Understanding Ecological Complexity in a Chemical Stress Context: A Reflection on Recolonization, Recovery, and Adaptation of Aquatic Populations and Communities

Abstract

Recovery, recolonization, and adaptation in a chemical stress context are processes that regenerate local populations and communities as well as the functions these communities perform. Recolonization, either by species previously present or by new species able to occupy the niches left empty, refers to a metacommunity process with stressed ecosystems benefiting from the dispersal of organisms from other areas. A potential consequence of recolonization is a limited capacity of local populations to adapt to potentially repeating events of chemical stress exposure when their niches have been effectively occupied by the new colonizers or by new genetic lineages of the taxa previously present. Recovery, instead, is an internal process occurring within stressed ecosystems. More specifically, the impact of a stressor on a community benefits less sensitive individuals of a local population as well as less sensitive taxa within a community. Finally, adaptation refers to phenotypic and, sometimes, genetic changes at the individual and population levels, allowing the permanence of individuals of previously existing taxa without necessarily changing the community taxonomic composition (i.e., not replacing sensitive species). Because these processes are usually operating in parallel in nature, though at different degrees, it seems relevant to try to understand their relative importance for the regeneration of community structure and ecosystem functioning after chemical exposure. In the present critical perspective, we employed case studies supporting our understanding of the underlying processes with the hope to provide a theoretical framework to disentangle the relevance of the three processes for the regeneration of a biological community after chemical exposure. Finally, we provide some recommendations to experimentally compare their relative importance so that the net effects of these processes can be used to parameterize risk‐assessment models and inform ecosystem management. Environ Toxicol Chem 2023;00:1–10. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Harnessing Computational Methods to Characterize Chemical Impacts on Biodiversity

“…Without adequate assessment of genetic diversity, chemical impacts cannot be characterized beyond the individual organism level, meaning potential impacts on biodiversity are unknown. Genetic variability is crucial to wildlife conservation, and its evaluation is needed to assess not only individual and population resilience, but also the level of adaptation possible for existing populations with current and changing chemical pressure . However, genetic diversity assessment has received less attention than other levels of biodiversity and is often disconnected from chemical risk assessment.…”

“…Genetic variability is crucial to wildlife conservation, and its evaluation is needed to assess not only individual and population resilience, but also the level of adaptation possible for existing populations with current and changing chemical pressure. 16 However, genetic diversity assessment has received less attention than other levels of biodiversity 17 and is often disconnected from chemical risk assessment. For example, there are numerous research branches related to ecological genetics, including evolutionary genetics, population genetics, and functional genetics, with most fields focusing on the emergence of genetic variants to describe phylogenetic relationships or genetic diversity in the context of ecosystem conservation against stressors without specification.…”

Insights in Pharmaceutical Pollution: The Prospective Role of eDNA Metabarcoding

“…The evaluation of the detrimental impacts of pollutants on ecosystem processes can be conducted through the utilization of experimental systems, such as sediment [220] and stream microcosms or mesocosms [221,222]. In addition, novel approaches exist for evaluating ecological well-being, including stressorspecific indicators like pollution-induced community tolerance (PICT) [223], multivariate diagnostic tools for assessing the responses of microbial communities to pollutants [224], and the SPEcies AT Risk index (SPEAR) for detecting the adverse effects of toxic stress on macroinvertebrate communities [225]. These methods prove to be valuable in assessing ecological health.…”

Ecological Theory and Concepts in Ecotoxicology

“…These authors provide a critical perspective on cross-fertilization and integration among these largely separate fields of research. Bundschuh et al (2023) discuss ecological processes relevant for the development of populations and communities after or during exposure to contaminants. The authors first define recovery, recolonization, and adaptation, and then support these concepts by relevant examples.…”