Africa’s Important Bird Areas and climate change

Twenty first century climate change could see the ranges of many African bird species moving outside the boundaries of the Important Bird Areas where they are currently found, and where work to conserve them is focused. However, some IBAs are likely to gain species whose ranges currently lie beyond their borders. 

 Spatial pattern of projected percentage ensemble turnover of priority species within Important Bird Areas (IBAs) by 2085. Ensemble turnover of priority species for each individual IBA is calculated as the mean species turnover for the three future climate scenarios (i.e. the three GCMs) for the time period 2085. Absolute percentage turnover for each IBA is placed into one of five classes, with warmer colours representing higher projected turnover

A team of scientists from BirdLife and Durham University, together with colleagues from the University of Copenhagen  and the RSPB (BirdLife in the UK) modelled the potential impacts of climate change on the distributions of 1,608 terrestrial breeding birds in sub-Saharan Africa. They showed that turnover of species in the continent’s network of over 800 Important Bird Areas is likely to be substantial, but the network as a whole should remain relatively robust, providing birds can move between protected areas and suitable prey, habitats etc occur in the newly suitable areas. Around 90% of species are projected to continue to find suitable climate in one or more of the IBAs in which they currently occur.

The degree of species turnover, a measure combining both the potential colonization and extinction of species from an area, is projected to increase as climate change becomes more pronounced. Average projected species turnover in IBAs is 10–13% by 2025, rising to 20–26% by 2085. For 815 species of conservation priority (globally threatened, confined to particular biomes, or with restricted ranges), the average turnover in IBAs is 18–21% by 2025, and 35–45% by 2085.

Of these 815 species of conservation priority, 88–92% occur in one or more sites that are projected to retain suitable climatic conditions for them. Suitable climatic conditions for most of the remaining species will become newly available in one or more sites elsewhere within the network. Only 7–8 species are projected to lose suitable climatic conditions from the current network. 

The range shifts required to reach IBAs with newly suitable climate are substantial in a minority of cases (up to 6,000 km), but far smaller for the majority of species. The average distance is 136 km, meaning species will have to move by 2 km per year on average, in order to keep pace with the changing climate up to 2085. The researchers note, however, that these results are likely to represent a fairly optimistic scenario of potential avian community disruption and substantial adaptive management actions will be required to enhance the resilience of the network – including adding new sites, increasing the extent of some current sites, and managing individual sites for change in the context of the entire network.

Despite the likelihood of significant ecosystem disruption however, this research demonstrates that Important Bird Areas can play a key role in mitigating the worst impacts of climate change on biodiversity.

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