Pondscapes, networks of closely situated ponds within a landscape, can provide important habitat for freshwater biodiversity and are increasingly considered to be valuable elements in nature restoration. Understanding how communities build up in newly created pondscapes is important for improving pond creation as a restoration tool. This study aimed to identify the main drivers of cladoceran species richness build-up and species accumulation patterns in newly created pondscapes. A total of 26 newly created ponds across two newly established pondscapes were surveyed repeatedly (n = 11) for environmental pond variables and cladoceran community characteristics during the first three years after their creation. The study ponds varied in surface area, maximum depth and hydroperiod, ranging from permanent to temporary systems. In total, 16 cladoceran species colonized the ponds within three years. Consistent with previous research, Daphnia obtusa was the first species to colonize ponds in both pondscapes. Macrophyte establishment seems to be the most important local factor influencing species accumulation, with vegetated ponds showing faster accumulation, likely because later-arriving cladoceran taxa are associated with macrophytes. Our observations highlight the role of macrophyte establishment during early pond succession and offer insights for designing resilient pondscapes that support effective freshwater biodiversity build-up.

This study aimed to identify the most important drivers of cladoceran species richness build-up and species accumulation patterns in newly created ponds that collectively form entirely new pondscapes (networks of closely situated ponds in a landscape). A total of 26 newly created ponds across two newly established pondscapes were surveyed repeatedly (n=11) for key environmental pond variables and cladoceran community characteristics during the first three years after the pondscapes’ creation. The study ponds vary in surface area and maximum depth and cover a wide range of hydroperiods, from permanent to temporary systems with only a short hydroperiod. In total, 16 cladoceran species colonized the newly created ponds within the first three years of the pondscapes’ existence. Consistent with previous research, Daphnia obtusa was the first species to colonize ponds in both pondscapes. Macrophyte establishment was the most important local factor influencing the accumulation of cladoceran species over time, with vegetated ponds leading to faster species accumulation, likely because of the close association of chydorid species, Simocephalus vetulus and Ceriodaphnia spp with macrophytes. Our observations highlight the role of the establishment of macrophytes for cladoceran species richness build-up during early pond succession and offer valuable insights for designing resilient pondscapes that support rapid cladoceran species accumulation. The authors have no conflicts of interest to declare.

Fish production in ponds has received less attention in the context of reconciliation between agricultural production and biodiversity conservation. These systems can contain remarkable biodiversity, including rich macrophyte communities. However, management intensification resulted in ecosystem and biodiversity deterioration. The present study capitalizes on two well-studied fish pond regions (Dombes, France, and Midden-Limburg, Belgium) to investigate how fish stock management type affects local and regional macrophyte community characteristics. We used data from macrophyte inventories in a set of ponds representing major management types. Our results reveal that fish stock management strongly affects local macrophyte richness and community composition. Management types with higher fish stock densities had lower local richness and the highest local diversity was found in ponds without fish stocking. Differences in community composition between management types within region were primarily determined by nestedness patterns. Communities in ponds with higher fish densities formed nested subsets of communities in ponds with lower fish densities. Our findings suggest that successfully combining fish production with biodiversity conservation, and enhancing macrophyte diversity in large anthropogenic fish pond systems, may be best achieved with a subset of ponds managed without fish stocking, while others are more intensively managed for fish farming.

