A new study has provided some of the most robust evidence yet that legal protection is effective at reducing the loss of natural land-cover within sites of high conservation importance. The project, funded by the Cambridge Conservation Initiative (CCI) Collaborative Fund for Conservation, was led by the RSPB and BirdLife Africa Partnership and also involved researchers from the University of Cambridge, the UNEP World Conservation Monitoring Centre (UNEP-WCMC) and the Joint Research Centre of the European Commission.

The CCI study compared rates of change in natural land-cover over a 20-year period across sets of protected and unprotected Important Bird Areas (IBAs) in Africa, which had been matched to ensure that they had similar characteristics. Visual assessment of high resolution satellite imagery was used to make accurate assessments of conversion of all types of land-cover between c. 1990 and c. 2008. The study is an advance on previous work examining the effectiveness of protected areas, which only considered forest loss, single sites, included sites not of conservation importance, or did not control for confounding effects (e.g. accessibility of sites). 

Annual rates of loss of natural land-cover in protected IBAs were found to be less than half of those in IBAs with no legal protection. There was also no evidence of displacement of conversion from within protected areas to their immediate surroundings (leakage). These results suggest that the proposed expansion of the global terrestrial protected area network agreed by the Convention on Biological Diversity in 2010, especially if targeted appropriately, will be an effective means of reducing (but not halting) habitat loss, and so of conserving biodiversity.

As Alison Beresford of RSPB, who worked on the image analysis with George Eshiamwata of BirdLife African Partnership Secretariat in Nairobi, explained, the examination of satellite imagery lent itself well to a collaborative project: “Satellite images of anywhere in the world can be analysed from anywhere in the world. This is appropriate for a collaborative project that involved people in Kenya, Italy and the UK. Each partner brought its own skills and knowledge to the project.”

In addition to papers published in PLOS ONE and Ecological Informatics, a further output of this project was the development of a web-based tool (detailed in the paper in Ecological Informatics and available on the website of the Institute of Environment and Sustainability). The team hope that the tool will have applications in assessing land cover change on a larger scale, too. “We have tracked land cover on IBAs using a simple tool – now we can use such a method for global IBA monitoring,” Alison Beresford added.

For further information about the CCI project ‘Do Protected Areas work? Assessing long-term land-cover change in priority sites for conservation in Africa using remote sensing’ visit the project page.