Tropical and subtropical agroecosystems
versão On-line ISSN 1870-0462
TEREFE, B.; LIMENIH, M.; GURE, A. e ANGASSA, A.. Impact of Acacia drepanolobium (an invasive woody species) on gum-resin resources and local livelihood in Borana, Southern Ethiopia. Trop. subtrop. agroecosyt [online]. 2011, vol.14, n.3, pp. 1063-1074. ISSN 1870-0462.
We investigated the impact of Acacia drepanolobium, a species threatening rangeland resources including Gum-resin production and pastoralists' livelihoods in Borana. Data were collected through vegetation surveys, key informant interviews, use of formal questionnaires and focus group discussions. We found a total of 22 woody species in the study area. A. drepanolobium was found to be the most dominant (22%) and abundant (65%) invasive woody species with an importance value index (IVI) of 103. According to our respondents, A. drepanolobium was the first widely expanded woody species followed by Dichrostachys cinerea_and A. mellifera. Eighty seven percent of our respondents ranked A. drepanolobium as the most invading woody species during their life time. Overall, our results demonstrated that the impact of A. drepanolobium had greatly affected the condition of rangeland vegetation. The implication is that the reduction in the capacity of rangelands for livestock grazing could reduce the resilience of local livelihood under changing environmental conditions. Furthermore, pastoralists' perception indicated that the expansion of A. drepanolobium had reduced the survival of Gum-resin producing species. Generally, the shift from cattle based pastoral economy to mixed livestock types could be attributed to the expansion of A. drepanolobium that forced the community to shift their mode of production. We confirmed that A. drepanolobium is an invasive indigenous woody species with multiple effects on the ecology of rangelands and on the livelihood security of pastoral communities.
Palavras-chave : Acacia drepanolobium; Borana; Bush encroachment; Importance value index; Invasiveness; Livelihood security; Rangeland ecology.