The role of area enclosures and fallow age in the restoration of plant diversity in northern Ethiopia

This study investigated the roles played by area enclosures and fallow age in the restoration of plant species richness and soil seed bank species richness in degraded mountain rangelands in northern Ethiopia. Management types (enclosures versus grazed) influenced woody and herbaceous species richness, while fallow age showed no effect on the woody species. Management, age and the doubling of fallow age influenced the herbaceous species richness and species diversity. Management showed no effect on soil seed bank species richness. Fallow age and the doubling of fallow time also showed no influence on the soil seed bank of grass species, but they were influential on the forbs species soil seed bank. The trends for restoration of plant species richness and diversity and grass seed bank in response to fallow age were positive-linear, but they declined when the fallow ages were doubled. The exception was the forbs seed bank showed linear trends when age of restoration was doubled. The data suggest that the restoration of degraded rangelands in the high mountain zones of northern Ethiopia was still in the weedy succession stages. Long-term monitoring will be required to gain an informed understanding of the roles played by area enclosures and fallow age in the restoration of plant biodiversity.