Modeling the distribution of Festuca abyssinica grass species in East African mountain ecosystems

Abstract

Abstract Festuca abyssinica is a perennial and endemic to Africa. It grows along the mountain ranges of eastern Africa to Zimbabwe, the Tibesti mountains of Chad, the Cameroon highlands, Bioko, and the highlands of Angola. Under warming scenarios, climate change will induce upward species movements. The net movement of species to higher altitudes could lead to the disappearance and decline of species in the lower elevations. Therefore, this study aimed to 1) model the current and predict the future distributions of F. abyssinica as a function of the climate change scenarios, 2) explore the environmental factors causing the shifts in its habitat ranges, and 3) identify the its current and future suitable habitats in the Mountains of East African Countries (Ethiopia, Kenya, Tanzania, and Uganda). The species distribution model analyses were performed for the current (1970–2000) and the future climate (from 2061–2080) periods for two shared socio-economic pathways (SSP), SSP 245 and SSP 585 carbon emission scenarios, with the spatial resolution of 30 seconds. For the future climate data, the global climate model (GCM) HadGEM3-GC31-LL was used from the Coupled Model Intercomparison Project Phase 6 (CMIP6). The baseline bioclimatic data and GCM were downloaded from the WorldClim database. The ensemble modelling was run by using RF, MARS, SVM, and MaxEnt to minimize the errors and enhance the predictive performance of the models. Bootstrap with ten replications was applied to fit the models using the 281 occurrence points and background data (n=281) within the R statistical program (version: 4.4.0). The result of the prediction model showed that, under the SSP245 scenario, the suitable habitat of F. abyssinica decreases by 1.07%. However, under the SSP585 scenario, 40.53% new highly suitable habitats across East African mountains were identified during the years 2061–2080 when compared with the habitat suitability area under the current climate scenario.