Although protected areas (PAs) are declared to provide sanctuaries for biodiversity, they are increasingly threatened by the synergistic effects of invasive alien species and climate change. Consequently, interventions are required to minimize the impacts of these threats on PAs’ integrity. To inform these interventions in the South African context and under the current climate change scenario, we tested for geographic patterns of alien woody species distribution across the network of 1453 PAs using three alien invasion indices – alien species abundance, invaded area ratio and alien species richness. Our analysis shows that, under current climate change scenario, none of the PAs would be effective in shielding against alien plants and PAs that are geographically close tend to share similar invasion patterns. In addition, PAs that are hotspots of alien species are too geographically clustered but these findings are biome-dependent. Our outlier analysis reveals not only an island of disproportionately-rich PAs in alien species, but also identifies some alien-poor PAs. We suggest that PAs that are hotspots of alien species as well as outliers of disproportionately-rich PAs in alien species should be priority in monitoring and invasion control programmes in the face of climate change.

This dataset was collected as explained below: "To maximize sampling of occurrence data, we combined the SAPIA database and PRECIS database of the National Herbarium in Pretoria (Germishuizen and Meyer 2003; which contains records for more than 900,000 specimens of native and non‐native species distributed across 24,500 taxa from southern Africa). We additionally supplemented these data with sampling locations from the African Centre for DNA Barcoding, through the Toyota Enviro Outreach program (http://toyotaoutreach2012.blogspot.co.za/) and the national invasive DNA barcoding project of the WfW program" (Bezeng et al. 2017).

How was the data processed? "Point data were cleaned to remove records with doubtful or imprecise localities. The maximum number of point records was 5336, for the woolly nightshade (Solanum mauritianum), and the minimum was eight, for the stinging tree (Wigandia urens)" (Bezeng et al. 2017). 

References:

Bezeng, S.B., Van der Bank, M., Yessoufou, K., Daru, B.H. & Davies, T.J. Climate change may reduce the spread of invasive and invading species in South Africa. Ecosphere 8, e01694.

Germishuizen, G., and N. L. Meyer. 2003. Plants of southern Africa: an annotated checklist. Strelitzia 14:1–1231

This paper was also used in Bezeng, S.B., Van der Bank, M., Yessoufou, K., Daru, B.H. & Davies, T.J. Climate change may reduce the spread of invasive and invading species in South Africa. Ecosphere 8, e01694.