A framework for predicting impacts on ecosystem services from (sub)organismal responses to chemicals

Abstract

Abstract-Protection of ecosystem services is increasingly emphasized as a risk-assessment goal, but there are wide gaps between current ecological risk-assessment endpoints and potential effects on services provided by ecosystems. The authors present a framework that links common ecotoxicological endpoints to chemical impacts on populations and communities and the ecosystem services that they provide. This framework builds on considerable advances in mechanistic effects models designed to span multiple levels of biological organization and account for various types of biological interactions and feedbacks. For illustration, the authors introduce 2 case studies that employ well-developed and validated mechanistic effects models: the inSTREAM individual-based model for fish populations and the AQUATOX ecosystem model. They also show how dynamic energy budget theory can provide a common currency for interpreting organism-level toxicity. They suggest that a framework based on mechanistic models that predict impacts on ecosystem services resulting from chemical exposure, combined with economic valuation, can provide a useful approach for informing environmental management. The authors highlight the potential benefits of using this framework as well as the challenges that will need to be addressed in future work. Environ Toxicol Chem 2017;36:845-859. # 2017 SETAC Keywords-Ecological production function; Ecological risk assessment; Ecosystem service; Environmental management; Mechanistic effects model Challenges for Ecological Risk Assessment and ManagementThe primary goal of ecological risk assessment (ERA) of chemicals is to provide defensible science-based support for environmental management decisions. This involves making explicit connections between impacts on the benefits derived by people from ecosystems (so-called ecosystem services [1]) and the costs of managing the causes of those impacts. At the core of this approach is the need for relevant chemical exposure-response relationships. However, current ERA approaches often fall short in these regards because methods In This Issue: ET&C FOCUSFocus articles are part of a regular series intended to sharpen understanding of current and emerging topics of interest to the scientific community. for estimating and integrating exposure and effects are often based on overly simplistic assumptions [2,3]. For example, measures of organism-level toxicity (e.g., 50% effect concentrations) are used as indicators of population-level impacts of chemicals. A primary concern is that the kinds of information collected to support ERAs are far removed from the kinds of ecological entities (e.g., species or habitats) that are the targets of protection, which themselves are often only vaguely defined in legislation (e.g., European pesticides legislation refers to "no unacceptable effects on the environment"). In practice, protection goals for ecological systems are (implicitly or explicitly) often at the population, community, or ecosystem level (e.g., persistence or abundance of a p...

When things don't add up: quantifying impacts of multiple stressors from individual metabolism to ecosystem processing

“…Empirical data are most often collected at the level of individual organisms or simplified communities, but we typically aim to manage higher levels of biological organisation, such as populations, communities and ecosystem services (Forbes et al . ). Assessing impacts on populations based on individual‐level responses can result in errors because of many compensatory or depensatory processes and feedbacks across levels of organisation.…”

Incorporating Suborganismal Processes into Dynamic Energy Budget Models for Ecological Risk Assessment

“…Thus, DEB theory can serve as a pivotal framework for building process-based models that link molecular-, cellular-, and tissue-level responses to apical endpoints, such as survival, growth, and reproduction (Murphy et al 2018), and subsequently to those at higher levels of ecological organization (Martin et al 2013a,b;Forbes et al 2017;Gergs et al 2014Gergs et al , 2016. The life cycle of an individual is the primary focus, from which sub-and supraorganismic levels are considered.…”

How do we take the pulse of an aquatic ecosystem? Current and historical approaches to measuring ecosystem integrity

“…Nevertheless, toxicological risk assessments are primarily based on dose–response principles, and on an ecosystem level this can be complex. Significant strides are being made to develop tools (e.g., ecological models) to try and connect organism response to ecosystem services (Forbes et al ). However, current ecosystem‐level risk assessment strategies more often emphasize evaluating changes in ecosystem structure and biological integrity (compared with a reference) and determining how these changes result from anthropogenic influence or contaminant input.…”

“…Mechanistic effect models (MEMs) are dynamic ecotoxicological models developed and applied to quantify the impacts of chemical contaminants on individuals, populations, and/or ecosystems. By taking into account factors such as species’ life histories, interactions, constraints, and feedback processes, MEMs can be effectively used to extrapolate the impacts of xenobiotics across levels of biological organization (Forbes et al ; Galic and Forbes ). Although MEMs have been applied in ecotoxicology for decades (O'Neill et al ), they have recently garnered the attention of scientific and regulatory agencies because of their potential to make ecotoxicological risk assessments more ecologically relevant (Grimm and Martin ).…”