Abstract
Kenya's drylands are under growing pressure from both shifting rainfall patterns and declining soil quality, yet these two problems have rarely been examined together across multiple ecological zones. This study investigated how climate change indicators and soil physicochemical properties combine to shape plant communities across five rangeland counties in Kenya i.e., Turkana, Marsabit, West Pokot, Trans Nzoia, and Baringo. A total of 104 plant species were recorded from 426 quadrats (Trans Nzoia: n = 234; Marsabit/Samburu: n = 102; Turkana: n = 58; West Pokot: n = 32) distributed across six vegetation types. Long-term climate records were sourced from five Kenya Meteorological Department stations spanning 1985 to 2023, and 150 composite soil samples from the 0–30 cm depth were analysed for seven physicochemical variables. Canonical Correspondence Analysis showed that annual rainfall variability (F = 8.17, p < 0.001) and soil electrical conductivity (F = 6.54, p<0.001) were the main drivers of species change across the gradient. A regional warming rate of 0.26 °C per decade (range: 0.18–0.33 °C/decade across sites; n = 426 observation plots) was recorded, coinciding with the loss of palatable grasses and spread of woody shrubs such as Acacia reficiens and Prosopis juliflora. Structural Equation Modelling (RMSEA = 0.060, CFI = 0.97) showed that close to half (45.2%) of the total climate effect on vegetation worked through soil moisture and organic carbon rather than acting on plants directly. These findings can inform county-level early warning systems, invasive species control, and soil-focused land management for Kenya's pastoral communities.
Keywords
References
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