Abstract booklet - gtö – Society for Tropical Ecology

166 PARALLEL SESSION HALL H IV THURSDAY LINK FOR SURVIVALPARALLE SESSION THURSDAY H III: LINK FOR SURVIVAL167SPIDER SPECIES RICHNESS IN CACAO AGROFORESTRY SYSTEMS,COMPARING VERTICAL STRATA, LOCAL MANAGEMENT ANDDISTANCE TO FORESTUNDERSTANDING IMPACTS OF FRAGMENTATION AND HUMANDISTURBANCE ON TREE SPECIES COMMUNITY IN TROPICAL FORESTFRAGMENTSSandro Pütz 1 , Jürgen Groeneveld 1 , Luciana F. Alves 2 , Jean PaulMetzger 3 , Andreas Huth 1Kathrin Stenchly 1 , Yann Clough 1 , Teja Tscharntke 1THURSDAY 16:45 Hall H IV1University of Goettingen, Goettingen, DE, stenchly@yahoo.deNaturally shaded cacao agroforestry systems provide various ecological nicheswithin a complex, multistratum habitat. Spiders are abundant and diversein these systems and may be economically important predators, but little isknown on the determinants of spider communities in agroforests. We useddata from twelve differently managed cacao agroforestry systems in Indonesiato investigate how the abundance, diversity and composition of spidercommunities of litter, herb and canopy layer are affected by local management(weeding, leaf litter remove) and landscape context (forest distance). Cacaotree canopies accommodated the most diverse spider assemblage, which waspositively affected by the herbaceous species richness, a stratum-overlappinginfluence. On a community level, we found no effect of forest edge proximity onspider abundance or species richness, but species-specific responses showedthat with distance to forest there seems to be a shift of species dominance infavour of generalists. The results showed an impact of all three spatial scalesand suggesta focus beyond shade management is required to understanddeterminants of spider community in cocoa agroforestry systems.1UFZ Helmholtz Centr.Env.Res, Leipzig, DE, sandro.puetz@ufz.de, 2 Botanic Instituteof Arctic and Alpine Research (INSTAAR), Bolder, Colorado, CO, US, 3 University ofSao Paulo, Department of Ecology, Sao Paulo, BRIncreasing demand for bio fuels may lead to even stronger human land usepressure in the tropics with the consequence of massive habitat destructionand following habitat fragmentation, for example within the Brazilian AtlanticForest (Mata Atlántica), one of the biodiversity hot spots in the world. Alreadyapproximately 92% of the former Atlantic forest has disappeared within the lastfive centuries and the remaining forests are mostly highly fragmented.However, fragmentation processes acting on structure and dynamics of tropicalforest fragments are not the exclusive drivers, low intensive logging may actas factor, too. Combined impacts of different drivers may lead to an increasingcomplexity of the response of different tree species groups (plant functionaltypes, PFTs) and thus challenge our understanding of fragmentation effects ontropical tree species communities on the long-term. Such challenges can ideallybe tackled with simulation models.We present the first simulation study of remnant and secondary tropical forestfragments taking fragmentation processes and human disturbance into account,gaining an improved understanding of how tree species in tropical forestfragments react both to fragmentation and human disturbances. We presentsimulation results analysing different intensity levels of human disturbances incombination with fragmentation processes using the individual based spatiallyexplicit forest growth model FORMIND. We apply FORMIND with a plant functionaltype approach to the Brazilian Atlantic Forest at the study site Caucaia/Ibiuna atthe Plateau of São Paulo.Our results show that shade tolerant species groups will suffer strongly fromthe combined impact, intermediate shade tolerant and shade intolerant speciesgroups show a hump-shaped response at different levels of human disturbanceintensity. A significant fraction of these impacts occur during transient dynamicswithin the first 100 years. The strong impact on shade tolerant species groupsmay have serious consequences for tree species impoverishment and may leadto carbon loss in fragmented tropical forest landscapes both on larger spatial andtemporal scales.THURSDAY 17:00 Hall H IVgtöSociety for Tropical Ecology | Gesellschaft für Tropenökologie e.V. Status and future of tropical biodiversity | Frankfurt, 21 - 24 February 2011gtö