Levels Of Ecological Organization Research Articles

Heterotrophy in marine animal forests in an era of climate change.

Marine animal forests (MAFs) are benthic ecosystems characterised by biogenic three-dimensional structures formed by suspension feeders such as corals, gorgonians, sponges and bivalves. They comprise highly diversified communities among the most productive in the world's oceans. However, MAFs are in decline due to global and local stressors that threaten the survival and growth of their foundational species and associated biodiversity. Innovative and scalable interventions are needed to address the degradation of MAFs and increase their resilience under global change. Surprisingly, few studies have considered trophic interactions and heterotrophic feeding of MAF suspension feeders as an integral component of MAF conservation. Yet, trophic interactions are important for nutrient cycling, energy flow within the food web, biodiversity, carbon sequestration, and MAF stability. This comprehensive review describes trophic interactions at all levels of ecological organisation in tropical, temperate, and cold-water MAFs. It examines the strengths and weaknesses of available tools for estimating the heterotrophic capacities of the foundational species in MAFs. It then discusses the threats that climate change poses to heterotrophic processes. Finally, it presents strategies for improving trophic interactions and heterotrophy, which can help to maintain the health and resilience of MAFs.

BatFly: A database of Neotropical bat-fly interactions.

Global changes have increased the risk of emerging infectious diseases, which can be prevented or mitigated by studying host-parasite interactions, among other measures. Bats and their ectoparasitic flies of the families Streblidae and Nycteribiidae are an excellent study model but, so far, our knowledge has been restricted to fragmented records at a local scale. To help boost research, we assembled a data set of bat-fly interactions from 174 studies published between 1904 and 2022 plus three original data sets. Altogether, these studies were carried out at 650 sites in the Neotropics, mainly distributed in Mexico, Brazil, Argentina, southern USA, and Colombia, among other countries. In total, our data set contains 3984 interaction records between 237 bat species and 255 fly species. The bat species with the largest number of recorded interactions were Carollia perspicillata (357), Artibeus jamaicensis (263), and Artibeus lituratus (228). The fly species with the largest number of recorded interactions were Trichobius joblingi (256), Megistopoda aranea (235), and Megistopoda proxima (215). The interaction data were extracted, filtered, taxonomically harmonized, and made available in a tidy format together with linked data on bat population, fly population, study reference, sampling methods and geographic information from the study sites. This interconnected structure enables the expansion of information for each interaction record, encompassing where and how each interaction occurred, as well as the number of bats and flies involved. We expect BatFly to open new avenues for research focused on different levels of ecological organization and spatial scales. It will help consolidate knowledge about ecological specialization, resource distribution, pathogen transmission, and the drivers of parasite prevalence over a broad spatial range. It may also help to answer key questions such as: Are there differences in fly prevalence or mean infestation across Neotropical ecoregions? What ecological drivers explain those differences? How do specialization patterns vary among fly species in the Neotropics? Furthermore, we expect BatFly to inspire research aimed at understanding how climate and land-use changes may impact host-parasite interactions and disease outbreaks. This kind of research may help us reach Sustainable Development Goal 3, Good Health and Wellbeing, outlined by the United Nations. The data are released under a Creative Commons Attribution 4.0 International License.

Field studies of the ecological impacts of invasive plants in Europe

The impacts of invasive species can vary widely across invaded sites and depend on the ecological variable of study. In this paper, we describe the first harmonised database that compiles scientific evidence of the ecological impacts of invasive plant species at continental scale. We summarise results from 266 publications reporting 4259 field studies on 104 invasive species in 29 European countries. For each study, we recorded whether the effects were statistically significant and noted their direction (i.e. decrease or increase in the response variable when compared to uninvaded sites). We classified studies, based on the impacts on the levels of ecological organisation (species, communities and ecosystems), taxa and trophic level. More than half of the studies were conducted in temperate and boreal forests and woodlands and temperate grasslands. Notably, one third of the studies focused on just five invasive species. Most studies were on native species followed by studies on communities. Impacts on plants were more frequently studied than impacts on other taxa and trophic groups. Overall, 43% of the studies reported significant impacts, with more significant decreases (26%) than increases (17%) in the response variables. Significant impacts were more frequent on species and communities than on ecosystems; and on plants than on animals or microbes. This database is of interest for academic, management and policy-related purposes.

