Implications of global change for Important Bird Areas in South Africa

The Important Bird Areas (IBAs) network of BirdLife International aims to identify sites
that are essential for the long-term conservation of the world's avifauna. A number of
global change events have the potential to negatively affect, either directly or indirectly,
most bird species, biodiversity in general and associated ecological processes in these
areas identified as IBAs. To assist conservation decisions, I assessed a suite of ten
landscape scale anthropogenic pressures to 115 Important Bird Areas (IBAs) in South
Africa, both those currently placing pressures on IBAs and those that constitute likely
future vulnerability to transformation. These threats are combined with irreplaceability, a
frequently used measure of conservation importance, to identify the suite of IBAs which
are high priority sites for conservation interventions: those with high irreplaceability and
are highly vulnerable to anthropogenic threats. A total of 22 (19%) of the South African
IBAs are highly irreplaceable and are highly vulnerable to at least some of the pressures
assessed. Afforestation, current and potential future patterns of alien plant invasions
affect the largest number of highly irreplaceable IBAs. Only 9% of the area of highly
irreplaceable IBAs is formally protected. A total of 81 IBAs (71%) are less than 5%
degraded or transformed. This result, together with seven highly irreplaceable IBAs
found outside of formally protected areas with lower human densities than expected by
chance provides an ideal opportunity for conservation interventions. However, all the pressures assessed vary geographically, with no discernible systematic pattern that might
assist conservation managers to design effective regional interventions. Furthermore, I
used the newly emerging technique of ensemble forecasting to assess the impact of
climate change on endemic birds in relation to the IBAs network. I used 50 endemic
species, eight bioclimatic envelope models, four climate change models and two methods
of transformation to presence or absence, which essentially creates 2400 projections for
the years 2070-2100. The consensual projection shows that climate change impacts are
very likely to be severe. The majority of species (62%) lose climatically suitable space
and 99% of grid cells show species turnover. Five species lose at least 85% of
climatically suitable space. The current locations of the South African Important Bird
Areas network is very likely ineffective to conserve endemic birds under climate change
along a "business a usual" emissions scenario. Many IBAs show species loss (41%; 47
IBAs) and species turnover (77%; 95 IBAs). However, an irreplaceability analysis
identified mountainous regions in South Africa as irreplaceable refugia for endemic
species, and some of these regions are existing IBAs. These IBAs should receive renewed
conservation attention, as they have the potential to substantially contribute to a flexible
conservation network under realistic scenarios of climate change. Considering all the
global change threats assessed in this study, the Amersfoort-Bethal-Carolina District and
the Grassland Biosphere Reserve (IBA codes: SA018; SA020) are the key IBAs in South
Africa for conservation prioritisation.