aquatic functional group, filter feeder or other detritivores. The web-building predators were indirectly affected by aquatic trophic downgrading due to increased filter feeder richness. Aquatic warming did not affect the aquatic micro- or macro-organisms but did positively affect the abundance of web-building terrestrial predators. These results allow us to raise a predictive framework of how different anthropogenic changes predicted for the next decades, such as aquatic warming and top predator loss, could differentially affect multiple biological groups through interactions within and across ecosystems.

Integrated ecosystems: linking food webs through reciprocal resource reliance

Ecosystems are defined, studied, and managed according to boundaries constructed to conceptualize patterns of interest at a certain scale and scope. The distinction between ecosystems becomes obscured when resources from multiple origins cross porous boundaries and are assimilated into food webs through repeated trophic transfers. Ecosystem compartments can define bounded localities in a heterogeneous landscape that simultaneously retain and exchange energy in the form of organic matter. Here we developed and tested a framework to quantify reciprocal reliance on cross-boundary resource exchange and calculate the contribution of primary production from adjacent ecosystem compartments cycling through food webs to support consumers at different trophic levels. Under this framework, an integrated ecosystem can be measured and designated when the boundary between spatially distinct compartments is permeable and the bidirectional exchange of resources contributes significantly to sustaining both food webs. Using a desert river and riparian zone as a case study, we demonstrate that resources exchanged across the aquatic-riparian boundary cycle through multiple trophic levels. Furthermore, predators on both sides of the boundary were supported by externally produced resources to a similar extent, indicating this is a tightly integrated river-riparian ecosystem and that changes to either compartment will substantially impact the other. Using published data on lake ecosystems, we demonstrated that benthic and pelagic ecosystem compartments are likely not fully integrated, but differences between lakes could be used to test ecological hypotheses. Finally, we discuss how the integrated ecosystem framework could be applied in urban-preserve and field-forest ecosystems to address a broad range of ecological concepts. Because few systems function in complete isolation, this novel approach has application to research and management strategies globally as ecosystems continue to face novel pressures that precipitate cascading ecological repercussions well beyond a bounded system of focus.

Global Connectivity of Southern Ocean Ecosystems

Southern Ocean ecosystems are globally important. Processes in the Antarctic atmosphere, cryosphere, and the Southern Ocean directly influence global atmospheric and oceanic systems. Southern Ocean biogeochemistry has also been shown to have global importance. In contrast, ocean ecological processes are often seen as largely separate from the rest of the global system. In this paper, we consider the degree of ecological connectivity at different trophic levels, linking Southern Ocean ecosystems with the global ocean, and their importance not only for the regional ecosystem but also the wider Earth system. We also consider the human system connections, including the role of Southern Ocean ecosystems in supporting society, culture, and economy in many nations, influencing public and political views and hence policy. Rather than Southern Ocean ecosystems being defined by barriers at particular oceanic fronts, ecological changes are gradual due to cross-front exchanges involving oceanographic processes and organism movement. Millions of seabirds and hundreds of thousands of cetaceans move north out of polar waters in the austral autumn interacting in food webs across the Southern Hemisphere, and a few species cross the equator. A number of species migrate into the east and west ocean-basin boundary current and continental shelf regions of the major southern continents. Human travel in and out of the Southern Ocean region includes fisheries, tourism, and scientific vessels in all ocean sectors. These operations arise from many nations, particularly in the Northern Hemisphere, and are important in local communities as well as national economic, scientific, and political activities. As a result of the extensive connectivity, future changes in Southern Ocean ecosystems will have consequences throughout the Earth system, affecting ecosystem services with socio-economic impacts throughout the world. The high level of connectivity also means that changes and policy decisions in marine ecosystems outside the Southern Ocean have consequences for ecosystems south of the Antarctic Polar Front. Knowledge of Southern Ocean ecosystems and their global connectivity is critical for interpreting current change, projecting future change impacts, and identifying integrated strategies for conserving and managing both the Southern Ocean and the broader Earth system.