Climatic effects on the synchrony and stability of temperate headwater invertebrates over four decades.

Important clues about the ecological effects of climate change can arise from understanding the influence of other Earth-system processes on ecosystem dynamics but few studies span the inter-decadal timescales required. We, therefore, examined how variation in annual weather patterns associated with the North Atlantic Oscillation (NAO) over four decades was linked to synchrony and stability in a metacommunity of stream invertebrates across multiple, contrasting headwaters in central Wales (UK). Prolonged warmer and wetter conditions during positive NAO winters appeared to synchronize variations in population and community composition among and within streams thereby reducing stability across levels of ecological organization. This climatically mediated synchronization occurred in all streams irrespective of acid-base status and land use, but was weaker where invertebrate communities were more functionally diverse. Wavelet linear models indicated that variation in the NAO explained up to 50% of overall synchrony in species abundances at a timescale of 4-6 years. The NAO appeared to affect ecological dynamics through local variations in temperature, precipitation and discharge, but increasing hydrochemical variability within sites during wetter winters might have contributed. Our findings illustrate how large-scale climatic fluctuations generated over the North Atlantic can affect population persistence and dynamics in inland freshwater ecosystems in ways that transcend local catchment character. Protecting and restoring functional diversity in stream communities might increase their stability against warmer, wetter conditions that are analogues of ongoing climate change. Catchment management could also dampen impacts and provide options for climate change adaptation.

Light pollution in complex ecological systems.

Light pollution has emerged as a burgeoning area of scientific interest, receiving increasing attention in recent years. The resulting body of literature has revealed a diverse array of species-specific and context-dependent responses to artificial light at night (ALAN). Because predicting and generalizing community-level effects is difficult, our current comprehension of the ecological impacts of light pollution on complex ecological systems remains notably limited. It is critical to better understand ALAN's effects at higher levels of ecological organization in order to comprehend and mitigate the repercussions of ALAN on ecosystem functioning and stability amidst ongoing global change. This theme issue seeks to explore the effects of light pollution on complex ecological systems, by bridging various realms and scaling up from individual processes and functions to communities and networks. Through this integrated approach, this collection aims to shed light on the intricate interplay between light pollution, ecological dynamics and humans in a world increasingly impacted by anthropogenic lighting. This article is part of the theme issue 'Light pollution in complex ecological systems'.

Deterioration of the Littoral–Benthic Ecosystem Following Recent Expansion of Signal Crayfish (Pacifastacus leniusculus) in the World’s Clearest Large Lake

Some biological invasions can result in algae blooms in the nearshore of clear lakes. We studied if an invasive crayfish (Pacifastacus leniusculus) modified the biomass and community composition of benthic macroinvertebrates and therefore led to a trophic cascade resulting in increased periphyton biomass, elevated littoral primary productivity, and benthic algae bloom in a lake with remarkable transparency [Crater Lake, Oregon, USA]. After quantifying the changes in the spatial distribution of invasive crayfish over a 13-year period, we compared biomass and community composition of littoral–benthic macroinvertebrates, periphyton biovolume, community composition, nutrient limitation, and the development of benthic algae bloom in locations with high and low crayfish density. In addition, we determined if the alteration in community structure resulted in directional changes to gross primary production and ecosystem respiration. The extent of crayfish distribution along the shoreline of Crater Lake doubled over a 13-year period, leaving less than 20% of the shoreline free from crayfish. At high crayfish density sites, benthic macroinvertebrate biomass was 99% lower, and taxa richness was 50% lower than at low crayfish areas. High crayfish sites show tenfold greater periphyton biovolume, sixfold higher periphyton biomass (chlorophyll a), twofold higher metabolic productivity, and the presence of large filamentous algae (Cladophora sp.). The invasion of crayfish had negative consequences for a lake protected under the management of the USA National Park Service, with direct impacts on many levels of ecological organization.

