Effects of Fire, Grazing and Agriculture on Carbon Stocks and Biodiversity in the Ruaha-Katavi Landscape

Abstract

The wildlife corridor between Ruaha and Katavi National Parks is under threat from cultivation and increased fire frequencies. This study evaluated the impacts of protection, fire, and habitat conversion on carbon stocks and biodiversity in the Ruaha-Katavi Landscape. Soil carbon, above-ground woody carbon stocks, herbaceous biomass and insect species richness were determined from 87 plots across a variety of land uses. There were significant differences in carbon stocks among different soil, and land use types (p < 0.001). Sandy soils featured significantly higher woody carbon (p < 0.001) than heavy clay soils. Conversion of woodlands to croplands significantly reduced aboveground woody carbon (p < 0.001) from an average of 72.4 Mg/ha for woodlands compared to 30.9 Mg/ha for croplands. Furthermore, croplands had significantly lower woody carbon than grazed woodland remnants in Open Areas (p = 0.005). Herbaceous plants and Orthoptera species richness did not vary significantly with land use (p > 0.05). Lepidoptera species richness significantly correlated with tree species richness. This study provides some key preliminary information that may justify feasible interventions to slow down conversion of woodlands into croplands to achieve climate-related benefits mainly reduction of greenhouse gas emissions by sequestering carbon in wood and soils.