Ecological restoration benefits human well-being but conservation is better
EU-funded researchers in Spain and the UK have found that ecological restoration measures taken in areas where environmental degradation is rife can help reverse global biodiversity losses. The study, published in the journal Science, also showed that conservation efforts are more effective than restoration when ensuring the quality of 'ecosystem services' such as food, drinking water and carbon storage. The work was funded in part by the REFORLAN ('Restoration of forest landscapes for biodiversity conservation and rural development in the drylands of Latin America') project, which was financed with EUR 1.72 million through the 'Specific measures in support of international cooperation' Thematic area of the Sixth Framework Programme (FP6). 'Ecological restoration involves assisting the recovery of an ecosystem that has been degraded, damaged or destroyed, typically as a result of human activities,' the authors explain. But whether such measures actually deliver enhanced biodiversity, improved water quality or increased carbon storage capacity has not been studied in a systematic way. In the current study, led by José M. Rey Benayas of the University of Alcalá in Spain, a team of researchers combined the results of 89 ecological restoration assessments, conducted in several types of ecosystems across the globe, and conducted a meta-analysis of the data. The results of such an analysis are generally considered to be statistically more powerful than a single study carried out with a single set of conditions. The studies chosen for the analysis, while very different from each other, included three important criteria: they all had clearly outlined 'reference' (pristine), degraded and restored sites. They also provided clear measures of biodiversity and ecosystem processes in the systems examined. While each addressed aspects of ecosystem services (e.g. measuring microbial activity, carbon or heavy-metal content of soil or water quality), the meta-analysis brought them together under a single 'eco-service' concept. The analysis showed that ecological restoration increased biodiversity by 44% and improved ecosystem services by 25%. They also demonstrated that restoration activities targeting enhanced biodiversity should also support ecosystem services, particularly in tropical terrestrial areas, which support a high level of biodiversity and are subject to human pressure. Effects of restoration in aquatic systems were found to be the weakest. 'In addition to the improved biodiversity resulting from ecological restoration, our findings show that such restoration also has benefits for ecosystem services,' said Professor Benayas. 'These services can act as an engine of [the] economy and a source of green employment, so our results give policy makers an extra incentive to restore degraded ecosystems.' Crucially, the analysis also showed that in terms of both services and biodiversity, undamaged 'reference' sites were better on average than damaged areas. 'This may be an aspect of time, but it may be an aspect of restoration; [...] on average, it will never quite get as good an outcome as conserving or maintaining a pristine system,' explained James Bullock of the Centre for Ecology and Hydrology in the UK in a Science podcast interview. 'This is a strong message from our study: that restoration has developed strongly over the past few decades as a very important approach to degraded land, but it is not the overall answer,' continued Professor Bullock. 'The answer still is to maintain and conserve pristine systems if we want to have the best possible biodiversity and the best possible ecosystem services.' Professor Bullock cautioned that while restoration can help reverse losses, the new research shows that 'it is critical for human well-being that we conserve pristine habitats and the biodiversity and ecosystem services they provide'.
Spain, United Kingdom