Ecosystem size filters life-history strategies to shape community assembly in lakes.

Enhancing understanding of community assembly rules hinges on shared conceptualizations that operate across scales and levels of ecological organization. Knowledge of the biogeography of life-history strategies is especially limited but crucial for building fundamental information on the relationships between trait diversity and species richness. The goals of this study were to (i) demonstrate how life histories can be classified using a previously identified triangular continuum of evolutionary trade-offs; (ii) test whether spatial and temporal heterogeneity in species abundances is linked to life-history strategy; (iii) compare species-area relationships across the primary life-history strategist groups and (iv) explore how species life-history niche spaces are shaped by ecosystem size and landscape architecture. Fish communities were sampled in 40 lakes that varied widely in volume; 11 lakes were sampled annually for 28 or 42 years. Seventy-one species were classified as equilibrium, periodic or opportunistic strategists, and species-area curves were quantified and compared among strategy types. As predicted by life-history theory, relative abundances of opportunistic strategists were extremely variable over space and time, whereas abundances of equilibrium and periodic strategists were more stable. Small lakes were often dominated by only one species, usually an opportunistic strategist. Species richness increased with ecosystem size, but larger ecosystems were increasingly inhabited by equilibrium, and then, periodic strategists. Richness of periodic species increased with ecosystem size at a faster rate compared with opportunistic species showing that colonization-extinction points fundamentally vary by strategy. Similarly, life-history niche space increased with ecosystem size in accord with species-area relationships but showed saturation behaviour. Niche space became increasingly crowded in large lakes, particularly in lakes with higher hydrologic connectance. Ecosystem size mediates the assembly of communities through effects on environmental stability, hydrology and life-history filtering. This finding provides novel insights into community assembly at multiple scales and has broad conservation applications. Because ecosystem size filters towards orthogonal and inverse life histories, conservation actions (e.g. fish stockings) that do not consider life-history and community filtering rules will probably fail.

Contrasting the effects of microplastic types, concentrations and nutrient enrichment on freshwater communities and ecosystem functioning

Microplastics are now ubiquitous in freshwater environments. As most previous research has focused on species-specific effects of microplastics under controlled laboratory conditions, little is known about the impact of microplastics at higher levels of ecological organisation, such as freshwater communities and their associated ecosystem functions. To fill this knowledge gap, an outdoor experiment using 40 freshwater mesocosms, each 1.57 m3, was used to determine the effects of (i) microplastic type: traditional oil-based high-density polyethylene versus bio-based biodegradable polylactic acid, (ii) concentration of microplastic particles and (iii) nutrient enrichment. The two concentrations of microplastics used were equivalent to measured environmentally occurring concentrations and concentrations known to cause toxicological effects under laboratory conditions. Freshwater communities are also at increasing risk from nutrient enrichment, which can alter community composition in favour of competitively dominant taxa. The independent and interactive effects of these treatments on pelagic community structure (phytoplankton standing stock, taxonomic richness, and composition) and ecosystem functioning (periphyton productivity and leaf litter decomposition) were assessed. Taxonomic richness and community composition were not affected by exposure to the experimental treatments and there were no significant treatment effects on phytoplankton standing stock, periphyton productivity, total or microbial leaf litter decomposition. Overall, multiple microplastic exposures, crossed with nutrient addition had little impact on the structure and functioning of semi-natural freshwater ecosystems. These findings indicate that the negative impacts of microplastics predicted from species-specific studies may not be readily realised at the ecosystem scale.

Nitrogen addition and mowing alter drought resistance and recovery of grassland communities.