BACKGROUND:Host-associated microbiomes play an important role in the ecology and fitness of organisms. Given their significance, it is much debated to what extent these associations are widespread and even obligatory. Such frequent associations are captured by the concept of the core microbiome. The cladoceran Daphnia is a pivotal genus in freshwater ecosystems occupying a central position in the food webs of standing waters. With its unique standing in pelagic waters, Daphnia serves as a key grazer, regulating algal populations and nutrient cycling, making its microbiome essential to understanding ecosystem function and stability. In recent years, Daphnia has become an increasingly popular study system for exploring host‒microbiota interactions. There is, however, limited knowledge on the baseline taxa that consistently inhabit this host and potentially contribute to its fitness. Identifying whether such a host-associated "core microbiome" exists for Daphnia and, if so, which microbial taxa it comprises is important both for enhancing our ecological understanding of this genus and its ecosystem function and for interpreting future experiments. RESULTS:We compiled a dataset on Daphnia magna microbiome based on 12 published studies, comprising gut and whole microbiome samples of both laboratory-cultured and field-grown animals across five countries spanning three continents. To identify core taxa, we employ quantification metrics based on prevalence and a combination of prevalence and relative abundance. Our analysis demonstrates that the D. magna microbiome is highly variable, yet, a consistent association with specific taxa, notably Limnohabitans planktonicus, is observed especially under laboratory conditions. However, this pattern is tempered by the observation that field-grown animals exhibit a more diverse microbiome with a weaker presence of L. planktonicus, challenging its status as a core member. CONCLUSIONS:Our analysis suggests that the D. magna microbiome is defined by its high variability and few conserved associations, with L. planktonicus being the most stable taxon in laboratory settings but not necessarily a core member in natural environments. These findings underscore the need for caution when using laboratory results to interpret natural microbiome compositions and emphasize the need for further research on field-grown animals to better understand the structuring of microbial communities under natural settings.

Biodiversity loss and widespread ecosystem degradation are among the most pressing challenges of our time, requiring urgent action. Yet our understanding of their causes remains limited because prevailing ecological concepts and approaches often overlook the underlying complex interactions of individuals of the same or different species, interacting with each other and with their environment. We propose a paradigm shift in ecological science, moving from simplifying frameworks that use species, population or community averages to an integrative approach that recognizes individual organisms as fundamental agents of ecological change. The urgency of the biodiversity crisis requires such a paradigm shift to advance ecology towards a predictive science by elucidating the causal mechanisms linking individual variation and adaptive behaviour to emergent properties of populations, communities, ecosystems, and ecological interactions with human interventions. Recent advances in computational technologies, sensors, and analytical tools now offer unprecedented opportunities to overcome past challenges and lay the foundation for a truly integrated Individual-Based Global Change Ecology (IBGCE). Unravelling the potential role of individual variability in global change impact analyses will require a systematic combination of empirical, experimental and modelling studies across systems, while taking into account multiple drivers of global change and their interactions. Key priorities include refining theoretical frameworks, developing benchmark models and standardized toolsets, and systematically incorporating individual variation and adaptive behaviour into empirical field work, experiments and predictive models. The emerging synergies between individual-based modelling, big data approaches, and machine learning hold great promise for addressing the inherent complexity of ecosystems. Each step in the development of IBGCE must systematically balance the complexity of the individual perspective with parsimony, computational efficiency, and experimental feasibility. IBGCE aims to unravel and predict the dynamics of biodiversity in the Anthropocene through a comprehensive study of individual organisms, their variability and their interactions. It will provide a critical foundation for considering individual variation and behaviour for future conservation and sustainability management, taking into account individual-to-ecosystem pathways and feedbacks.

Cyanobacteria blooms pose a substantial threat to freshwater systems globally. While zooplankton grazers such as Daphnia can have an important role in suppressing cyanobacteria blooms, cyanobacteria can adversely impact Daphnia fitness and even kill them. Earlier work has shown an evolutionary increase in tolerance to cyanobacteria across years and strong genotype × genotype interactions determining the interaction between Daphnia and the cyanobacterium Microcystis. Here, we test the hypothesis that Daphnia magna can adapt during 1 growing season to changes in dominant strains of Microcystis. Over 2 consecutive years, we collected D. magna clonal lineages and Microcystis strains from a single pond early and late in the growing season and we assessed whether Daphnia survival differed when exposed to Microcystis strains from either the same or a different time point within the growth season. Our findings reveal important Daphnia genotype × Microcystis genotype interactions, with Daphnia survival being higher when exposed to Microcystis from the same time point than when exposed to Microcystis of a different time point. Our results extend earlier findings to variation within 1 single natural system and growth season, and suggest an important impact of rapid (co)evolutionary dynamics shaping the tolerance of zooplankton grazers to cyanobacteria.

