ENVIRONMENTAL AND HUMAN INFLUENCES ON INDIGENOUS PLANT COMMUNITY STRUCTURE OF EMBOBUT FOREST RESERVE IN ELGEYO MARAKWET COUNTY, KENYA

Abstract

Embobut Forest Reserve is affected by the natural environmental variation and human activities that have not been studied. This study determined the plant species composition, abundance and diversity in relation to environmental variation and human activities at four designated sites in Embobut Forest Reserve. The sites were classified in the form of valley floor, escarpment, upland forest and montane region based on altitude ranges. Based on vegetation sampling, there were 645 plant species belonging to 456 genera and 116 families in the entire basin. Among the plant species recorded, there were 41 trees, 60 shrubs, 7 lianas and 126 herbs in 11 forms belonging to herbaceous plant species. Spatial variations in the plants species was significant (P < 0.05). Trees were most abundant in the valley floor (16) while shrubs in escarpment (28) but were both least abundant in montane region (8) and (11) respectively. Tree species diversity was recorded highest at the montane region (3.15), shrubs at escarpment (3.05), lianas and herbs at valley floor (3.15) and (2.87) respectively. Environmental variables influenced the species composition, abundance and diversity in species-specific patterns. Temperature, rainfall, relative humidity, wind speed and altitude significantly (P < 0.05) affected the various life forms sampled in this ecosystem. However, aspect and slope had negative or no significant effect on different life forms. The most frequent human activities were grazing (25) logging (14) and collection of firewood (10). Important human activities influencing most tree species composition were logging, burning, cultivation and grazing while settlements, cultivation, charcoal burning greatly affected the composition of herbs. All life forms depicted highest species abundance and diversities where there were none or minimum human activities except diversity of herbs. There were 208 useful plant species within the area based on assessment. About 51% of the plant species used by people living around Embobut Forest Reserve were herbs and 23.5% shrubs. The plant species were mostly used for fodder (65.4%), firewood (54.8%) and fencing (53.8%). On the other hand the use of leaf (72.1%), stem (62.5%) and branches (49.0%) was popular in the region. The use value index of the plants species was related to the abundance of the plant species and the more the use value the plant species, the higher was the abundance of the plant species. A strategy for management of Embobut Forest Reserve should focus on the multiple-use conservation approaches where environment and human factor will be at play. Some of the areas within the forest showing signs of relatively little human impacts can be designated for strict conservation so that they may act as repositories of biodiversity and possibly as a source of forest genetic resources, alongside sustainable use of the already exploited forest. Conservation, in order to be effective, must strive to balance the protection of countable objects of diversity and the use of natural processes, the balance which should entail a broad assortment of programs on a variety of spatial and