Assessing distribution changes of selected native and alien invasive plant species under changing climatic conditions in Nyeri County, Kenya

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 similar to 3318 Km(2) 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 similar to 205% under RCP2.6 and similar to 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 similar to 1% under RCP2.6 to similar to 4.5% under RCP8.5 by 2070 while that of S. campylacanthum was between similar to 50% under RCP2.6 to similar 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.

Automated summary

This study assesses the role of climate change in enhancing bio-invasions in natural environments and provides predictions of potential habitat suitability for five problematic alien and native species under future climate scenarios. The study finds that, considering species dispersal, certain species are expected to have an increase in potential habitats while others may experience minimal habitat losses. However, these species still pose a significant threat to inhabited areas and biodiversity hotspot regions under climate change.