Abstract booklet - gtö – Society for Tropical Ecology

234 SCIENTIFIC POSTER SESSION | FOYERSCIENTIFIC POSTER SESSION | FOYER235WEDNESDAY | FOYERTopic: The Andean biodiversity hotspot and its future: biodiversity, ecosystemfunctioning and ecosystem services under environmental changeCOMPETITION-GROWTH-RELATIONSHIP OF CEDRELA MONTANA(MELIACEAE) IN SOUTHERN ECUADOR IN A NATURAL FORESTMANAGEMENT EXPERIMENTSusanne Spannl 1 , Achim Bräuning 1 , Franziska Volland-Voigt 1 , SvenGünter 21Institute of Geography, Erlangen, DE, susi.spannl@web.de, 2 Technical Universityof Munich, Institute of Silviculture, Freising, DEOn the grounds of the dramatic loss of forest areas in Ecuador and the ensuingdecrease of economic high quality timber species, it is mandatory to developconcepts of sustainable forest management to counteract these devastativetendencies. In the protected area of the Reserva Biológica San Francisco(RBSF), Ecuador, the DFG Research Unit 816 is trying to address this problemand to foster indigenous valuable species of trees with the help of silviculturaltreatments. The application of ‘Improvement Felling’ (felling of the strongestcompetitor) was an attempt in a natural forest management experiment toachieve a positive influence on the radial growth of high quality timber species.On the one hand, competition of the surrounding trees should be lessened bythis intervention, and on the other hand the fight for light was supposed to beminimized; both can be propitious for growth.We studied the high quality timber species Cedrela montana and the effects of‘Improvement Felling” on competition-growth relationships. For this purpose,38 individual trees of C. montana were examined in two catchment areas. Thestrongest competitor of each of 20 target trees was felled. The remaining 18trees (reference trees) of the total 38 served as a comparative group, since nofellings were exercised. The competitive pressure on C. montana by surroundingtrees was quantified by means of the HEGYI– index. The estimation of lightabsorption and the fight for light were based on the DAWKINS-classification.In order to measure the effects on the annual radial growth, radial mean ringwidthcurves were measured. In addition, the age of the trees was calculated toconsider possible age effects.The results show that despite the enhanced consumption of light and thereduced pressure of competitors on target trees, the latter grew less thantheir comparative group. However, the preliminary results do not allow theconclusion that the measures of the experiment have negative effects ongrowth of the target trees. In contrast to C. montana, other tree species showedpositive growth reactions after removing competitors. Thus, C. montana mightbelong to a group of species showing a delayed positive reaction.Topic: Ecological networks and ecosystem functioningCHARACTERIZATION OF THE ORAL MICROBIOTA OF FRUGIVOROUSBATS IN THE NEOTROPICSBenjamin Stegmann 1 , Insa Wagner 1 , Peter Dürre 1 , Elisabeth K.V. Kalko 11Universität Ulm, Ulm, DE, benjamin.stegmann@uni-ulm.de, 2 SmithsonianTropical Research Institute, Balboa, PanamaDental caries is in today’s modern human society one of the most widespreaddiseases. It affects humans and most mammal species as well. Although thereare many studies about dental decay in humans and in animal models, thecomplex microbiological and environmental interactions which lead to dentalcaries remain little known. Most investigations of dental caries have focused onanimal models where artificial diets or inoculation of cariogenic bacterial strainsare used to induce tooth decay. However, it is essential to also understand thedevelopment of dental caries under natural conditions. Our study combinesobservations and examinations of the dental status of the frugivorous bat,Artibeus jamaicensis (Phyllostomidae) in the field and subsequent molecularcharacterization of the microbiota in its oral cavity. The bats showed a surprisinglylow incidence of tooth decay although their food contains a high amount ofcarbohydrates that can be metabolized by bacteria into organic acids, usuallyknown to promote the development of caries. To get a first impression of theincidence of dental plaque and decay in a population of bats, 203 individuals of A.jamaicensis were caught and examined. Only one individual showed a cavitationon one of its molars. Plaque staining with dye revealed that only about one thirdof the bats had plaque on their teeth surface. It was mostly concentrated ontheir lower premolars. To identify the members of the oral microbial community,swab samples from the bats’ mouth were taken and analysed by performingdenaturing gradient gel electrophoresis with amplified fragments of bacterialand archaeal 16S rDNA as well as by sequencing of 16S rDNA fragments. Wefound 28 different bacterial strains by sequencing 200 bp fragments of thebacterial 16S rDNA. Most of them belonged to the genera Streptococcus (28.6 %)and Pseudomonas (14.3 %). Strains probably associated with dental caries wereless frequent. We also found members of methanogenic archaea of the generaMethanoculleus and Methanosarcina in the oral cavity of A. jamaicensis. Thistype of archaea has been known so far only from the oral cavity of humans. Tounderstand more about appearance of dental decay and to establish new modelsystems of caries development, it is necessary to continue the field work in orderto use the knowledge gained out of the tropics for the human well-being.Wednesday WEDNESDAY 16:00 | FOYER | FoyergtöSociety for Tropical Ecology | Gesellschaft für Tropenökologie e.V. Status and future of tropical biodiversity | Frankfurt, 21 - 24 February 2011gtö