MODELING HABITAT SUITABILITY FOR AFRICAN ELEPHANTS (Loxodonta africana) AND THEIR PREFERRED FORAGE IN NASALOT-SOUTH TURKANA-KERIO VALLEY ECOSYSTEM, KENYA

Abstract

Understanding the environmental drivers of habitat suitability for African elephants and their preferred forage plants is critical for conservation, particularly under climate change. This study focused on the Nasalot–South Turkana–Kerio Valley ecosystem in Kenya, aiming to model the current and future spatial distribution and abundance of suitable habitats for African elephants and their preferred forage plants. It also analyzed key environmental factors influencing habitat distribution and evaluated the impacts of climate change under Shared Socio-Economic Pathways (SSP) 245 and SSP585 scenarios for 2041–2060 and 2081–2100-time horizons, using the Canadian Earth System Model Version 2 (CanESM2) model from Sixth Phase of the Coupled model Intercomparison Project (CMIP6). Elephant occurrence data were sourced from previous surveys, while preferred forage plant data were systematically collected along 1 km-spaced line transects. Data on climate, topography, vegetation, soil, distance layers, and Land Use/Land Cover (LULC) were obtained from global databases, including World Climate (WorldClim), United States Geological Survey (USGS), Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM), HydroSHEDS, and OpenStreetMap. A Maximum Entropy (MaxEnt) model was employed using spatially independent occurrence data, non-correlated environmental variables, linear and quadratic feature combinations, and regularization multipliers of 1 and 3.5 for elephants and their preferred forage plants, respectively. Model performance was evaluated using the Area Under the Curve (AUC) of the Receiver Operator Curve (ROC) curve. Both models showed strong predictive performance, with mean AUC values of 0.868 ± 0.006 for elephants and 0.883 ± 0.007 for their preferred forage plants. Results indicated that African elephants and their preferred forage plants are highly susceptible to climate change, with habitat suitability and abundance exhibiting notable spatial variability. At present, suitable habitats are limited in extent, with low-suitability areas dominating central regions and highly suitable zones largely restricted to the south. Forage species exhibit similarly low habitat abundance, particularly across central and northern areas. Projections under both SSP245 and SSP585 scenarios indicate a substantial decline in the abundance of suitable habitats, with a pronounced shift toward unsuitability, especially in northern regions, including key protected areas such as Nasalot and South Turkana. Jackknife tests identified precipitation of the coldest quarter (62.5%) and LULC (14.6%) as the main factors influencing elephant habitat suitability, while precipitation seasonality, precipitation of the driest quarter, elevation, and LULC were the primary drivers for forage plant suitability. Climate change was projected to threaten the distribution and survival of both elephants and their forage plants, with suitability shifts varying by scenario and timeframe. These findings highlight the need for adaptive management strategies that incorporate future climate projections to safeguard elephant populations and their forage resources in this vulnerable dryland ecosystem.