Post-fire Influence on Erica Shrubland within the Afroalpine Vegetation: A case study in South of the Bale Mountains National Park, Southeast Ethiopia

Getahun, Mekonnen (2009) Post-fire Influence on Erica Shrubland within the Afroalpine Vegetation: A case study in South of the Bale Mountains National Park, Southeast Ethiopia. Masters thesis, Addis Ababa University.

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Abstract

The aim of the study was to compare variations in size, density, and concentration of the floristic composition, soil seed bank and soil nutrient concentration respectively between recently and previously burnt blocks within the lower and upper boundary of the Erica shrubland community, in the upper Afroalpine vegetation zone of the BMNP, Southeast Ethiopia. A stratified-systematic sampling design was used to collect data on each block, each comprising three quadrats having equal size of 20m by 20m (400m2). Accordingly, a total of twelve quadrats were laid out along two transect lines: one passing through the recently burnt areas and the other one passing through the previously burnt areas; giving four conditions, two on the lower boundary and the other two on the upper boundary on fire-affected Ericaceous species, Erica arborea L., and other associated plant communities such as herbs and grasses including sedges. As a result, variations in species composition and abundance were significant between blocks; species richness was higher on the lower than upper boundary. Differences in species composition and abundance were greater between blocks within the upper than lower boundary after disturbances by fire. A total of 51native species were identified in the study site. Of the total species identified, herbs and grasses dominated the above-ground vegetation cover. Herbaceous and woody plant species accounted 88% and 12% respectively. Alchemilla haumannii Rothm was the single most abundant and frequent species encountered in the study site. Analysis and interpretation of soil seed bank data showed, at least 24 species were identified in the 0 – 9cm soil layer, of which woody plants were unlikely to germinate from seeds even buried deep in the soil bank which may be due to frequent and/o less frequent but intensive fires. The total average number of germinated seedlings ( per meter square) were: 1487 on the lower recently burnt block, 1911 on the lower previously burnt block, 1687 on the upper recently burnt block, and 1961 on the upper previously burnt block for herbs and, 810, 884, 943, and 962 for grasses including sedges in these corresponding blocks stated for herbs. Generally, herbs dominated in average density deeper in the soil bank on the lower boundary, while on the upper boundary, deeper soil layers were dominated by grasses including sedges. In addition, significant variation was observed along similar soil depth layers, except for 5.5 – 6.0cm. In the same token, only few group of individuals under Rosaceae family use soil bank as an alternative means for regeneration, and hence survival in this fire-affected Erica shrubland. Analysis and interpretation of soil nutrient pool showed, significant variation was observed only for soil permanent wilting point, bulk density, and particle density along the 0 – 10cm depth layer, while significant variation was observed solely for soil organic carbon along the 0 – 50cm depth layer. Hence, fire plays a vital role in maintaining species diversity, succession and local carbon balance in the Erica shrubland of the Afroalpine vegetation.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Fire, species composition and abundance, density and concentration
Subjects: G Geography. Anthropology. Recreation > GE Environmental Sciences
Q Science > QK Botany
S Agriculture > SD Forestry
Divisions: Africana
Depositing User: Selom Ghislain
Date Deposited: 25 May 2018 13:18
Last Modified: 25 May 2018 13:18
URI: http://thesisbank.jhia.ac.ke/id/eprint/4110

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