Abstract booklet - gtö – Society for Tropical Ecology

146 PARALLEL SESSION HALL H IV | ANTRHOPOGENIC INFLUENCESPARALLEL SESSION HALL H IV | ANTHROPOGENIC INFLUENCES147Session: Anthropogenic influencesThursday, 24 February, 12:00, Hall H IVSession: Anthropogenic influencesThursday, 24 February, 12:15, Hall H IVDISENTANGLING SMALL-SCALE VARIABILITY IN TREE GROWTH,HERBIVORE DISTRIBUTION AND HERBIVORE-ANTAGONISTINTERACTIONS IN REFORESTATION PLANTATIONS ON FORMERTROPICAL PASTUREANT DIVERSITY VS. SINGLE SPECIES DOMINANCE IN INDONESIANCOCOA PLANTATIONSArno Wielgoss 1 , Yann Clough 1 , Teja Tscharntke 1 , Brigitte Fiala 2Karsten Mody 1 , Mirco Plath 2 , Judith Riedel 2 , Gisela Brand 2 , HectorBarrios 3 , Catherine Potvin 4 , Silvia Dorn 21Univ.Göttingen -Agroecology, Göttingen, DE, arno.wielgoss@uni-wuerzburg.de,2Univ.Würzburg,Zoology III-Tropical Biology, Würzburg,1ETH Zurich, IPAS, Zurich, CH, karsten.mody@ipw.agrl.ethz.ch, 2 ETH Zurich, IPAS,Applied Entomology, Zurich, CH, 3 Universidad de Panama & Smithsonian TropicalResearch Institute, Panama, PA, 4 Smithsonian Tropical Research Institute, Panama& McGill University, Montreal, CAWith our a large scale and long term ant fauna manipulation experiment incocoa plantations, we study the impacts of ants on pests and diseases in tropicalagroforestry. We compare the possible effects of diverse ant communities andsingle species dominated communities and quantify the total ant ecosystemservices by using ant exclusion plots as zero-control.The 16 study plots at the margins of the Lore-Lindu National Park (Sulawesi,Indonesia) differ in altitude, density and diversity of shadow trees and distanceto the nearest rain forest. Each plot contains four subplots of nine cocoa treesin which we experimentally manipulate the ant communities during two cocoayield seasons in 2010 and 2011 by:a) Ant Exclusion;b) Establishment of the dominant ant Philidris cf. cordata;c) Establ. of Dolichoderus thoracicus;d) ControlWe continuously collect data of yield and incidence of pests and diseases andconduct predation experiments. We examine the abundances and identity ofground and tree dwelling ants using standardized baits and test for possibleeffects of ant species, environmental variables and management on pests anddiseases of cocoa.THURSDAY 12:00 Hall H IVDeforestation has produced vast expanses of degraded lands across CentralAmerica. Reforestation of degraded sites with native timber trees may mitigatedegradation. However, unsuitable environmental conditions and pest insectsoften impair reforestation success.We investigated effects of different planting regimes (tree monoculture,tree mixture and tree mixture protected by insecticides) and of small-scaleenvironmental heterogeneity (1) on establishment and growth of three nativetimber trees, Anacardium excelsum, Cedrela odorata and Tabebuia rosea, (2) ondistribution of associated insect herbivores, and (3) on herbivore-antagonistinteractions.We found effects of planting regimes and small-scale heterogeneity (1) on treegrowth but not on tree survival, (2) on the distribution of key herbivores and onherbivore feeding damage, and (3) on the distribution of herbivore-antagonists.Our studies revealed that small-scale environmental heterogeneity affectstimber tree establishment on former pastures. The impact of insect herbivoreson establishing trees may be alleviated by local measures such as plantingregimes, which suppress herbivores or support herbivore-antagonists.THURSDAY 12:15 Hall H IVgtöSociety for Tropical Ecology | Gesellschaft für Tropenökologie e.V. Status and future of tropical biodiversity | Frankfurt, 21 - 24 February 2011gtö