Abstract

This study examined plant species diversity on marginal and degraded land earmarked for cultivation of Jatropha curcas. A rapid biodiversity assessment of plant species was conducted using visual encounter survey on patches of degraded fallow land and uncultivated marginal areas within commercial and subsistence agricultural landscapes. Measures of species diversity and richness were assessed using Shannon-Wiener Index (H´) and Simpson’s (D´) indices to assess the effect of intensified cultivation on biodiversity. Results indicate that cultivation and intensified farming significantly influenced floristic composition within agricultural landscapes. Fallow areas were floristically rich in herbaceous plants that are adapted to frequently disturbed sites but poor in trees as opposed to uncultivated areas. Uncultivated areas recorded some endangered species including high value Pterocarpus angolensis. J. curcas cultivation should concentrate on degraded fallow areas as they contain species that are adapted to frequent disturbance while uncultivated areas within agricultural landscapes that have higher potential for conservation of indigenous woody species should be spared as village conservation sites.

Key words: Jatropha curcas, species diversity, village conservation areas.