A methodological roadmap to quantify animal-vectored spatial ecosystem subsidies

Energy, nutrients and organisms move over landscapes, connecting ecosystems across space and time. Meta-ecosystem theory investigates the emerging properties of local ecosystems coupled spatially by these movements of organisms and matter, by explicitly tracking exchanges of multiple substances across ecosystem borders. To date, meta-ecosystem research has focused mostly on abiotic flows-neglecting biotic nutrient flows. However, recent work has indicated animals act as spatial nutrient vectors when they transport nutrients across landscapes in the form of excreta, egesta and their own bodies. Partly due to its high level of abstraction, there are few empirical tests of meta-ecosystem theory. Furthermore, while animals may be viewed as important mediators of ecosystem functions, better integration of tools is needed to develop predictive insights of their relative roles and impacts on diverse ecosystems. We present a methodological roadmap that explains how to do such integration by discussing how to combine insights from movement, foraging and ecosystem ecology to develop a coherent understanding of animal-vectored nutrient transport on meta-ecosystems processes. We discuss how the slate of newly developed technologies and methods-tracking devices, mechanistic movement models, diet reconstruction techniques and remote sensing-that when integrated have the potential to advance the quantification of animal-vectored nutrient flows and increase the predictive power of meta-ecosystem theory. We demonstrate that by integrating novel and established tools of animal ecology, ecosystem ecology and remote sensing, we can begin to identify and quantify animal-mediated nutrient translocation by large animals. We also provide conceptual examples that show how our proposed integration of methodologies can help investigate ecosystem impacts of large animal movement. We conclude by describing practical advancements to understanding cross-ecosystem contributions of animals on the move. Understanding the mechanisms by which animals shape ecosystem dynamics is important for ongoing conservation, rewilding and restoration initiatives around the world, and for developing more accurate models of ecosystem nutrient budgets. Our roadmap will enable ecologists to better qualify and quantify animal-mediated nutrient translocation for animals on the move.

Incorporating abiotic controls on animal movements in metacommunities

Local dynamics are influenced by regional processes. Meta-ecology, or the study of spatial flows of energy, materials, and species between local systems, is becoming increasingly concerned with accurate depictions of species movements and the impacts of this movement on landscape-level ecosystem function. Indeed, incorporating diverse types of movement is a major frontier in metacommunity theory. Here, we synthesize literature to demonstrate that the movement of organisms between patches is governed by the interplay between both a species' ability to move and the combined effects of landscape structure and physical flows (termed abiotic controls), which together we refer to as abiotic-dependent species connectivity. For example, two lakes that share geographic proximity may be inaccessible for mobile fish species because they lack a river connecting them (landscape structure), but wind currents may disperse insects between them (physical flows). Empirical evidence suggests that abiotic controls, such as ocean currents, lead to abiotic-dependent species connectivity and that, in nature, this type of connectivity is the rule rather than the exception. Based on this empirical evidence, we introduce a novel mathematical framework to demonstrate how species movement capabilities and abiotic conditions, can interact to influence metacommunity stability. We apply this framework to predict how incorporating abiotic-dependent species connectivity applies to classic empirical examples of aquatic, aquatic-terrestrial, and terrestrial experimental metacommunities. We demonstrate that incorporating abiotic-dependent species connectivity into metacommunity models can lead to a much broader range of dynamics than models previously predicted, including a wider range of metacommunity stability. Our framework fills critical gaps in our basic understanding of organismal movement across landscapes and provides testable predictions for how such common natural phenomena impact landscape-level ecosystem function. Finally, we present future perspectives for further development of meta-ecological theory from questions about fragmentation to ecosystems. Anthropogenic change is not only leading to habitat loss from the damming of rivers to denuding the landscape, but altering the physical flows that have historically connected communities. Thus, recognizing the importance of these processes in tandem with species' movement abilities is critical for predicting and preserving the structure and function of ecological communities.

The effects of resource subsidy duration in a detritus-based stream ecosystem: A mesocosm experiment