Nitrogen enrichment and land use are known to influence various ecosystems, but how these anthropogenic changes influence community and ecosystem responses to disturbance remains poorly understood. Here we investigated the effects of increased nitrogen input and mowing on the resistance and recovery of temperate semiarid grassland experiencing a three-year drought. Nitrogen addition increased grassland biomass recovery but decreased structural recovery after drought, whereas annual mowing increased grassland biomass recovery and structural recovery but reduced structural resistance to drought. The treatment effects on community biomass/structural resistance and recovery were largely modulated by the stability of the dominant species and asynchronous dynamics among species, and the community biomass resistance and recovery were also greatly driven by the stability of grasses. Community biomass resistance/recovery in response to drought was positively associated with its corresponding structural stability. Our study provides important experimental evidence that both nitrogen addition and mowing could substantially change grassland stability in both functional and structural aspects. Our findings emphasize the need to study changes across levels of ecological organization for a more complete understanding of ecosystem responses to disturbances under widespread environmental changes.

Per-capita impacts of an invasive grass vary across levels of ecological organization in a tropical savanna

Per-capita impacts of an invasive grass vary across levels of ecological organization in a tropical savanna

Species portfolio effects dominate seasonal zooplankton stabilization within a large temperate lake.

Portfolio effects (PEs) in ecology refer to the suite of phenomenon where the temporal variation of aggregate ecosystem properties (i.e., abundance) is lower than that of their ecosystem components. An example of this is where differential responses of species to environmental variation generate stability at higher levels of ecological organization (e.g., local community, metapopulation, metacommunity). Most of the research examining such PEs has focused on spatial or interannual variation of ecosystems; however, as global change continues to alter seasonality and ecosystem functioning, understanding the underlying food web structures that help maintain stability at multiple spatial and temporal scales is critical to managing ecological systems. Recent advances investigating diversity-stability relationships has led to the development of frameworks that incorporate a metacommunity perspective which allows for the partitioning of PEs across organizational scales (i.e., local community, metapopulation, cross-community, metacommunity) from local population dynamics (total). This partitioning yields insights into the mechanisms that generate observed PEs in nature. Here, we employed one of these recently developed frameworks on a temporally (1986-1999, 2008-2019) and spatially (five sampling stations, local communities) extensive data set of zooplankton abundance (e.g., density) within a large temperate lake to investigate how temporal (seasonal) and spatial (among site) PEs influence stability within the zooplankton metacommunity. We found that seasonal asynchrony of different zooplankton species within local communities and across communities generated the vast majority of stabilization, while spatial (i.e., metapopulation) dynamics were more synchronous and contributed little to overall system stability. Furthermore, significantly positive diversity-asynchrony relationships at the total, local- and cross-community scales were found as asynchrony was positively correlated with local Shannon diversity. Last, a comparison of PEs over the time periods, during which significant local and global changes (i.e., climate warming, invasive species) have occurred suggests that PEs may be eroding, as increasingly synchronous dynamics and declining diversity in recent years have led to a rise in metacommunity variability. We end by arguing for the critical importance of understanding seasonally driven stabilizing mechanisms as local and global changes threaten to fundamentally alter seasonal signals with potentially strong implications for the structures that lend stability to ecosystems.

Identifying individual and spatial drivers of heterogeneous transmission and virulence of malaria in Caribbean anoles

AbstractHeterogeneous distributions are a fundamental principle of ecology, manifesting as natural variability within ecological levels of organization from individuals to ecosystems. In disease ecology, variability in biotic and abiotic factors can result in heterogeneous patterns of transmission and virulence—broadly defined here as the negative consequences of infection. Still, our classic theoretical understanding of disease dynamics comes from models that assume homogeneous transmission and virulence. Here, we test this assumption by assessing the contribution of various sources of individual and spatial heterogeneity to patterns of transmission and sublethal measurements of virulence in two lizard–malaria systems: a three‐parasite assemblage (Plasmodium floridense,Plasmodium leukocytica, andPlasmodium azurophilum) infecting the lizardAnolis gundlachiin the rainforest of Puerto Rico and a single‐parasite system (P. floridense–Anolis sagrei) in Florida. Using a Bayesian model selection framework, we evaluated whether individual host differences (i.e., body size and sex) or spatial variability (i.e., habitat type and local‐scale host spatial structure) drive heterogeneity in the probability of infection or its associated health costs (i.e., body condition, blood chemistry). We found that the probability of infection increases with increasing lizard body size in both systems. However, in Florida, we found the relationship to be subdued in deforested habitats compared to the adjacent urban hydric forests. Furthermore, infection was spatially clustered within sampling sites, with “hot” and “cold” spots across the landscape. Nevertheless, we found no clear evidence of costs of infection on lizard health in any of the measures assessed and hence no grounds for inference regarding heterogeneous virulence. Ultimately, the consistency of our results across systems suggests prominent roles of individual and spatial heterogeneities as driving factors of transmission of vector‐borne diseases.

