Ecological determinants and risk areas ofStriga hermonthicainfestation in western Kenya under changing climate

Abstract

Striga hermonthica(Del.) Benth is a parasitic weed that is damaging major cereal cropsin sub-Saharan Africa (SSA). AlthoughStrigais recognised as an agricultural scourge,there is limited information available indicating the extent of its growth and spread asimpacted by the changing climate in Kenya. This study investigated the impact of cur-rent climate conditions and projected future (2050) climate change on the infestationofStriga hermonthicain the western Kenya region. Specifically, the study aimed topredictStriga hermonthicahabitat suitability in five counties in the western Kenyaregion through using the maximum entropy (MaxEnt) model and bioclimatic, soil,topographic and land use, and land cover (LULC) variables.Striga hermonthicageolo-cations were collected and collated and ecological niche models were developed todetermine the habitat suitability. The results showed that approximately 1767 km2(10% of the total study area) is currently highly suitable forStriga hermonthicaoccur-rence. The future projections showed a range between 2106 km2(19% of the totalstudy area) and 2712 km2(53% of the total study area) at the minimum carbon(RCP 2.6) and the maximum carbon emission scenarios (RCP 8.5) respectively. Eleva-tion, annual precipitation, LULC, temperature seasonality and soil type were deter-mined to be the most influential ecological predictor variables forStriga hermonthicaestablishment. The study revealed the importance of using climate, soil, topographicand LULC variables when evaluating agricultural production constraints such asStri-ga's prevalence. The methodology used in this study should be tested in otherStrigaaffected areas