Most resource subsidies are temporally variable, dynamically affecting the consumer populations, community structures and ecosystem functions of recipient ecosystems. Temporally variable resource subsidies are characterized by the duration, magnitude, timing and frequency of resource subsidy inputs. These different characteristics may have different mechanisms by which to affect recipient ecosystems. Few studies have examined the duration of resource subsidy inputs on recipient ecosystems, although there exist previous studies focusing on magnitude, timing and frequency. We provide the first experimental test of the effects of subsidy duration on a stream ecosystem by using an outdoor mesocosm experiment, in which we directly manipulated the subsidy duration (pulsed vs. prolonged) of terrestrial invertebrate input into the mesocosm. Given the same overall amount of terrestrial invertebrate subsidy was added, a prolonged subsidy allowed large-stage fish to effectively monopolize the subsidy over small-stage fish, which led small-stage fish to maintain their predation pressure on in-situ prey, that is, benthic invertebrates. On the other hand, a pulsed subsidy allowed small-stage fish to increase their feeding rate of the subsidy and to become away from foraging in-situ prey. Consequently, weaker indirect positive effects on in-situ benthic prey and leaf break-down rate were found with the prolonged versus pulsed subsidy. However, these indirect effects varied by the dominant benthic prey species, which differed in edibility for fish. Such predator-specific vulnerability of benthic prey can be important in mediating trophic cascades in detritus-based stream food webs. Phenological events that generate temporal subsidies (e.g. salmon spawning run and arthropod emergence) can be synchronized (pulsed) or desynchronized (prolonged) within and among species, depending on the degree of spatial and temporal environmental heterogeneity. The effects of subsidy duration would thus be important to better understand ecological processes in spatially and temporally coupled ecosystems.

Converting Ecological Currencies: Energy, Material, and Information Flows

Understanding how the three currencies of life - energy, material, and information - interact is a key step towards synthesis in ecology and evolution. However, current theory focuses on the role of matter as a resource and energy, and typically ignores how the same matter can have other important effects as a carrier of information or modifier of the environment. Here we present the hypothesis that the dynamic conversion of matter by organisms among its three currencies mediates the structure and function of ecosystems, and that these effects can even supersede the effects of matter as a resource. Humans are changing the information in the environment and this is altering species interactions and flows of matter within and among ecosystems.

On the Occurrence of Metadiaptomus chevreuxi (Calanoida, Diaptomidae, Paradiaptominae) in the Iberian Peninsula, With Notes on the Ecology and Distribution of its European Populations

Temporary ponds are one of the most peculiar ecosystems in the world, being characterized by an extraordinarily rich crustacean fauna, with a high degree of endemism. Among them, diaptomid copepods are among the most biogeographically interesting taxa. However, the present knowledge on diaptomid distribution is still far from being exhaustive, even in the relatively well-studied western European countries. In this study, we report the first record of the diaptomid calanoid copepod Metadiaptomus chevreuxi for the Iberian Peninsula, where it was collected in five temporary ponds in Andalusia (Spain). The characteristics of the new sites are described, the literature dealing with the European localities of the species is reviewed, and a molecular phylogenetic tree has been built, based on new and previously available mitochondrial DNA sequences, thus expanding the knowledge on the ecology and phylogeography of this rare species. The species mainly occupies small isolated temporary ponds in (semi-)arid regions, suggesting adaptations to unpredictable aquatic habitats. The existence of two molecular clades separating the Iberian from the Sicilian and Tunisian populations supports the existence of a longitudinal long-term disjunction, whereas the north-south flow is probably facilitated by migrating birds. Further research on the biota of the small water bodies of the western Mediterranean area may help to expand our knowledge on rare aquatic species, such as M. chevreuxi, and to better interpret their natural history.

Movement-mediated community assembly and coexistence

Organismal movement is ubiquitous and facilitates important ecological mechanisms that drive community and metacommunity composition and hence biodiversity. In most existing ecological theories and models in biodiversity research, movement is represented simplistically, ignoring the behavioural basis of movement and consequently the variation in behaviour at species and individual levels. However, as human endeavours modify climate and land use, the behavioural processes of organisms in response to these changes, including movement, become critical to understanding the resulting biodiversity loss. Here, we draw together research from different subdisciplines in ecology to understand the impact of individual-level movement processes on community-level patterns in species composition and coexistence. We join the movement ecology framework with the key concepts from metacommunity theory, community assembly and modern coexistence theory using the idea of micro-macro links, where various aspects of emergent movement behaviour scale up to local and regional patterns in species mobility and mobile-link-generated patterns in abiotic and biotic environmental conditions. These in turn influence both individual movement and, at ecological timescales, mechanisms such as dispersal limitation, environmental filtering, and niche partitioning. We conclude by highlighting challenges to and promising future avenues for data generation, data analysis and complementary modelling approaches and provide a brief outlook on how a new behaviour-based view on movement becomes important in understanding the responses of communities under ongoing environmental change.