Links across ecological scales: Plant biomass responses to elevated CO2.

The degree to which elevated CO2 concentrations (e[CO2 ]) increase the amount of carbon (C) assimilated by vegetation plays a key role in climate change. However, due to the short-term nature of CO2 enrichment experiments and the lack of reconciliation between different ecological scales, the effect of e[CO2 ] on plant biomass stocks remains a major uncertainty in future climate projections. Here, we review the effect of e[CO2 ] on plant biomass across multiple levels of ecological organization, scaling from physiological responses to changes in population-, community-, ecosystem-, and global-scale dynamics. We find that evidence for a sustained biomass response to e[CO2 ] varies across ecological scales, leading to diverging conclusions about the responses of individuals, populations, communities, and ecosystems. While the distinct focus of every scale reveals new mechanisms driving biomass accumulation under e[CO2 ], none of them provides a full picture of all relevant processes. For example, while physiological evidence suggests a possible long-term basis for increased biomass accumulation under e[CO2 ] through sustained photosynthetic stimulation, population-scale evidence indicates that a possible e[CO2 ]-induced increase in mortality rates might potentially outweigh the effect of increases in plant growth rates on biomass levels. Evidence at the global scale may indicate that e[CO2 ] has contributed to increased biomass cover over recent decades, but due to the difficulty to disentangle the effect of e[CO2 ] from a variety of climatic and land-use-related drivers of plant biomass stocks, it remains unclear whether nutrient limitations or other ecological mechanisms operating at finer scales will dampen the e[CO2 ] effect over time. By exploring these discrepancies, we identify key research gaps in our understanding of the effect of e[CO2 ] on plant biomass and highlight the need to integrate knowledge across scales of ecological organization so that large-scale modeling can represent the finer-scale mechanisms needed to constrain our understanding of future terrestrial C storage.

Predicting the effects of multiple global change drivers on microbial communities remains challenging.

Microbial communities in many ecosystems are facing a broad range of global change drivers, such as nutrient enrichment, chemical pollution, and temperature change. These drivers can cause changes in the abundance of taxa, the composition of communities, and the properties of ecosystems. While the influence of single drivers is already described in numerous studies, the effect and predictability of multiple drivers changing simultaneously is still poorly understood. In this study, we used 240 highly replicable oxic/anoxic aquatic lab microcosms and four drivers (fertilizer, glyphosate, metal pollution, antibiotics) in all possible combinations at three different temperatures (20, 24, and 28°C) to shed light into consequences of multiple drivers on different levels of organization, ranging from species abundance to community and ecosystem parameters. We found (i) that at all levels of ecological organization, combinations of drivers can change the biological consequence and direction of effect compared to single drivers, (ii) that effects of combinations are further modified by temperature, (iii) that a larger number of drivers occurring simultaneously is often quite closely related to their effect size, and (iv) that there is little evidence that any of these effects are associated with the level of ecological organization of the state variable. These findings suggest that, at least in this experimental ecosystem approximating a stratified aquatic ecosystem, there may be relatively little scope for predicting the effects of combinations of drivers from the effects of individual drivers, or by accounting for the level of ecological organization in question, though there may be some scope for prediction based on the number of drivers that are occurring simultaneous. A priority, though also a considerable challenge, is to extend such research to consider continuous variation in the magnitude of multiple drivers acting together.