Eutrophication is a pervasive threat to freshwater ecosystems, and while the implementation of vegetated terrestrial buffer strips is increasingly promoted as a measure to reduce nutrient runoff into riverine systems, little is known on their effectiveness in protecting ponds in agricultural landscapes. We investigated the effect of buffer strip width on pond nutrient concentrations (TN, TP), the concentration of total suspended solids (TSS) and phytoplankton biomass (CHLa) using data from 34 ponds located on agricultural land in Belgium and Germany. We found a strong negative relation between buffer strip width and the concentrations of TN, TP and TSS in the German set of ponds. While even small buffer strips (5 m) can already be effective, our results also show that larger buffer strips are considerably more effective. In contrast, we did not find an association between buffer strip width and the concentrations of TN, TP and TSS in the Belgian ponds. This could be linked to differences in landscape characteristics, historical eutrophication and pond hydroperiod between both countries. In addition, we did not find evidence for an effect of buffer strips on phytoplankton biomass, which is likely reflecting the fact that, even with buffer strips, nutrient concentrations remained very high in the studied ponds.

Harmful algal blooms (HABs) caused by Prymnesium parvum pose significant threats to aquatic ecosystems, as exemplified by the massive fish kill in the Oder River in 2022. In addition to fish kills, P. parvum can affect zooplankton populations that play a crucial role in top-down control of algae. We measured immobilization of Daphnia magna to compare the toxicity of the P. parvum strain that caused the 2022 Oder fish kill (ODER1, known to produce B-type prymnesins) with two well-studied P. parvum strains, UTEX2797 (known to produce A-type prymnesins), and RCC3427 (known to produce C-type prymnesins). D. magna neonates were exposed to a range of cell concentrations of the three P. parvum strains, and immobility was recorded after 24, 48, and 72 h. Overall, immobilization increased with increasing P. parvum cell concentrations and exposure times for all three strains. The ODER1 strain caused 100% immobilization of D. magna at a cell concentration of 200,000 cells/mL after 72 h. The two other P. parvum strains caused significantly higher immobilization at lower cell concentrations, with 100% immobilization at 25,000 cells/mL after 48 h for UTEX2797 and 10,000 cells/mL after 24 h for RCC3427. Our findings highlight strain-specific toxicity of P. parvum on zooplankton. Identifying the dominant prymnesin type of local P. parvum populations may be crucial to predict toxic bloom effects on zooplankton communities.

For many taxonomic groups, online biodiversity portals used by naturalists and citizen scientists constitute the primary source of distributional information. Over the last decade, site-occupancy models have been advanced as a promising framework to analyse such loosely structured, opportunistically collected datasets. Current approaches often ignore important aspects of the detection process and do not fully capitalise on the information present in these datasets, leaving opportunities for fine-grained spatiotemporal backcasting untouched. We propose a flexible Bayesian spatiotemporal site-occupancy model that aims to mimic the data-generating process that underlies common citizen science datasets sourced from public biodiversity portals, and yields rich biological output. We illustrate the use of the model to a dataset containing over 3M butterfly records in Belgium, collected through the citizen science data portal Observations.be. We show that the proposed approach enables retrospective predictions on the occupancy of species through time and space at high resolution, as well as inference on inter-annual distributional trends, range dynamics, habitat preferences, phenological patterns, detection patterns and observer heterogeneity. The proposed model can be used to increase the value of opportunistically collected data by naturalists and citizen scientists, and can aid the understanding of spatiotemporal dynamics of species for which rigorously collected data are absent or too costly to collect.

