Hasenbein, Nils , Kraemer, Manfred .
Win some, loose some – Ecosystem process shifts in a fragmented habitat.
It has been shown that fragmentation of ecosystems affects various ecosystem processes. A decrease of genetic exchange between plant populations due to fragmentation may accelerate their decline and, subsequently, the loss of biodiversity in disturbed habitats. Reproduction in isolated populations may be limited due to a lack of high-quality pollen being transported between plants, resulting from reduced pollinator visitation rates, reduced pollen load of pollinating animals, and low quality of available pollen. Moreover, pollinators may shift to similar species of the surrounding matrix, reducing visitation frequencies inside the fragments and changing the pollen composition of pollen loads. We investigated if forest fragmentation affects the pollination of Acanthus eminens (Acanthaceae), a shrub growing in Kakamega Forest in Western Kenya, which is affected by anthropogenic disturbance and fragmentation. A. eminens grows in natural clearings and along rivers in rainforest habitats and therefore is limited to the few remaining forest areas in Kenya. Its main pollinators are carpenter bees (Xylocopa). We will present data which show that A. eminens is indeed pollinator limited, and shares pollinators with the closely related Acanthus polystachius, a common plant of hedgerows and forest borders of the surrounding farmland. Our presentation includes an analysis whether the species compete for pollinators, and to what extend interspecific pollen transfer affects the reproduction of A. eminens. Our data provide insight into challenges of conservation of fragmented ecosystems. We take into account not only the decline of ecosystem processes caused by fragmentation, but also the effects of new processes being facilitated by fragmentation, which have rarely been included in studies on fragmentation.
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1 - University of Bielefeld, Biological Collection, Universitaetsstraße 25, Bielefeld, 33615, Germany
2 - University of Bielefeld, Biological Collection, Po Box 100131, Bielefeld, D-33501, Germany
Presentation Type: Oral Paper:Papers for Topics
Location: 553A/Convention Center
Date: Monday, August 2nd, 2010
Time: 2:30 PM