Impacts of a novel controlled-release TiO2-coated (nano-) formulation of carbendazim and its constituents on freshwater macroinvertebrate communities

Recently, the delivery of pesticides through novel controlled-release (nano-)formulations has been proposed intending to reduce (incidental) pesticide translocation to non-target sites. Concerns have however been raised with regards to the potentially enhanced toxicity of controlled-release (nano-)formulations to non-target organisms and ecosystems. We evaluated long-term (i.e. 1 and 3 month-) impacts of a novel controlled-release pesticide formulation (nano-TiO2-coated carbendazim) and its individual and combined constituents (i.e. nano-sized TiO2 and carbendazim) on naturally established freshwater macroinvertebrate communities. In doing so, we simultaneously assessed impacts of nano-sized TiO2 (nTiO2), currently one of the most used and emitted engineered nanomaterials world-wide. We determined ecological impacts on diversity (i.e. β-diversity), structure (i.e. rank abundance parameters), and functional composition (i.e. feeding guilds & trophic groups) of communities and underlying effects at lower organizational levels (i.e. population dynamics of individual taxa). Freshwater macroinvertebrate communities were negligibly impacted by nTiO2 at environmentally realistic concentrations. The controlled-release (nano-)formulation significantly delayed release of carbendazim to the water column. Nevertheless, conventional- (i.e. un-coated-) and nTiO2-coated carbendazim induced a similar set of adverse impacts at all investigated levels of ecological organization and time points. Our findings show fundamental restructuring of the taxonomic- and functional composition of macroinvertebrate communities as a result of low-level pesticide exposure, and thereby highlight the need for mitigating measures to reduce pesticide-induced stress on freshwater ecosystems.

State of the antioxidant defense system in wedge clams from Bulgarian Black Sea as a measure of resistance to environmental impacts

Pollution and climate change can induce oxidative stress (OS) in aquatic organisms. Reduced activity or incoordination between antioxidant enzymes in marine bivalves may cause cellular impairment with effects on higher levels of ecological organization. The present study aims to assess the condition factor and the activity of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST), and glutathione concentration (GSH) in soft tissues of Donax trunculus (Linnaeus, 1758) as indicators of the state of marine ecosystems along the Bulgarian Black Sea coast. The wedge clams were sampled manually from different localities in June and in September. The activity of antioxidant enzymes and GSH concentrations varied both seasonally and among localities. Higher values of GSH, SOD and GPx were registered in wedge clams collected in autumn compared to those collected in summer. In wedge clams higher activity of the major phase II detoxification enzyme GST was observed in summer at localities with intensive tourism, suggesting an activation of the cell detoxification processes, presumably in response to increased environmental pressure. In conclusion, the observed presence of elevated enzyme activities suggested activation of the antioxidant protection system of the wedge clams in response to environmental pressure, indicating their ability to cope with induced OS and adapt to local conditions, and thus maintain ecosystem health.

Behavioral Variables to Assess the Toxicity of Unionized Ammonia in Aquatic Snails: Integrating Movement and Feeding Parameters

Behavioral endpoints are important parameters to assess the effects of toxicants on aquatic animals. These endpoints are useful in ecotoxicology because several toxicants modify the animal behavior, which may cause adverse effects at higher levels of ecological organization. However, for the development of new bioassays and for including the behavior in ecotoxicological risk assessment, the comparison of sensitivity between different behavioral endpoints is necessary. Additionally, some toxicants remain in aquatic environments for a few hours or days, which may lead to animal recovery after toxicant exposure. Our study aimed to assess the effect of unionized ammonia on the movement and feeding behaviors of the aquatic gastropod Potamopyrgus antipodarum (Tateidae, Mollusca) and its recovery after exposure. Four treatments were used: a control and three nominal concentrations of unionized ammonia (0.25, 0.5 and 1 mg N-NH3/L). Each treatment was replicated eight times, with six animals in each replicate. Animals were exposed to unionized ammonia for 48 h (exposure period) and, subsequently, to control water for 144 h (post-exposure period). Two movement variables were monitored without food and five feeding behavioral variables were monitored in the presence of food. Some of the feeding behavioral variables showed higher sensitivity (LOEC = 0.25–0.5 mg N-NH3/L) than the movement behavior variables monitored without food (LOEC = 1 mg N-NH3/L). After exposure to unionized ammonia, animals showed a recovery of most behavioral endpoints. The inclusion of post-exposure period and feeding behaviors in bioassays may make studies more realistic, which is crucial for a proper ecotoxicological risk assessment.

