Local and Landscape Level Impacts of Enclosure and Patterns Used by Pastoralist In Shaping Plant Diversity of Rangelands, Eastern Ethiopia

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Date

2018-09-23

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Addis Ababa University

Abstract

The study was done in the rangelands of Ethiopian Somali region in Shinile Woreda. The study was aimed to understand the impact of enclosure at local and landscape level and patterns used by pastoral community in shaping plant diversity of rangelands with the following specific objectives: to identify the effects of patch enclosure and Acacia shade on herbaceous species richness and soil properties; to evaluates the quality of seed and maternal body size of selected plant species within inside enclosure compared with nearby outside; to determine the impact of enclosure on plant diversity and richness at local and regional species pool and to assess the perception and indigenous knowledge of pastoralists in rangeland management. Four enclosures and four open grazing areas were considered for this study. The vegetation and soil surveys, seed collection and measurement of parental body size of selected species were conducted during wet seasons, i.e., from June to September of 2016.Vegetation data were sampled from 300 quadrates (1mx1m) for herbaceous, 300 quadrates (5mx5m) for shrubs and 60 quadrates (20mx20m) for woody species. Herbaceous and soil data were also sampled from 40 quadrates. Plants were collected following standard herbarium technique. All sampled plants were identified at National Herbarium of Addis Ababa University. Soil samples were analyzed for pH, EC, %OC, %OM, available P and exchangeable K at Soil, Plant and Water Analysis Laboratory of Harames University. Six grass species were selected for detailed studies such as seed number, seed weight, height and tiller number. Statistical analyses were carried out by using R and SPSS software. Correlation coefficients and regression analyses were verified. One-way ANOVA and Turkey HSD multiple comparisons were used to perform multiple comparisons. A total of 39 herbaceous and 36 woody species were identified from the study area. Grass species richness was significantly high inside enclosure (P=0.000). Herbaceous species richness were significantly high under Acacia shade (P=0.001). Enclosure has no effect on soil EC, %OC, %OM, P and K (P>0.05). However, only soil pH has significantly increased at inside of enclosure (P=0.000). Plant height has significantly increased inside enclosure for all selected species except for Tragus berteronianus. Tiller number has significantly increased inside enclosure for all species (P<0.023) except for Eragrostis cilianensis. Enclosure also significantly improves seed number and weight of all selected grass species (P=0.000). Acacia shade significantly improves only plant height for all selected grass species. The result of Shannon-Weiner diversity index showed that local species pool were lower in plant diversity than both iv ecological and regional species pool. Unlikely, the species richness within local species pool were higher than both ecological and regional species pool. Shinile Woreda pastoralists have an in-depth knowledge and experience regarding the changes that the rangeland ecosystem has undergone. This knowledge and experience is believed to have profound importance for possible integration of scientific principles and practices for future sound rangeland management system in the region.

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Keywords

Acacia Canopy, Enclosure, Herbaceous Species, Indigenous Knowledge, Pastoralist, Rangeland, Seed Quality, Soil Chemistry, Woody Species

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