Das Projekt "Amphikarpie als besonderer Reproduktionsmechanismus bei der tropischen Weideleguminose Centrosema rotundifolium und ihre Beeinflussung durch Mensch und Umwelt auf sandigen Savannenboeden" wird vom Umweltbundesamt gefördert und von Universität Hohenheim, Fakultät III Agrarwissenschaften I, Institut für Pflanzenproduktion und Agrarökologie in den Tropen und Subtropen, Fachgebiet Biodiversität und Landrehabilitation in den Tropen und Subtropen durchgeführt. Centrosema rotundifolium is an amphicarpic wild legume whose potential as pasture species on acid soils of low fertility in the semi-arid to dry-subhumid tropics has been recognised only recently. Amphicarpy, i.e. the ability of the same plant to produce both above- and below-ground seeds, contributes to the regeneration potential of plants from the soil seed bank and thus to the persistence of a plant population in a pasture. Little is so far known concerning the mechanism of amphicarpy in a perennial plant and the effect of environmental factors on the balance between below-ground and above-ground reproduction. In the project, the influence of various environmental stress factors on the resource allocation is investigated on a sandy soil of low fertility in East Venezuela, a site that is representative for neotropical savanna regions. The factors under study are intraspecific competition (plant density), interspecific competition (associated grasses), intensity of defoliation (forage utilisation), fire and fertilization.