9 May 2011
Study confirms IBAs are priority sites for expansion of protected area network in Africa
By Martin Fowlie
A paper co-authored by senior scientists from BirdLife International and the RSPB (BirdLife in the UK) finds a significant mismatch between the protected area network in Africa, and the key habitats occupied by the continent’s most threatened birds.
Important Bird Areas (IBAs) are shown to be much more effective than current protected areas (PAs) at covering the key habitats. Expanding the protected area network to include unprotected and partially-protected IBAs would improve coverage of the most threatened bird species.
African IBAs cover 2.1 million km2, an area comparable to the extent of African PAs (2.2 million km2). However, PAs in Africa are often sited opportunistically or targeted at charismatic and financially important megafauna, resulting in an inefficient representation of species and habitats within the PA network. Two-thirds of African IBAs support significant populations of globally threatened species.
In the paper, Poor overlap between the distribution of Protected Areas and globally threatened birds in Africa , the authors estimate the Extent of potentially Suitable Habitat (ESH) for each species within its the Extent of Occurrence (EOO). The EOO is the area within which a species is known, inferred or projected to occur.
The analysis considered nine Critically Endangered, 59 Endangered and 89 Vulnerable bird species breeding on mainland Africa and Madagascar. Data on each species’ altitudinal range and habitat associations were taken from BirdLife’s datasets.
ESH estimates were considerably smaller than EOOs for most species, with a reduction in 'commission errors' –assuming a species to be present at sites where it does not in fact occur. Reducing commission errors reduces the danger of overestimating the coverage of species’ ranges by PAs or Important Bird Areas (IBAs).
There has been no previous continental-scale analysis of the efficacy of the PA network at covering the ESH of globally threatened species.
On average, just 14% of threatened species’ ESH fell within PAs. By contrast, an average of 30% of species’ ESH fell within IBAs. However, IBAs that overlapped or fell within PAs were significantly less effective at covering the ESH of threatened birds than those outside the PA network. Within partially-protected IBAs, 36 species appeared to occur only in parts of the IBAs that were not protected, and the proportion of ESH within the protected parts was generally much lower than in the unprotected parts.
Critically Endangered species were particularly poorly covered by the PA network, with an average of just 0.5% of ESH within PAs, compared with 29.2% for IBAs.
“By using the Extent of potentially Suitable Habitat, our study provides stronger evidence for the inadequacy of the current PA network for the conservation of the most threatened species”, said BirdLife's Stuart Butchart.
“It also shows that IBAs are much more effective than PAs at covering ESH. This argues that the PA network in Africa should be expanded to improve coverage of species at the greatest risk of extinction, and that the IBA network provides a useful set of priority sites for achieving this. Within partially-protected IBAs, the unprotected parts appeared to be of disproportionate importance for globally threatened birds, suggesting that extending existing PAs in these areas would be beneficial.”
 Poor overlap between the distribution of Protected Areas and globally threatened birds in Africa, Biological Conservation 14 (2011) 99–107