The role of climate change in enhancing bio-invasions in natural environments needs to be assessed to provide baseline information for effective species management and policy formulations. In this study, potential habitat suitability maps were generated through Ecological Niche Modeling for five problematic alien and native species in current and future climate simulations for the periods 2050s and 2070s under RCP2.6, RCP4.5, and RCP8.5 emission scenarios. Projected current binary suitability maps showed that 67%, 40%, 28%, 68%, and 54% of the total study area ~ 3318 Km2 is suitable for C. decapetala, L. camara, O. stricta, S. didymobotrya and S. campylacanthum species, respectively. Assuming unlimited species dispersal, two of these species, C. decapetala and S. didymobotrya, were observed to have consistent gradual increase in potential habitats and no habitat losses under the three RCPs by the end of the 2050 and 2070 future periods. The highest recorded relative potential habitat increase was observed for O. stricta at ~205% under RCP2.6 and ~223% under RCP8.5. Although L. camara and O. stricta were observed to have habitat losses, the losses will be very low as compared to that of S. campylacanthum. L. camara and O. stricta relative habitat losses were predicted to be between ~1% under RCP2.6 to ~4.5% under RCP8.5 by 2070 while that of S. campylacanthum was between ~50% under RCP2.6 to ~68% under RCP8.5 by the year 2070. From this study we conclude that the target study species are expected to remain a big threat to inhabited areas as well as biodiversity hotspot areas especially in the Mt. Kenya and the Aberdare forest and national park reserves under climate change. The information generated through this study can be used to inform policy on prioritizing management of these species and subsequent determination of their absolute distributions within the area.

Changes in climatic conditions increases the risks of native and alien taxa expanding in geographical range and causing habitat transformations. The role of climate change in enhancing bio-invasions in local natural environments need to be assessed to guide on effective species management policy formulations. In this present study, we used species presence records, predictor variables and an ensemble of General Circulation Models data to predict suitable ecological niches for five of the selected invasive plant species within Nyeri County, Kenya. We predicted species distributions under RCP2.6, RCP4.5, and RCP8.5 emission scenarios for the years 2050 and 2070. We analysed species distribution changes to identify invasive species requiring immediate management action. Our analysis indicated that three of the five study species were suitable in ~50% of the study area while the other two were suitable in ~30% under the current climate. Lantana camara L. and Solanum campylacanthum Hochst. ex A.Rich species would experience the largest range shift distance of ~6 – 10km and the largest habitat gain of ~12 – 33% in the future. Caesalpinia decapetala (Roth) Alston, Opuntia stricta (Haw.) Haw. and Senna didymobotrya (Fresen.) H.S. Irwin & Barneby species on the other hand would have a decline in habitat range under future climate change scenarios. Although, S. didymobotrya is considered a native species, it would lose half of its current suitable habitat in the future. Range shift analysis showed all study species would generally shift to the north west direction or towards the Aberdare ranges. From this study we conclude that i nvasive species management programs for smaller geographical areas ought to consider projecting species distributions under climate change scenarios to identify areas with high possible biodiversity changes. This would be important to conservationists when prioritizing management actions of invasive species in the region where data on invasive species is still limited.

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