Investigating cumulative effects across ecological scales

Abstract

Species, habitats, and ecosystems are increasingly exposed to multiple anthropogenic stressors, fueling a rapidly expanding research program to understand the cumulative impacts of these environmental modifications. Since the 1970s, a growing set of methods has been developed through two parallel, sometimes connected, streams of research within the applied and academic realms to assess cumulative effects. Past reviews of cumulative effects assessment (CEA) methods focused on approaches used by practitioners. Academic research has developed several distinct and novel approaches to conducting CEA. Understanding the suite of methods that exist will help practitioners and academics better address various ecological foci (physiological responses, population impacts, ecosystem impacts) and ecological complexities (synergistic effects, impacts across space and time). We reviewed 6 categories of methods (experimental, meta-analysis, single-species modeling, mapping, qualitative modeling, and multispecies modeling) and examined the ability of those methods to address different levels of complexity. We focused on research gaps and emerging priorities. We found that no single method assessed impacts across the 4 ecological foci and 6 ecological complexities considered. We propose that methods can be used in combination to improve understanding such that multimodel inference can provide a suite of comparable outputs, mapping methods can help prioritize localized models or experimental gaps, and future experiments can be paired from the outset with models they will inform.

Uncoupled phytoplankton-bacterioplankton relationship by multiple drivers interacting at different temporal scales in a high-mountain Mediterranean lake

“…heat waves). Changes in these multiple factors may potentially trigger complex interactive effects among them; therefore, it is critical to determine their combined impact, which might be stronger (synergistic effect) or weaker (antagonistic effect) than the sum of their individual effects 3,4 . Besides the net effect on organisms, the magnitude and direction of the interaction of multiple factors might help in comparing organisms' responses and in more fully understanding them 5,6 .…”

Structuring cumulative effects assessments to support regional and local marine management and planning obligations

“…CEA approaches are available that provide explicit guidance to deal with the uncertainty inherent in CEA to derive evidenced risk-based outcomes [49]. Numerous relevant methodologies seek to identify cumulative effects operating at different biological and ecological scales (reviewed in [14]. Furthermore, experimental research into interactions between stressors and receptors continues to provide critical insights into the prevalence of nonlinear responses and system feedbacks [57,58].…”

“…The receptor-led perspective [13] brings into consideration connectivity and varied temporal and spatial scales of pertinent processes, patterns and human activities. Varied ecological scales are involved and numerous scientific approaches are relevant, from laboratory studies to ecosystem models (see Hodgson and Halpern [14] for a review of academic CEA approaches addressing ecological scale). The spectrum of stressors acting on receptors tends to reflect a multitude of human activities, highlighting that cumulative effect questions are situated in coupled social-ecological systems (see Table 1).…”

Moving Beyond Silos in Cumulative Effects Assessment

“…Further, responses can be non-linear (Hunsicker et al, 2016) and can cause cascading effects within ecosystems (Kaplan et al, 2010;Griffith et al, 2012). Though these complicating factors present a profound challenge, there have been substantial developments within the field of cumulative effects assessment to address some of these complexities (Shopley and Fuggle, 1984;Cocklin et al, 1992b;Smit and Spaling, 1995;Duinker et al, 2012;Boyd et al, 2018;Hodgson and Halpern, 2018).…”

“…Multiple methods exist to assess cumulative effects, but each are limited in some way (Hodgson and Halpern, 2018). On the one hand, mapping-based approaches can identify areas or species that are most vulnerable to a high number of co-occurring (often 10 or more) stressors (Halpern et al, 2008;Maxwell et al, 2013).…”