Nemomissa, Sileshi (Professor)Johansson, Maria (PhD)Bekele, Tamrat (PhD)Bekele, Firew2019-09-052023-11-042019-09-052023-11-042017-06-05http://etd.aau.edu.et/handle/123456789/18999Effects of Grazing Exclusion on Field Layer Species Composition, Biomass and Selected Properties in Gibe Valley National Park, South-western Ethiopia Firew Bekele Abebe, MSc Thesis Addis Ababa University, 2017 Grazing of domestic livestock is one of the most common land-uses in Sub-Saharan Africa. In this study, the effects of grazing exclusion on field layer biomass, litter moisture content, field layer species composition, soil bulk density and soil volumetric water content, soil organic matter and soil pH were investigated using six permanent grazing exclosures situated along an altitudinal gradient in Gibe river gorge, South-western Ethiopia. Species composition was tested by Adonis test and an indicator species analysis was done. Nested anovas were used to examine the effect of grazing on all other parameters. The results showed that after 1.5 years of livestock exclusion, there was a difference in field layer species composition (p=0.022). The significant indicator species for grazed plots was the common grazing weed Leucas deflexa, whilst the most valuable pasture grass Bothriochloa insculpta was the significant indicator species for plots inside exclosures. Field layer cover, grass cover, number of grass species, field layer maximum and average heights were significantly higher inside exclosures than in grazed plots (p=0.020, p=0.004, p=0.008, p<0.001and p<0.001 respectively). Area cover of bare soil was significantly higher in grazed plots (p<0.001). Exclosures had significantly higher grass biomass and soil volumetric water content (p=0.025 and p=0.017 respectively) than grazed plots. These large differences between exclosures and grazed plots showed the large effect of grazing exclosures in changing the vegetation, in an area with relatively high grazing pressure. Excluding an area here from grazing for 1.5 years did not significantly change the number of species, leaf and wood litter biomass, moisture content of four fine fuel biomass fractions, soil bulk density, organic matter content and pH of both 0-5 and 5-10 cm soil layers. However, results indicate a slightly higher soil organic matter and pH, and slightly lower soil bulk density in exclosure plots compared to grazed plots. This finding indicates that these are variables which could become significantly altered by the fences if the livestock exclusion was run over a longer time period.enAltitudinal GradientBulk DensityFine Fuel BiomassPasture BiodiversitySoil Volumetric Water ContentThesis