Important Bird Area (IBA) networks can support a high percentage of some populations and are particularly important for migratory bird species. Through the ‘Wings Over Wetlands’ Project IBA networks have been assessed for their coverage of 300 waterbird species and efforts are being made to improve the integrity of these networks by filling the gaps identified.
Networks of Important Bird Areas (IBAs) can make an important contribution to conserving birds and other biodiversity. Site networks are particularly important for migratory species, as individuals may use many different sites, often separated by thousands of kilometres, at different stages of their annual cycle. For migratory species it is therefore particularly important to establish how well the network of IBAs may be functioning and take appropriate action to try to fill any gaps.
BirdLife International and Wetlands International are working closely together on the ‘Wings Over Wetlands’(WOW) Project. Through WOW, critical networks of sites are being identified in the area of the African–Eurasian Waterbird Agreement (AEWA) for populations of 300 waterbird species, many of which are migratory. In order to assess whether the IBA network is adequate to support each population during both breeding and non-breeding seasons, the average number of individuals recorded in the whole IBA network during each season is compared with the total size of the population (estimated in Delany and Scott 2006). Ignoring those waterbird species for which no population data are available and those for which a site-based approach is inappropriate (because they are non-congregatory at that stage of their annual cycle), during the breeding season about 30% of populations had good or very good coverage by the IBA network (see figure), while over half of the populations considered had low coverage. During the non-breeding season, when many waterbird species are more congregatory, coverage was higher, with over half of populations having good or very good coverage by the IBA network, while about one third of populations had low coverage.
This analysis demonstrates how effective the IBA approach can be, often capturing a large proportion of the total population at relatively few key sites. However, it also illustrates the importance of regularly reviewing IBA networks and the need for improving the network for some populations. Surveys are currently being carried out through the WOW Project to identify more critical sites for those populations currently less well covered by the IBA network.
Related Case Studies in other sections
BirdLife International (2008) A network of critical sites for migratory waterbirds is being identified across Africa and Eurasia. Presented as part of the BirdLife State of the world's birds website. Available from: http://birdlife.org/datazone/sowb/casestudy/101. Checked: 24/08/2016