Woody plant diversity in an Afromontane agricultural landscape (Debark District, northern Ethiopia)

Abstract

Woody plants serve a wide range of economic, sociocultural, and ecological functions within traditional farming systems. Conservation of woody plant diversity within agricultural landscapes is therefore critical to farmers’ livelihoods. We studied the conservation status of woody plant species and associated indigenous knowledge of small-holder farming communities in the Debark District of northern Ethiopia. We conducted interviews with 60 informants and ran free-listing, preference ranking and direct matrix ranking exercises to measure the use of woody plants by farming communities. To compare farmers’ ranking of plants with their abundance in the landscape, we measured plant frequencies, densities, and diversity by undertaking a vegetation survey. Compared with 55 woody plants named by farmers during interviews, only 14 species were encountered in the vegetation plot data; most of the remaining species were rare and therefore located by targeted searches. We found relatively low indices of species diversity (H′ = 0.58) and evenness (J′ = 0.21), indicating the low conservation status of most woody plants. Trees and shrubs indigenous to the Debark landscape have been recently replaced by an exotic tree species (Eucalyptus globulus) with a more competitive growth rate, which is valued by farmers as an economic species. The most preferred indigenous tree species (e.g. Olea europaea ssp. cuspidata and Juniperus procera) have become increasingly rare, as reported in interviews and confirmed by direct field observation and vegetation plot data. Households have started planting some indigenous woody species; however, the vast majority of new plantings are E. globulus. Swift coordinated actions are necessary to prevent the rapid replacement of indigenous woody plant diversity by a monoculture of non-native trees. A community-based program for integrated ecological restoration of indigenous woody plant diversity would require support from local government agencies and non-governmental organizations.