Floristic Composition ; Structure and Regeneration Status of Plant Species In Sanka Meda Forest; Guna Distrct Arsi Zone of Oromia Region Southeast Etoiopia
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Date
2010-06
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Addis Ababa University
Abstract
This study was conducted on Sanka Meda Forest in Guna district, Arsi Zone,
Oromia National Region in southeast Ethiopia, which is a dry everygreen afromontane type of
forest. The objective of the study was to assess floristic composition, vegetation structure,
regeneration pattern and to make a phytogeographical comparison of the forest under study with
some similar forests in Ethiopia. Systematic sampling method was used to collect vegetation data
from seventy 20m x 20m sapling plots for woody species and five 2m x 2m subplots with in each
main plot for herbaceous plants. The sampling plots were placed at every 200 m intervals along
the nine transect lines laid at 400 m a part. The floristic composition and population structure
data for woody species, DBH > 7cm and height > 2m, sampling (DBH < 7cm and 1 – 2m height)
and all seedlings with a hight < 1m and their regeneration status were recorded in each plot. The
vegetation classification was performed using PC – ORD software package. The quantitative
species diversity, richness and evenness were computed to describe plant diversity in each
community type. Species abundance, cover, and environmental variables (altitude, aspect) were
recorded in each sampling plot. A total of 139 vascular plants and a lichen species belonging to
118 genera 63 families were identified. The Asteraceae family had the highest number of species
with 21 species and 14 genera followed by Lamiaceae with 10 species and 8 genera. Four plant
community types: Croton macrostachyus-Lepidotrichilia volkensii, Maytenus undata, Juniperus
procera and Osyris quadripartita-Budleja davidii were recognized. Jaccard’s similarity
coefficients were below 0.5 for all communities, indicating the prevalance of low similarities
among the communities. Thus, all the communities identified are important interms of floristic
diversity and sensitive from conservation point of view.Woody species densities for mature
individuals were 1060.71 stems ha-1, 416.50 stems ha-1 for saplings and 734.64 stems ha-1 for
seedlings. The basal area of the forest was 34.70m2 ha-1. The floristic composition species were
priorized for conservation using population structure, important value index and rejuvenation as
criteria. The population structure and their regeneration behavior in the forest revealed that there
is a need for conservation priority for woody plant species with poor regeneration status. The
prevailing of strong anthropogenic disturbances in the area implies the need for its immediate
conservation action in order to ensure the sustainable utilization of the forest.
Keywords /Phrases: Afromontane forest, floristic composition, plant community, population
structure, phytogeographical comparison, regeneration
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Keywords
Afromontane forest, floristic composition, plant community, population structure, phytogeographical comparison, regeneration.