A new study, published online by Nature this week, has concluded that managing the areas surrounded protected sites is as important as regulating the activities that take place inside, if biodiversity in tropical forest areas is to be conserved. The research, led by William F. Laurance at the James Cook University in Australia and involving over 100 collaborating authors, assessed the efficacy of 60 protected areas across Asia, America and Africa. Half of the reserves were deemed by the research team to not be performing ‘effectively or passably’ in safeguarding biodiversity.
Laurance et al. insist however that they are not aiming through the study to diminish the importance of protected areas as conservation tools. Instead they aim to highlight the challenges facing protected areas, so that these can be mitigated. Improving our understanding of the pressures impinging upon protected areas and how these can be ameliorated is fundamental to the success of meeting target number 11 under the Aichi Biodiversity Targets agreed by the signatories to the Convention on Biological Diversity in Nagoya, Japan, in 2010:
‘By 2020 at least 17% of terrestrial and inland waters and 10% of coastal and marine areas, especially areas of particular importance for biodiversity and ecosystem services, are conserved through effectively and equitably managed, ecologically representative and well connected systems of protected areas and other effective area-based conservation measures and integrated into the wider landscapes and seascapes.’
According to a Nature editorial commenting on the research, assessments of biodiversity and ecosystem services to date have been hampered by piecemeal data collection and incomparable methodologies, a function of funding constraints and the difficulties of assessing complex systems. Laurance et al’s analysis therefore marks a significant achievement in filling data and knowledge gaps with respect to tropical forest protected sites.
The researchers carried out 262 interviews with field biologists and environmental scientists, with each asked to complete a 10-page questionnaire. This allowed the team to compile a dataset assessing 20 – 30 years of changes to 31 functional groups of species and on 21 potential drivers of environmental change, for 60 protected areas. The potential drivers of change assessed included road building, hunting and forest product extraction.The researchers claim that data have to date been unavailable for such a sufficiently large and representative sample of reserves.
Laurance et al found that across the 60 reserves there was an alarming ‘erosion of biodiversity that is often widespread taxonomically and functionally’, with biodiversity declines in approximately half of the sites. Eighty five per cent of reserves had experienced declines in the forest cover surrounding the sites, with only two per cent of sites seeing an increase in the adjacent forest cover. The researchers conclude that environmental changes such as these outside the reserves were nearly as important as those inside in determining the state of biodiversity within the protected areas.
The papers’ authors suggest that the best strategy for maintaining biodiversity within protected areas in the tropics is to protect them against major proximate threats, particularly from over-harvesting and habitat destruction. Furthermore they recommend the creation and maintenance of sizeable buffer zones around the protected areas, with substantial connections preserved or enhanced to other forested areas. Finally, local communities must be engaged in the conservation of protected areas and should be encouraged to practice low impact land use in areas surrounding reserves.