12th August 2015

What works in conservation

The newly published 'What works in conservation' is a resource which aims to support conservation decision-making by providing an assessment, based on the available scientific evidence, of what works and what does not work in conservation with a worldwide view. The book and associated website summarise scientific evidence relevant to different conservation interventions for a number of different habitats, conservation issues, and species groups, including bats. The section on bats in the book is taken from the synopsis produced by Berthinussen, Richardson and Altringham (2014) where all the important evidence is summarised. This synopsis along with the book is available from www.conservationevidence.com.

How were the ratings of effectiveness assessed?

An expert rating of the 'effectiveness' of these interventions is provided, based on the available evidence. To come up with this assessment, a thorough search of the literature has been carried out to generate a database of relevant evidence for each intervention (available to search online at www.conservationevidence.com). Strict criteria were adhered to in selecting which published studies to include in the database of evidence, as follows:

1) A conservation intervention must have been carried out. 2) The effects of the intervention must have been monitored quantitatively. This means that any studies that use predictive techniques or infer findings on indirect evidence were excluded when assessing the evidence behind conservation interventions although some correlative studies which show relationships between related matters were used. Predicted and inferred studies are however useful in extrapolating when particular interventions could bring conservation benefit and when an intervention has not yet been tested in the manner described above although this information may not be as reliable. Thus important alternative sources of evidence commonly used in generating guidelines and recommending actions are not used in this assessment as its purpose is to provide objective evidence by testing interventions directly.

Evidence related to each intervention was summarised and assessed by panels of experts, to determine the effectiveness of the intervention, the certainty of the evidence and whether the intervention is likely to cause negative side-effects to the species or system of interest. Using these expert assessments, interventions are categorized into one of the following: Beneficial; Likely to be beneficial; Trade-off between benefit and harms; Unknown effectiveness; Unlikely to be beneficial; or Likely to be ineffective or harmful. Any interventions for which published studies adhering to the above criteria could not be found are listed as 'No evidence found (no assessment)'. This does not mean that a particular intervention has no conservation benefit, just that there is no available evidence fitting the above criteria to assess any benefit.

The book should be used in conjunction with the more detailed accounts of the evidence available on the website, when making decisions about which conservation interventions to implement to meet a specific goal.

Limitations to remember when using this bookThere are limitations to this study, summarised in the book introduction, which should be taken into account when reading the book and thinking about particular interventions:

- 'No evidence found' DOES NOT mean that an intervention may not provide any benefit, just that no studies adhering to the strict criteria above were found when assessing the intervention. This however may highlight areas that require further scientific study to directly test and quantify the benefit of particular interventions. In some cases it may be impractical or unethical to test an intervention in compliance with the above criteria. For example, to directly test the intervention 'Legally protect bat hibernation sites in mines from reclamation' in the UK, would require allowing some otherwise legally protected mines to be reclaimed and therefore the bat hibernation sites lost, in order to monitor the impacts of this compared to sites which remain protected. But in other cases conservation methods can be tested and this publication highlights the need for this to happen.

- Worldwide coverage. Some evidence presented and used to assess an intervention may be restricted in geographical scope or in the particular habitats or species involved, and may therefore not be relevant to other situations. A more thorough evaluation of the relevant details in studies presented as evidence would be necessary to determine the appropriateness of the study in providing evidence for the benefits of an intervention for each individual situation.

This book and accompanying website provide an evidence base to search when deciding on the most appropriate conservation actions, offering practitioners an up-to-date source of direct evidence about the benefits and harms of different actions. The categories provided in this book are meant as a guide and a starting point in assessing the effectiveness of conservation interventions. When considering the conservation of bats, BCT recommends that decisions are evidence based but would urge that in addition to the evidence utilised in this publication that other evidence (predictive, correlative or inferential) is also considered for the appropriate species in the appropriate range.