Amphibians are commonly occurring inhabitants of most lentic freshwater ecosystems, yet their global populations are in alarming decline. Ponds in particular play a crucial role in supporting amphibian biodiversity. In this study, we identified the main drivers influencing amphibian species richness by conducting a comprehensive ecological characterization in 201 ponds across seven European countries spanning a large latitudinal and longitudinal gradient. The amphibian species richness in each of these ponds was assessed using environmental DNA metabarcoding on water samples. The relative influence of climatic, local abiotic and biotic, and land use variables on variation in species richness across ponds was quantified using boosted regression trees. Our results suggest that local factors, particularly chlorophyll-a concentration, but also pond area and depth, are the main drivers of amphibian richness, together with climatic variables such as annual mean precipitation and temperature. The highest richness was observed in low-nutrient, fishless, intermediate-sized, shallow ponds, located in warmer regions with higher precipitation rates. These potential drivers of amphibian richness should be considered in the planning and implementation of amphibian conservation and management actions.

Recent research has shown that climate change can both induce and modulate the expression of plastic traits but our understanding of the role of phenotypic plasticity as an adaptive response to climate change is limited. In this review, we dissect the mechanisms and impact of phenotypic plasticity as a response to accumulating climatic pressures on the individual, species and community levels. (i) We discuss how plasticity can affect individuals, populations and community dynamics and how climate change can alter the role of plasticity. We hypothesise that some pathways to phenotypic plasticity such as irreversible and anticipatory organismal responses will be reduced under increasing climate change. (ii) We then propose an integrated conceptual framework for studying phenotypic plasticity to advance our understanding of the feedbacks between the different levels of biological organisation. (iii) By formulating as yet unaddressed research questions within and across levels of biological organisation, we aim to instigate new research on phenotypic plasticity and its role in climate change responses.

The persistence of local populations exposed to climate change depends on their adaptive potential and on the ability of local individuals to compete with migrating conspecifics tracking environmental shifts. Modern coexistence theory (MCT) offers a framework for studying such competitive interactions among genotypes. However, MCT often focuses on emerging population-level outcomes, aggregating over the underlying individual-level interactions. We present a cross-scale application of MCT, combining it with an Integral Projection Model (IPM), explicitly connecting individual performance to population-level dynamics. We parameterise our model using experimental data on competing Daphnia genotypes from two latitudes. Consistent with observations, our model shows that higher temperatures increase the likelihood of competitive exclusion of Northern genotypes by Southern genotypes. Moreover, it reveals latitudinal variation in neonate sex ratios as a driver of temperature-dependent evolutionary shifts. By identifying vital rates underlying population-level competitive outcomes, our approach preserves the straightforward theoretical interpretability of MCT, while providing enhanced process-level resolution through IPMs.

Spatial processes shape both ecological dynamics and human decision-making. Here, we propose a unifying framework – Meta-CHANS – that integrates metacommunity ecology into the concept of Coupled Human And Natural Systems (CHANS). We highlight how recent theoretical and methodological advances, especially in species distribution modeling and process inference, allow the identification of dominant metacommunity dynamics and their consequences for biodiversity and ecosystem function. We discuss how coupling between human and natural systems across spatial scales might influence ecosystem processes and properties, and how this can inform a decision-making process using elements of structured decision-making. We demonstrate the applicability of our Meta-CHANS framework with three selected examples from river management, urban green space planning, and invasive species management. We illustrate how local- and landscape-level intervention alternatives might lead to different outcomes in terms of metacommunity processes, emerging metacommunity archetypes, and ecosystem properties, and highlight the potential of Meta-CHANS to bridge ecological theory and applied environmental decision-making.

