PARENT SESSION
Poster Session 39: Late Breaking and Newsworthy Posters
Friday, August 12, 8:30 AM - 10:30 AM, Exhibit Hall 220 A-E, Level 2, Palais des congrčs de Montréal

Plant-environment interactions in the Borana Lowlands, Southern Oromia, Ethiopia.

Dalle, Gemedo¹, Isselstein, Johannes², Maass, Brigitte ³, ¹ Forest Genetic Resources Conservation Department, Institute of Biodiversity Conservation, Addis Ababa, Ethiopia² Institute of Agronomy and Plant Breeding, George-August University Göttingen., Goettingen, Germany³ Institute for Crop and Animal Production in the Tropics and Sub-tropics, George- August University Göttingen, Goettingen, Germany

ABSTRACT- Abstract The study was conducted in two districts of the Borana lowlands, southern Oromia, Ethiopia to quantitatively explore relationships between plant species and environmental variables. The distribution of plant species in relation to environmental factors was investigated in a total of 58 plots sized 500 m2. Environmental variables measured per each plot were altitude, slope, and soil texture and soil nutrients. Redundancy Analysis (RDA) and Canonical Correspondence Analysis (CCA) were used to detect patterns of vegetation variation that were explained by the assessed environmental variables. Mean values of density (for woody species) and frequency (for herbaceous species) were used for the analysis. Variability in composition of the plant species that was explained by environmental variables was explored. Environmental variables significantly contributed to the variation in spatial distribution of plant species. Most important environmental factors that significantly contributed to the variations in composition of species were altitude, N and Ca. Furthermore, relationships between environmental variables and species richness and density of woody plants were determined. Density of woody plants was negatively correlated with altitude. Species richness was positively correlated with sand and altitude and, thus, negatively with soil nutrients and clay. It was concluded that the measured environmental variables accounted for the main variation in the composition and distribution of the plant species in the Borana lowlands.

Key words: gradient, Ordination, semi-arid, altitude