Effects of Management Practices and Socio-physical Factors on Perennial Plant Diversity of Agroforestry Systems of Gedeo landscapes, Southern Ethiopia

This study investigates the influence of different agroforestry systems, management practices, and socio-physical factors on plant diversity and richness in Gedeo indigenous agroforestry systems in southern Ethiopia. It analyzed 286 sample plots (10m x 10m), collecting data on both woody and non-woody perennial species. Insights into management practices and socio-physical conditions were gathered through surveys, focus groups, and interviews. A total of 78 plant species were identified in the study area. The Coffee-Fruit-tree system showed the highest species richness (10 species per plot) and the highest Shannon (1.482) and Simpson (0.731) diversity indices. In contrast, the Coffee-Enset-tree and Enset-Tree systems had lower species richness (6 species per plot) and fewer stems (20 to 23 per plot). The study found significant differences in species diversity and abundance across elevations, with highland farms having the lowest values (p < 0.001). Plots tilled once a year showed the highest diversity, richness, and abundance, while those ploughed three times a year had the lowest. Weeding once or twice a year did not significantly affect diversity indices, but weeding three times a year reduced them. Wealthier households had lower perennial plant species richness compared to middle-class and poor households. The prevalence of economically focused plants had a detrimental effect on species diversity and richness (p < 0.001), whereas selective tree removal had a positive impact on both. Additionally, the age of the household head and higher altitudes were associated with lower species diversity and richness (p < 0.001). Increased frequency of tillage and weeding by slashing also led to reductions in species diversity and richness. The distance from home to the main market negatively influenced species diversity and richness (p = 0.004), and altitude had a negative effect on both species richness and diversity.