Homegardens and coffee plantations on Kilimanjaro: Refugium for bryophytes in densely cultivated landscapes

抄録

  Agroforestry integrates trees in agricultural landscapes for socio-economic and ecological benefits. On Kilimanjaro, the agroforestry system of the Chagga homegardens harbours a high diversity of vascular plants and animals. In contrast, the commercial coffee plantations represent a monocultural type of agroforestry and are managed more intensively. The aim of this study is to investigate the bryophyte flora of these differently managed agroforestry systems on Kilimanjaro and to highlight their function for biodiversity and as a refuge for bryophytes. We used 10 of the permanent monitoring plots of the DFG-funded Kili-project, each of 20 × 50 m. We recorded the species separately on the ground, on dead wood, on coffee trees and on trees taller than 2 metres using rope-based canopy access methods from arboriculture. In total we found 68 bryophyte species, which (without the 10 new records) corresponds to 45% of the known bryophyte species of the submontane and colline zone of Kilimanjaro. The strongest correlation for the total number of species per plot was with elevation, followed by land use intensity and mean annual precipitation (all, except land use intensity with a positive trend). Our study shows that homegardens and partly also commercial coffee plantations on Kilimanjaro can serve as refuges for former forest dwellers. This ability to conserve nature is enhanced by less intensive land management without using pesticides. As the market for organic products grows, such ecological management could provide coffee farms with a stable income while protecting their biodiversity.