Eutrophication‐driven eco‐evolutionary dynamics indicated by differences in stoichiometric traits among populations of Daphnia pulicaria

Abstract Microevolution can have consequences at higher levels of ecological organization. Although divergence among populations can be rapid and driven by anthropogenic changes to the environment, the ecological relevance of evolution induced by human activities remains poorly understood. A frequent way in which human activities drive microevolution is the increase in supply of nutrients such as phosphorus (P) that are required for fitness‐relevant traits such as growth and reproduction. Because higher P concentrations decrease P‐use efficiency and feeding rate in heterotrophic consumers such as Daphnia, we hypothesized that such adjustments should alter consumer–resource dynamics. We examined how cultural eutrophication in temperate lakes causes trait variation in the grazer Daphnia pulicaria. We tested for variation in Daphnia traits and genetic variation in the metabolic enzyme phosphoglucose isomerase (Pgi) which are each known to respond to eutrophication. We then examined the impact of this variation on consumer–resource dynamics using a combination of experiments and a multi‐lake survey. We found that Daphnia from hypereutrophic lakes responded to experimental hypereutrophic conditions with increased growth rates and fecundity when raised on P‐fertilized seston, but had reduced performance on P‐poor seston relative to eutrophic source Daphnia. These results suggest that Daphnia may face a trade‐off in performance at low versus excess P that may be mediated in part by genetic variation at the Pgi locus. The variation observed in laboratory growth experiments scaled up to Daphnia populations in both mesocosm experiments and among lakes. In both the mesocosm experiment and in the lake survey, Daphnia from hypereutrophic source lakes reached high biomass while phytoplankton biomass also remained high. Given the prevalence and rapid eutrophication of freshwater ecosystems worldwide, these results indicate that considering the potential effects of evolutionary change in ecosystem models could be useful in forecasting the effects of anthropogenic environmental change on pivotal ecosystem services.

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.

Using phylogenetic information to impute missing functional trait values in ecological databases

Trait-based approaches offer complementary views to the classic taxonomic approach, which is a crucial step forward to unveil mechanisms of community assembly, species interactions, ecosystem functioning, and tackling important conservation issues. These approaches require an enormous sampling effort to provide complete trait datasets, consequently, missing data are very common. We evaluated the performance of the missForest algorithm, that uses the Random Forest method to impute species traits values using phylogenetic information. We simulated datasets with different sizes and proportions of missing data, different levels of trait conservatism, and trait correlation. We tested trait imputation using the missForest algorithm without phylogenetic information and adding the phylogenetic relationship among species, using phylogenetic eigenvector. Our results show that the level of phylogenetic signal in traits and the correlation among them are the main parameters that influence the measures of imputation error. The measures of errors are smaller when traits have higher levels of correlation and when traits are conserved in the phylogenetic tree. In general, the inclusion of phylogenetic vectors as predictors in the missForest algorithm improves the estimation of missing values. However, the importance of phylogenetic information to the imputation process depends on the proportion of missing entries, phylogenetic conservatism of traits, and the correlation among traits. The missForest algorithm seems to be a robust method for trait imputation, and it can be used to estimate missing traits without the exclusion of species. Thus, we expect to have contributed with a new step to guide methodological choices to impute entire databases of traits with the goal of decreasing uncertainties and bias in the interpretation of ecological patterns and processes at different levels of ecological organization.