TY - JOUR

T1 - Land use legacy effects on woody vegetation in agricultural landscapes of south-western Ethiopia

AU - Shumi, Girma

AU - Schultner, Jannik

AU - Dorresteijn, Ine

AU - Rodrigues, Patrícia

AU - Hanspach, Jan

AU - Hylander, Kristoffer

AU - Senbeta, Feyera

AU - Fischer, Joern

N1 - The study was funded through a European Research Council (ERC) Consolidator Grant to Joern Fischer. We sincerely thank all farmers, and the kebele, woreda, zonal and Oromia regional authorities for their permission and support of our research. We thank field assistants and drivers for their support. We also thank two anonymous referees for constructive suggestions that greatly helped us to further improve our manuscript.

PY - 2018/8/1

Y1 - 2018/8/1

N2 - 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 south-western 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 vs. 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 unrecognized conservation values, although apparently not for forest specialist species. We suggest that conservation policies in south-western Ethiopia should recognize not only forests, but also the complementary value of the agricultural mosaic—similar to the case of European cultural landscapes. A possible future priority could be to better reintegrate forest species in the farmland mosaic.

AB - 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 south-western 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 vs. 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 unrecognized conservation values, although apparently not for forest specialist species. We suggest that conservation policies in south-western Ethiopia should recognize not only forests, but also the complementary value of the agricultural mosaic—similar to the case of European cultural landscapes. A possible future priority could be to better reintegrate forest species in the farmland mosaic.

KW - agricultural mosaic

KW - biodiversity conservation

KW - extinction debt

KW - immigration credit

KW - novel ecosystems

KW - nurse tree effect

KW - Sustainability Science

UR - http://www.scopus.com/inward/record.url?scp=85045107459&partnerID=8YFLogxK

U2 - 10.1111/ddi.12754

DO - 10.1111/ddi.12754

M3 - Journal articles

AN - SCOPUS:85045107459

VL - 24

SP - 1136

EP - 1148

JO - Diversity and Distributions

JF - Diversity and Distributions

SN - 1366-9516

IS - 8

ER -