Refocusing multiple stressor research around the targets and scales of ecological impacts

Abstract

Ecological communities face a variety of environmental and anthropogenic stressors acting simultaneously. Stressor impacts can combine additively or can interact, causing synergistic or antagonistic effects. Our knowledge of when and how interactions arise is limited, as most models and experiments only consider the effect of a small number of non-interacting stressors at one or few scales of ecological organization. This is concerning because it could lead to significant underestimations or overestimations of threats to biodiversity. Furthermore, stressors have been largely classified by their source rather than by the mechanisms and ecological scales at which they act (the target). Here, we argue, first, that a more nuanced classification of stressors by target and ecological scale can generate valuable new insights and hypotheses about stressor interactions. Second, that the predictability of multiple stressor effects, and consistent patterns in their impacts, can be evaluated by examining the distribution of stressor effects across targets and ecological scales. Third, that a variety of existing mechanistic and statistical modelling tools can play an important role in our framework and advance multiple stressor research.

Understanding the combined effects of multiple stressors: A new perspective on a longstanding challenge

“…Assessing, predicting, and managing the combined effects of multiple natural and anthropogenic stressors is therefore a primary management and conservation goal, as reflected in many regulatory frameworks. Because stressors are heterogeneous and can affect individuals, populations, communities, and their habitats, estimating their combined effects is salient in many disciplines, from pharmacology and epidemiology (Groten et al, 2001;Taylor et al, 2016), to toxicology (Altenburger et al, 2013;Hernandez et al, 2019), environmental science, conservation biology, and ecology (Breitburg et al, 1998;Côté et al, 2016;Folt et al, 1999;Orr et al, 2020;Rudd and Fleishman, 2014;Simmons et al, 2021;Vinebrooke et al, 2004).…”

“…In summary, the debate over interactions has limited applied relevance (Côté et al, 2016;Hertzberg and MacDonell, 2002;Schäfer and Piggott, 2018). In contrast, there has been growing cross-disciplinary recognition that a detailed understanding of the mechanisms in which stressor effects combine, from chemical to ecological, provides greater predictive power (Ankley et al, 2010;Hernandez et al, 2019;Hertzberg and MacDonell, 2002;Hooper et al, 2013;Schäfer and Piggott, 2018;Simmons et al, 2021). In pharmacology, pharmacokinetic models are increasingly used to capture the movements of compounds in the body (Cohen Hubal et al, 2019).…”

“…Mechanistic approaches have high predictive power (and therefore wide management applicability), but also high structural uncertainty and concomitant risk of bias from selecting an inappropriate model (Barton et al, 2007;Regan et al, 2002). Chemical, biological and ecological knowledge can be used to describe the pathways linking stressor exposure to potential adverse outcomes at different organisational levels (Simmons et al, 2021). This idea has been formalised in the concept of biological upscaling in conservation physiology (Cooke et al, 2014) and AOPs in ecotoxicology (Ankley et al, 2010).…”

Drivers of Ecological and Evolutionary Disruptions in the Seed Dispersal Process: Research Trends and Biases

“…Quantifying the interactions among these drivers would be critical to avoid overestimating or underestimating threats to seed dispersal. A potential way forward to improve the predictability of multiple anthropogenic stressors could be the application of recently developed modeling frameworks based on the distribution of driver effects across targets and ecological scales (Simmons et al, 2021).…”

Are experiment sample sizes adequate to detect biologically important interactions between multiple stressors?

“…Most, if not all, ecosystems are being impacted by multiple co-occurring stressors (e.g., climate change, invasive species, pollution), which are predominately anthropogenic in origin (Halpern et al 2015;Beauchesne et al 2021). As such, there is an urgent need to document and predict how these stressors (threats, drivers) interact given that they are capable of affecting individuals through to entire ecosystems (Jackson et al 2021;Simmons et al 2021;Sokolova 2021). However, current knowledge of how stressors interact to affect various systems is limited (Hodgson & Halpern 2019;Lemm et al 2021).…”