Dynamic Habitat Disturbance and Ecological Resilience (DyHDER): Modeling Population Responses to Habitat Condition

Understanding how populations respond to spatially heterogeneous habitat disturbance is as critical to conservation as it is challenging. Here, we present a new, free, and open‐source metapopulation model: Dynamic Habitat Disturbance and Ecological Resilience (DyHDER), which incorporates subpopulation habitat condition and connectivity into a population viability analysis framework. Modeling temporally dynamic and spatially explicit habitat disturbance of varying magnitude and duration is accomplished through the use of habitat time‐series data and a mechanistic approach to adjusting subpopulation vital rates. Additionally, DyHDER uses a probabilistic dispersal model driven by site‐specific habitat suitability, density dependence, and directionally dependent connectivity. In the first application of DyHDER, we explore how fragmentation and projected climate change are predicted to impact a well‐studied Bonneville cutthroat trout metapopulation in the Logan River (Utah, USA). The DyHDER model predicts which subpopulations are most susceptible to disturbance, as well as the potential interactions between stressors. Further, the model predicts how populations may be expected to redistribute following disturbance. This information is valuable to conservationists and managers faced with protecting populations of conservation concern across landscapes undergoing changing disturbance regimes. The DyHDER model provides a valuable and generalizable new tool to explore metapopulation resilience to spatially and temporally dynamic stressors for a diverse range of taxa and ecosystems

Refining trait resilience: identifying engineering, ecological, and adaptive facets from extant measures of resilience

The current paper presents a new measure of trait resilience derived from three common mechanisms identified in ecological theory: Engineering, Ecological and Adaptive (EEA) resilience. Exploratory and confirmatory factor analyses of five existing resilience scales suggest that the three trait resilience facets emerge, and can be reduced to a 12-item scale. The conceptualization and value of EEA resilience within the wider trait and well-being psychology is illustrated in terms of differing relationships with adaptive expressions of the traits of the five-factor personality model and the contribution to well-being after controlling for personality and coping, or over time. The current findings suggest that EEA resilience is a useful and parsimonious model and measure of trait resilience that can readily be placed within wider trait psychology and that is found to contribute to individual well-bein

Modèles ecologiques pour l'extrapolation des effets écotoxicologiques enregistrés lors de biotests in situ cheZ Gammarus

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCAInternational audienceEvaluating the effects of chemical contamination on populations and ecological communities still constitutes a challenging necessity in environmental management. However the toxic effects of contaminants are commonly measured by means of organism-level responses. Linking such effects measures with ecological models is a promising way to apprehend population-level impacts. In this way, population models are currently increasingly used in predictive risk assessment procedures, but their use in environmental diagnostic framework remains limited due to their lack of ecological realism. The present study with the crustacean amphipod Gammarus fossarum, a sentinel species in freshwater monitoring, combines a dual field and laboratory experimental approach with a population modelling framework. In this way, we developed an ecologically-relevant periodic matrix population model for Gammarus. This model allowed us to capture the population dynamics in the field, and to understand the particular pattern of demographic sensitivities induced by Gammarus life-history phenology. The model we developed provided a robust population-level assessment of in situ-based effects measures recorded during a biomonitoring program on a French watershed impacted by past mining activities. Thus, our study illustrates the potential of population modelling when seeking to decipher the role of environmental toxic contamination in ecological perturbations

Pharmaceutical pollution of the world's rivers

Environmental exposure to active pharmaceutical ingredients (APIs) can have negative effects on the health of ecosystems and humans. While numerous studies have monitored APIs in rivers, these employ different analytical methods, measure different APIs, and have ignored many of the countries of the world. This makes it difficult to quantify the scale of the problem from a global perspective. Furthermore, comparison of the existing data, generated for different studies/regions/continents, is challenging due to the vast differences between the analytical methodologies employed. Here, we present a global-scale study of API pollution in 258 of the world's rivers, representing the environmental influence of 471.4 million people across 137 geographic regions. Samples were obtained from 1,052 locations in 104 countries (representing all continents and 36 countries not previously studied for API contamination) and analyzed for 61 APIs. Highest cumulative API concentrations were observed in sub-Saharan Africa, south Asia, and South America. The most contaminated sites were in low- to middle-income countries and were associated with areas with poor wastewater and waste management infrastructure and pharmaceutical manufacturing. The most frequently detected APIs were carbamazepine, metformin, and caffeine (a compound also arising from lifestyle use), which were detected at over half of the sites monitored. Concentrations of at least one API at 25.7% of the sampling sites were greater than concentrations considered safe for aquatic organisms, or which are of concern in terms of selection for antimicrobial resistance. Therefore, pharmaceutical pollution poses a global threat to environmental and human health, as well as to delivery of the United Nations Sustainable Development Goals

