Effects of Bush Burning on Herbaceous Plant Diversity in the Kainji Lake National Park Buffer Zone, Niger State

Annual bush burning is a widespread land management and livelihood practice in communities bordering Kainji Lake National Park in Niger State, North Central Nigeria, with significant but poorly documented effects on herbaceous plant diversity. This study examined the effects of bush burning on herbaceous plant species richness, diversity, and functional group composition in the park's buffer zone, comparing burned and unburned plots during the post-burn recovery period. Twenty paired plots (10m x 10m) representing burned and adjacent unburned areas were surveyed three months and six months after controlled burns. Species richness, Shannon-Wiener and Simpson diversity indices, and percentage cover of annual grasses, perennial grasses, forbs, and geophytes were recorded at each survey. Results showed that burned plots had significantly lower species richness immediately after burning than unburned plots (mean 12.4 vs. 19.8 species per plot). By six months post-burn, species richness in burned plots increased to 17.2, approaching but not equalling unburned diversity levels. Annual grasses increased dramatically in burned plots (from 8% to 31% cover), while forbs and geophytes showed slower recovery. Perennial grass recovery was most rapid, consistent with their fire-adapted root systems. Shannon-Wiener diversity recovered by approximately 73% of pre-burn values at six months. The study concludes that frequent burning suppresses herbaceous diversity recovery and recommends reducing burn frequency in the buffer zone to every 3 to 4 years to allow adequate community recovery.

Keywords: bush burning, herbaceous plant diversity, Kainji Lake National Park, fire ecology, Niger State