Artificial light at night (ALAN) is an omnipresent anthropogenic stressor disrupting ecological interactions, potentially driving rapid evolutionary change. However, evidence for genetic adaptation to ALAN remains limited, with ecological responses dominating observed effects. Here, we critically review current evidence for evolution under ALAN and propose that interactions between ecological and evolutionary processes-so-called eco-evolutionary feedbacks-may obscure direct evolutionary signals. We argue for more common-garden experiments to disentangle genetic adaptation from environmentally induced plasticity, for multiple study organisms. Using a conceptual framework of an urban freshwater pond and a key ecological interactor, the water flea Daphnia, we illustrate how ALAN may affect key ecological phenomena, including diel vertical migration, parasite infection, and top-down control of algae, and may impose complex and cascading selection pressures. Recognizing interactions between ecological and evolutionary processes provides new insights on how light pollution can influence ecosystem health and inform conservation strategies in increasingly illuminated environments.

Ponds are key freshwater habitats supporting biodiversity and ecosystem services, yet they remain understudied in the context of land use and climate change. We examined 240 ponds across eight countries (seven in Europe and Uruguay) to assess how internal pond characteristics, surrounding land cover and livestock intensity, seasonal climatic variation, and climate influence nutrient concentrations across spatial and temporal scales. Nutrient concentrations were strongly associated with internal features: shallow ponds and short hydroperiods had higher total nitrogen (TN) and total phosphorus (TP) concentrations, while thermal stratification, typically found in deeper ponds, was associated with higher TN, indicating enhanced internal nutrient recycling. Land use also played a significant role with agricultural intensity increasing nutrient concentration (both TN and TP), whereas forest cover reduced TP. Seasonal variation modulated these patterns, with higher TP concentrations observed in summer, and with dilution effects during wetter and cooler periods, particularly for TN in semi-permanent ponds. These findings underscore the combined influence of physical characteristics, landscape context, and climate variability on nutrient concentrations in ponds and highlight the need for integrated, multi-scale approaches to anticipate the impacts of global climate change effects on these ecologically valuable ecosystems.

Online portals have facilitated collecting extensive biodiversity data by naturalists, offering unprecedented coverage and resolution in space and time. Despite being the most widely available class of biodiversity data, opportunistically collected records have remained largely inaccessible to community ecologists since the imperfect and highly heterogeneous detection process can severely bias inference. We present a novel statistical approach that leverages these datasets by embedding a spatiotemporal joint species distribution model within a flexible site-occupancy framework. Our model addresses variable detection probabilities across visits and species by modelling phenological patterns and by extending the use of latent variables to characterise observer-specific detection and reporting behaviour. We apply our model to an opportunistically collected dataset on lentic odonates, encompassing over 100,000 waterbody visits in Flanders (N-Belgium), to show that the model provides insights into biological communities at high resolution, including phenology, interannual trends, environmental associations and spatiotemporal co-distributional patterns in community composition.

1. A substantial body of research has assessed the relative importance of local and regional factors shaping ecological communities, often using lakes and ponds as model systems. However, little is known about how habitat age can help to explain current community structure. The present study investigates the effect of pond age on zooplankton community composition and diversity in farmland ponds. 2. We used a dataset of > 100 morphologically similar farmland ponds of different ages (recent: 3 years; older: 4-15 years, and old: > 15 years) to analyse the extent to which the diversity and composition of current water flea assemblages (Crustacea; Anomopoda) reflect variation in pond age. 3. Young ponds had lower local species richness than old ponds and their communities were nested within those in ecologically similar old ponds. The presence of macrophytes enhanced local richness by promoting the establishment of additional species, while the presence of fish resulted in community turnover and lower local species richness compared to old ponds without fish. 4. Our results demonstrate that pond age is an important factor determining cladoceran species richness and community composition. Newly created ponds are rapidly colonised by regionally common species, while the colonisation by regionally rare species was more restricted. In older ponds, effective species sorting occurred in response to changes in local environmental conditions associated with the establishment of macrophytes and fish. 5. These findings highlight the need for longer time perspectives in colonisation studies to understand patterns of community succession in newly created habitats.