Addressing risks to biodiversity arising from a changing climate: The need for ecosystem restoration in the Tana River Basin, Kenya

Tana River Basin, with parts of the railway line and main road passing through the basin. The railway line continues through the high-potential agricultural land in the north of the basin on to Nairobi. 14% of projected refugia (around 10,500 km2) with 2˚C of warming which has not already been converted to agriculture are at risk from the activities described in the National Spatial Plan (Table 1). Refugia for at least one taxon that are at risk from proposed development are also shown on Fig 4. This includes around 1700 km2 of projected refugia inside protected areas, including the Meru National Park. The greatest threat comes from proposed irrigation areas (9% of the refugia at risk). 31% of projected refugia with 4.5˚C warming, which have not already been converted to agriculture, are threatened by the National Spatial Plan. Again, the greatest area is threatened by proposed irrigation (21% of projected refugia). With 4.5˚C warming, all of the refugia not threatened by irrigation development or already converted to agriculture are only classified as refugia for amphibians (S1 Fig). This suggests that plants, mammals, birds and reptiles could be more at risk from these development plans. Fig 4. Locations of refugia with 2˚C and 4.5˚C warming. Refugia are projected only if 11 or more GCMs agree on their presence for at least one of the five taxa considered in this study. Bars show the percentage of the basin within each of the categories. Grey indicates the percentage of the basin

which is not projected to contain refugia. Protected Areas data was obtained from the World Database of Protected Areas: [44]. https://doi.org/10.1371/journal.pone.0254879.g004 PLOS ONE Risks to Kenya’s biodiversity from climate change PLOS ONE | https://doi.org/10.1371/journal.pone.0254879 July 21, 2021 9 / 25