Data from: Land use legacy effects on woody vegetation in agricultural landscapes of southwestern Ethiopia
Shumi, Girma et al. (2019), Data from: Land use legacy effects on woody vegetation in agricultural landscapes of southwestern Ethiopia, Dryad, Dataset, https://doi.org/10.5061/dryad.1kd43s5
Aim: Past land use legacy effects – extinction debts and immigration credits – might be particularly pronounced in regions characterized by complex and dynamic landscape change. The aim of this study was to evaluate how current woody plant species distribution, composition and richness related to historical and present land uses. Location: A smallholder farming landscape in southwestern Ethiopia. Methods: We surveyed woody plants in 72 randomly selected 1 ha sites in farmland, and grouped them into forest specialist, generalist and pioneer species. First, we investigated woody plant composition and distribution using non-metric multidimensional scaling. Second, we modelled species richness in response to historical and current distance from the forest edge. Third, we examined diameter class distributions of trees in recently converted versus permanent farmland. Results: Historical distance was a primary driver of woody plant composition and distribution. Generalist and pioneer species richness increased with historical distance. Forest specialists, however, did not respond to historical distance. Only few old individuals of forest specialist species remained in both recently converted and permanent farmlands. Main conclusions: Our findings suggest that any possible extinction debt for forest specialist species in farmland at the landscape scale was rapidly paid off, possibly because farmers cleared large remnant trees. In contrast, we found substantial evidence of immigration credits in farmland for generalist and pioneer species. This suggests that long-established farmland may have unrecognised conservation values, though apparently not for forest specialist species. We suggest that conservation policies in southwestern Ethiopia should recognize not only forests, but also the complementary value of the agricultural mosaic – similarly to the case of European cultural landscapes. A possible future priority could be to better reintegrate forest species in the farmland mosaic.