A Novel Framework for Predicting Emerging Chemical Stressor Impacts in Complex Ecosystems

Freshwater ecosystems provide critical ecosystem services that underpin human societies and wellbeing: including water purification, carbon capture, and the maintenance of sustainable fisheries. However, these ecosystems are under an increasing array of threats, both in the UK and worldwide, especially from a wide range of new and emerging chemical stressors (e.g. novel antibiotics and pesticides). Freshwater biosciences and applied ecology are under-equipped for dealing with these new threats: the evidence base is lacking, there is often little or no mechanistic understanding, or predictive capacity for anticipating how these novel chemicals will operate in the real world. This is particularly true for the ecosystems of the future that are being reshaped and constructed by climate and other environmental changes.

Our project will address all these shortcomings by taken a radically different approach from the classical biomonitoring and ecotoxicology tools that have dominated for many decades. We aim to unearth the general rules by which emerging chemical stressors operate through, and alter, networks of interacting species - from microbes at the base of the food web, through to apex predators in the fish community at the top. This will involve the development of indicators of both proximate pollution, as the chemical first enters the biological system (commonly as a new food source for microbes), and also of its indirect effects as its impact propagates through the food web. For instance, we will be able to answer questions such as: if a new insecticide wipes out the invertebrates in the middle of the food web, does this trigger blooms of nuisance algae as they are no longer kept in check? To achieve this, we will develop a new suite of methods at the ecosystem level that combine lab and field experiments to detect the causal mechanisms that we currently do not understand. The experiments will be combined with mathematical modelling to predict ecosystem-level impacts. We will address both, contemporary ecosystems that could be under imminent threat from new chemical stressors, and ecosystems of the future that will emerge under different scenarios of land-use and climate change.

This will provide a completely new paradigm in chemical stressor monitoring, based on using first principles to derive a novel means of predicting "ecological surprises" that commonly arise due to the inadequacies of our current simplistic approaches when dealing with the true biocomplexity of natural systems. Our scope is for our approach to serve as a diagnostic tool for management, with research findings, for example, supporting the selection of mitigation options that deliver reduction of ecological effects. This paradigm shift will allow far more robust predictions and therefore more informed management decisions about the freshwaters of the future.

The work will bring together the field of pure and applied ecological science, to the mutual benefit of both sets of disciplines. Our proposal represents the first steps along this path to the more multidisciplinary perspective that is going to be critical for dealing with future threats to our ecosystems - from emerging chemical stressors in freshwaters to the growing list of other environmental threats looming on the horizon. Because the approach is general, it will not only pave the way for the next generation of ecological assessment in freshwaters, but it can also be adapted for applications in marine and terrestrial ecosystems.

Our new predictive framework, which blends data with mathematical models, provides a novel tool for assessing the ecosystem impacts of emerging chemical stressors. This will generate a new approach that can be adapted for use in any ecosystem, and which links to current and future policy demands - including the Water Framework Directive (and its potential post-Brexit replacement) in the immediate future and other more strategic goals, such as those set out in the 25-year Lawton Report to Defra.

The main national beneficiaries of this research among the end-user and stakeholder communities include the major UK environmental, conservation and regulatory agencies (Department of Environment Food & Rural Affairs (DEFRA), Environment Agency (EA), Natural England (NE), Centre for Ecology & Hydrology (CEH), Centre for Environment, Fisheries and Aquaculture Science (CEFAS)), for whom understanding, predicting and mitigating the impacts of stressors in natural ecosystems is an essential remit. We have already engaged in discussion with all these bodies and others (listed in Project Partners) both within the UK and overseas, and they have all expressed strong support for developing the new gene-to-ecosystem approach that we are advocating.

Our approach will arm regulatory bodies with a more realistic assessment of future scenarios, based on solid ecological principles and firm empirical and mechanistic evidence. Moreover, this new research will enable commercial companies to assess the potential range of impacts that could arise in natural systems, which is impossible using the reductionist and/or phenomenological approaches that currently prevail. A range of industrial partners, including several water companies, multinational chemical firms, and environmental consultancies have established strong links with members of our consortium, so we have a clear route to transfer our outputs to the wider world.

As part of our outreach and non-academic activities beyond the academic sphere, we will set up an Stakeholder Group (derived from our industry and policy partners) which will steer us on maximising the project's outreach and influence on policy formulation. We will also use Imperial's Centre for Environmental Policy and the stakeholder networks we have developed over recent aligned projects (e.g., via NERC Biodiversity and Ecosystem Service Sustainability, Macronutrients, Environmental Microbiology and Human Health programmes; Woodward et al Large Grant).

Beyond these focal science-policy areas, our project will resonate with wider concerns about the health and ecological risks associated with emerging chemical and climate change: these are manifested across a wide range of scales, from local Citizen Science groups (such as Action for the River Kennet) to those that are more regional (e.g. the Wildlife Trusts), national (e.g. the Riverfly Partnership), international (e.g. the Freshwater Biological Association and Society for Freshwater Sciences) or global (e.g. the Intergovernmental Platform for Biodiversity and Ecosystem Services) in their reach and remit. All these bodies and many individual private citizens are concerned with conserving sustainable ecosystems, and these are conversations we have regularly at outreach events - such as the annual Imperial Festival, which has a footfall of 10,000s of visitors each year - and with various non-academic partners who are interested in our work. We have a strong track record of engagement that we have fostered over many years (e.g the OPAL initiative at Imperial and numerous policy briefings led by the Grantham Institute and the Centre for Environmental Policy).

Finally, because our approach is flexible and transferable, it offers huge potential to complement and add value to other grants being considered within this call, and if funded, we would engage with the other projects to maximise potential synergies and areas of complementarity.

(see also Pathways to Impact)