Restoration Evidence – An Interview with Professor Bill Sutherland

Conservation Evidence is a free, authoritative information resource designed to support decisions about how to maintain and restore global biodiversity. Conservation Evidence assesses the research looking at whether interventions are beneficial or not, summarises evidence from the scientific literature about the effects of conservation interventions, such as methods of habitat or species management, and makes information available through published synopses and a searchable database. In collaboration with the Endangered Landscapes Programme, Conservation Evidence is reviewing and summarising available evidence about restoration interventions. Here we speak with Professor Bill Sutherland to find out more about the collaboration.

What is Conservation Evidence, and why is it important?

Conservation Evidence is a free website which aims to support decisions about how to maintain and restore global biodiversity. We summarise evidence from the scientific literature about the effectiveness of a wide range of conservation interventions, such as methods of habitat or species management. By making make evidence more accessible, we hope to make decision-making by practitioners and policy-makers more effective. Topics currently covered in the searchable online database include the conservation of birds, bats, amphibians, forests and biodiversity on farmland, as well as the control of some invasive species, with several more currently underway.

The idea for Conservation Evidence came from medicine, where for many years evidence-based medicine has informed the decisions that doctors make about healthcare. In conservation, however, a similar approach has been lacking, with policy and practice more often informed by anecdote and personal experience than scientific evidence. There are a number of barriers which prevent conservationists from making decisions based on the scientific evidence, primarily time constraints and the availability and accessibility of scientific papers. Conservation Evidence aims to overcome these barriers by providing freely available, simply written summaries of scientific papers, allowing conservationists to make better informed decisions.

How does landscape and ecosystem restoration differ from ‘conservation’ in general

Because the aims of restoration and more general conservation projects are likely to differ, the monitoring and measures of success may also be different. Conservation projects may aim to enhance overall biodiversity at a site, or increase the abundance of a specific species, whereas restoration programmes often aim to restore an entire ecosystem or habitat to a previous, non-degraded state. This means that restoration projects often assess their success relative to a natural site, or some previously measured baseline, rather than numbers of individuals per se. The complexities of restoring an entire ecosystem mean that monitoring the impacts may also be complicated and incomplete, which may result in difficulties in comparing between different projects and sites.

What are the main challenges and evidence gaps for landscape/ecosystem restoration?

As with most areas of conservation, the evidence for restoration is patchy. For example there are a large number of studies documenting reintroductions of birds to sites where they have been lost, but still the monitoring is often inconsistent and limited.

In cases of habitat restoration, projects are often complex, and involve multiple interventions carried out simultaneously. This can make it difficult to disentangle which aspect of the project may be working or not working effectively. However, we would argue that this means that the need for evidence for the impacts of specific individual interventions, as well as combinations of these, is even more important.

From your work so far, can you draw any general conclusions about the evidence for interventions used for landscape/ecosystem restoration?

It appears that the details of how you carry out a restoration project can be really important, and are often region- or species- specific. For example, restoring wetlands for amphibians was found to be generally effective, but some studies found that the number of species or abundance of amphibians was reduced in restored wetlands compared to natural wetlands, but others did not. Similarly, the use of ploughing to enhance seedling establishment in forests gave mixed effects between studies. It is likely that investigating the details of individual studies can help understand these differences.

And, of course, we still need more evidence for almost all possible interventions!

How will you be helping/working with the Endangered Landscapes Programme?

We are planning to create a new webpage (linked to both the ELP website and the Conservation Evidence website), which will allow people to search summaries of the scientific evidence for restoration interventions. We hope that this will be useful to future restoration projects, large and small, and make it easier for them to identify which management actions are likely to be effective. As part of the ELP we are also adding to our evidence base, by summarising the evidence for the restoration of grasslands.

How can people find out more about Conservation Evidence?

Visit our website,, where you will find

  • our searchable database of conservation interventions,
  • pdfs of our synopses (which summarise the evidence on various different topics)
  • What Works in Conservation (in which experts assess the effectiveness of interventions for all the topics we have covered)

The journal Conservation Evidence, a free-to-publish, open access journal where practitioners can share the results of conservation interventions