African IBA network 'robust' in the face of climate change
Twenty first century climate change could see the ranges of many African bird species moving beyond the boundaries of the sites established for their protection, raising the spectre of even higher extinction rates than those currently projected.
However, some sites are also likely to gain species whose ranges currently lie beyond the site’s borders. New research has examined the balance between these effects, and shows that under projected climate change over the next century, the African Important Bird Area (IBA) network will be an essential tool for conserving the region’s breeding species.
A team of scientists from BirdLife, the Universities of Copenhagen and Durham, and the RSPB (BirdLife in the UK), have modeled impacts of climate change on the distributions of terrestrial breeding birds in sub-Saharan African. They have shown that turnover of species in the continent’s IBA network is likely to be substantial, but the network as a whole remains robust under projected climate change. Their paper, Projected impacts of climate change on a continent-wide protected area network, has been published in Ecology Letters.
For 1,608 of the region’s breeding bird species, the team used the current known distribution and various climatic variables to model the current climatic conditions each species favours. These models were then applied to three alternative climate change scenarios to project range shifts, and hence degree of turnover of species within 803 IBAs in the region.
The degree of species turnover is projected to increase as climate change becomes more pronounced towards the end of the century. Average projected species turnover in IBAs is 10-13% by 2025, rising to 20-26% by 2085. For 815 species of conservation priority (those that are globally threatened, restricted to particular biomes or that have restricted-ranges), the average turnover in IBAs is 18-21% by 2025 and 35-45% by 2085.
“Higher turnover among priority species is likely to be because species with small ranges tend to have narrow climatic niches and hence show greater sensitivity to climate change compared with more widespread and generalist species”, said Dr David Hole, now a Visiting Fellow at Durham University and lead author of the paper.
“The IBA network is projected to retain suitable climatic conditions for a reassuringly high proportion of species”. Of the 815 species of conservation priority, 88-92% occur in one or more sites that are projected to retain suitable climatic conditions for them in future. Of those that don’t, suitable climatic conditions will become newly available for most of them in one or more sites elsewhere within the network. Only 7-8 species are projected to require expansion of the network in order to provide suitable climatic conditions.
“The survival of much of the planet’s biodiversity under climate change will depend upon adequate protection for biodiverse ecosystems, the IBAs within them, and support for the people who depend on them" —Dr Stuart Butchart, BirdLife
It remains uncertain to what extent species will be able to shift their ranges in response to changing climate. The range shifts required to reach IBAs with newly suitable climate are substantial in a minority of cases (up to 6,000 km), but are far smaller for the majority of species. The average distance is 136 km, meaning that species will have to move by only 2 km per year by 2085 on average.
Despite the likelihood of significant ecosystem disruption, the paper demonstrates that Important Bird Areas can play a key role in mitigating the worst impacts of climate change on biodiversity.
“Protecting these sites now from ongoing threats such as agricultural expansion, logging and unsustainable hunting is therefore essential”, said Dr Stuart Butchart, BirdLife's Global Research and Indicators Coordinator.
“The survival of much of the planet’s biodiversity under climate change will depend upon adequate protection for biodiverse ecosystems, the IBAs within them, and support for the people who depend on them - so that local communities can participate actively in making their environment more resilient. It is essential that policy leads to adequate protection of IBAs and takes account of the critical role that ecosystems play in helping wildlife and people adapt.”
One example, is the Gola Forest Transboundary Peace Park, uniting existing protected IBAs and encompassing additional forest to provide corridors for the movement of wildlife between them. It protects one of the largest remaining blocks of intact forest in the Upper Guinea Area of West Africa. The forests provide very important ecological services locally, nationally and regionally - they play a key role in building resilience of wildlife and people to adapt to climate change and are also internationally important for carbon sequestration. The establishment of the Peace Park ensures that the long-term conservation of the forests, is secured through national and international partnerships for improved forest governance across the Sierra Leone–Liberia border.
Follow-on work funded by the John D. and Catherine T. MacArthur Foundation is now building on these results to develop an Adaptive Management Framework for Important Bird Areas in the face of climate change. “The BirdLife Africa Partnership is at the cutting edge in terms of planning for conservation in a changing climate”, said Butchart.
Article available at http://www3.interscience.wiley.com/journal/122257297/abstract or from the authors.
Credits: BirdLife, Durham University, RSPB