Floristic Composition and Diversity of Homegarden Agroforestry Systems in the Lowlands of Tigray, North-Ethiopia

Abstract

To reverse the challenges of land degradation, through improved vegetation composition and access to feed and wood, communities in northern Ethiopia started to establish homegarden agroforestry decades ago. However, there was information gap on the floristic composition and diversity of the homegarden agroforestry systems in northern Ethiopia, particularly in the lowlands of Tigray region. Hence, this study aimed at filling the gap. Fifteen homegarden agroforestry farms from fifteen farming households (One homegarden agroforestry farm from each household) were selected purposely. Floristic composition was calculated by summing all the species recorded in all plots. In addition, Shannon diversity index, richness, and evenness were used to assess the diversity of the land use. Density was computed by summing up all the individuals from all sample plots and translated to hectare base for all the species. Twenty eight (28) woody species which belong to 17 families were recorded on the home-garden Agroforestry. Fabaceae and Combretaceae were found to the most dominant families whereas 10 of the 17 families represented each by only one species. The density of the woody species in the homegarden agroforestry was 201 stems ha-1 from which 56.8% was contributed by Cordia africana, Ziziphus spina-christi and Anogeisus leiocarpus. The Shannon diversity index and evenness of the homegarden farms were 2.52 and 0.75 respectively. In terms of the importance value index (IVI) of the species in the homegarden agroforestry, Cordia africana (64.76%) and Ziziphus spina-christi (45.30%) were the top ranking species. The present study revealed that the homegarden agroforestry systems are comparable to other homegarden agroforestry systems in Ethiopia in terms of floristic composition and diversity. Hence, both governmental and private sectors should play their role for the promotion of homegarden agroforestry systems in the study area, and in areas with similar biophysical and social setup. Moreover, afforestation and reforestation programs have to be continued for those species with low density, frequency and dominance in the study area.