Intérêt d'un indicateur écotoxicologique pour diagnostiquer et comprendre l'état des milieux aquatiques et aider à la restauration

[Departement_IRSTEA]Eaux [TR1_IRSTEA]BELCACette étude a abordé deux questions essentielles et clés pour mieux comprendre l'impact de la pression chimique sur la toxicité et la vulnérabilité des milieux aquatiques et ainsi aider à mieux définir les stratégies d'aménagement. Si les outils de bio-indication répondent pleinement à leurs objectifs et permettent de caractériser la diversité, le fonctionnement et donc l'état écologique des milieux aquatiques, il est difficile d'établir un lien avec la pression chimique et par conséquent d'en évaluer leur impact sur le milieu. Dans ce travail, l'objectif était d'évaluer si les outils écotoxicologiques, construits autour de l'encagement de gammares pouvaient d'une part, aider à mieux qualifier l'impact toxique de la pression chimique des milieux et d'autre part mettre en évidence une variabilité temporelle de la toxicité. Ces travaux ont mis en évidence et confirmé que le test du taux d'alimentation chez le gammare est un outil très sensible et pertinent pour qualifier les stations et les hiérarchiser entre elles, au regard de leur niveau de contamination. C'est l'outil qui permet de discriminer le plus largement les stations les unes des autres. La mesure de la fécondité, bien qu'elle se soit montrée moins sensible, permet d'identifier les stations pour lesquelles le niveau de contamination n'affecte pas la survie, mais pour autant perturbe une fonction clé dans le maintien des populations. Les mesures de l'activité acétylcholinestérase et de la mue sont spécifiques d'une typologie de contaminants, n'identifiant qu'un faible nombre de stations, ce qui en fait des outils peu pertinents pour hiérarchiser les stations entre elles, comme le montre les résultats obtenus dans ce travail et doivent être proposés dans le cadre d'études spécifiques comme les bassins viticoles et arboricoles. Enfin, ces travaux montrent que la mesure du taux d'alimentation est un marqueur suffisamment sensible et pertinent pour décrire la variabilité de la toxicité des milieux. Il existe peu de travaux et outils permettant de caractériser la toxicité des cours d'eau dans le temps. Ces premiers travaux montrent que la toxicité des milieux varie dans le temps, avec des profils variés selon les stations et la pression chimique plus ou moins ponctuelle

Ecotoxicologie et dynamique de population : utilisation des modèles DEBtox dans une approche de modélisation Leslie

International audienceAlthough the ecological risks of toxic chemicals are usually assessed on the basis of individual responses, such as survival, reproduction or growth, ecotoxicologists are now attempting to assess the impact of environmental pollution on the dynamics of naturally exposed populations. The main issue is how to infer the likely impact on the population of the toxic effects observed at the individual level. Dynamic energy budget in toxicology (DEBtox) is the most user-friendly software currently available to analyze the experimental data obtained in toxicity tests performed on individuals. Because toxic effects are diverse and because the sensitivity of individuals varies considerably depending on life-cycle stage, Leslie models offer a convenient way of predicting toxicant effects on population dynamics. In the present study, we first show how parameter inputs, estimated from individual data using DEBtox, can be coupled using a Leslie matrix population model. Then, using experimental data obtained With Chironomus riparius, we show how the effects of a pesticide (methiocarb) on the population growth rate of a laboratory population can be estimated. Lastly, we perform a complex sensitivity analysis to pinpoint critical age classes within the population for the purposes of the field management of populations

Ecotoxicologie et dynamique de population : utilisation des modèles DEBtox dans une approche de modélisation Leslie

[Departement_IRSTEA]MA [TR1_IRSTEA]QSA / EXPER [Departement_IRSTEA]MA [TR1_IRSTEA]QSA / EXPERInternational audienceAlthough the ecological risks of toxic chemicals are usually assessed on the basis of individual responses, such as survival, reproduction or growth, ecotoxicologists are now attempting to assess the impact of environmental pollution on the dynamics of naturally exposed populations. The main issue is how to infer the likely impact on the population of the toxic effects observed at the individual level. Dynamic energy budget in toxicology (DEBtox) is the most user-friendly software currently available to analyze the experimental data obtained in toxicity tests performed on individuals. Because toxic effects are diverse and because the sensitivity of individuals varies considerably depending on life-cycle stage, Leslie models offer a convenient way of predicting toxicant effects on population dynamics. In the present study, we first show how parameter inputs, estimated from individual data using DEBtox, can be coupled using a Leslie matrix population model. Then, using experimental data obtained With Chironomus riparius, we show how the effects of a pesticide (methiocarb) on the population growth rate of a laboratory population can be estimated. Lastly, we perform a complex sensitivity analysis to pinpoint critical age classes within the population for the purposes of the field management of populations

Ecotoxicology and population dynamics: Using DEBtox models in a Leslie modeling approach

International audienc