Eco Evidence: using the scientific literature to inform evidence-based decision making in environmental management.

In the face of increasing human-induced pressures on natural environments, managers must balance the needs of environmental and human uses in a transparent and defensible manner. Sound decision making in environmental management relies on understanding causal relationships between environmental stressors and ecological responses. However, causal relations are difficult to demonstrate in natural environments because of the difficulty of performing experiments, natural variability, lack of replication, and the presence of confounding influences. Partly because of this, most environmental management decisions are made using expert opinion. Such decisions can lack transparency. Epidemiologists recognized similar difficulties in ascribing causality in the 1960s, and developed â¿¿causal criteriaâ¿¿ to assess causal relations in epidemiological investigations. Causal criteria analysis builds a case for causality based on the cumulative strength of many individually weak pieces of evidence. There have been several calls to use causal criteria analysis in environmental science, but few case studies exist. This may partly result from the lack of standardized methods and analysis tools (analogous to statistical software). We describe the Eco Evidence software package, which has been developed to facilitate causal criteria analysis in environmental science. It employs the published scientific literature as a previously underused source of evidence for such analyses. The software consists of a web database application â¿¿ the Eco Evidence Database â¿¿ for storing and sharing â¿¿evidence itemsâ¿¿ (the information extracted from individual studies necessary for the causal criteria analysis); and a desktop analysis tool â¿¿ the Eco Evidence Analyser â¿¿ that uses evidence shared via the web application to assess causal hypotheses. The database provides a permanent, online repository for causal evidence, accessible with any web browser. Moreover, it allows users to access evidence items entered by previous users, thereby reducing the burden of extracting evidence from the literature. The analysis tool uses a wizard-style interface to guide users through an 8-step standardized approach to causal criteria analysis specifically designed for use in the environmental sciences. A full report is produced at the end of the assessment, which contains all the information used to reach the conclusion. This maximizes transparency of the assessment, and means that any bias in the review will be detected more easily compared to a traditional literature review. We demonstrate the Eco Evidence approach with an example that investigates the evidence for the question of whether increased base flows and increased frequency of high flow events can reduce the encroachment of terrestrial vegetation into the channels of regulated rivers. Legislative and social imperatives are prompting a move from an experience-based to an evidence-based model of environmental management. This will lead to more transparent and repeatable decisions, and potentially better decisions overall. However, such a major change of practice will not be easily achieved. Tools such as Eco Evidence will facilitate the transformation by assisting managers to use scientific evidence to inform difficult decisions. With the Eco Evidence software now publicly released and freely available, we are turning our attention to facilitating uptake of the method through promotion and training. We expect that early adopters of Eco Evidence will help to drive rapid evolution of the method and software. However, the current version is already sufficiently well-developed to aid environmental science and management.