Abstract booklet - gtö – Society for Tropical Ecology

168 PARALLEL SESSION HALL H IV THURSDAY LINK FOR SURVIVALPARALLE SESSION THURSDAY H III: LINK FOR SURVIVAL169HABITAT THRESHOLD EFFECTS ON GENETIC DIVERSITY ANDDIFFERENTIATION: EMPIRICAL EVIDENCE FROM A SPECIALISTSPECIES IN THREE ATLANTIC FOREST LANDSCAPESNiko Balkenhol 1 , Renata Pardini 2 , Cintia Cornelius 2 , Fabiano Fernandes 1 ,Simone Sommer 11IZW Berlin, Berlin, DE, balkenhol@izw-berlin.de, 2 Departmento de Zoologia,Instituto de Biociencias, Universidade de Sao Paulo, Sao Paulo, BrazilTHURSDAY 17:15 Hall H IVSimulation studies and literature reviews suggest the existence of afragmentation threshold, around 10-30% of remaining habitat, below whichbiodiversity loss is accelerated. Habitat thresholds could also affect differentcomponents of genetic variation, namely the amount of genetic variation(i.e., genetic diversity) and the distribution of genetic variation (i.e., geneticdifferentiation). Here, we provide the first test of habitat threshold effects ongenetic variation. Specifically, we used 12 microsatellite markers to analyze 529samples of Marmosops incanus, a small marsupial that is restricted to areas ofnative forest at both local and range-wide scales. Samples were gathered fromthree 10,000-ha landscapes differing only in the proportion of remaining forest(30, 50, and >80%). Using landscape- and patch-level analyses, we used thisdata set to address two interrelated questions: (1) Do genetic diversity, geneticdifferentiation and effective (i.e., genetic) immigration differ among landscapeswith varying proportion of forest cover? (2) Does the importance of local patchcharacteristics in determining genetic diversity, differentiation and effectiveimmigration vary among these landscapes? Congruent with our expectations,genetic diversity was significantly lower in the most deforested landscape (30%forest cover) compared to the two most forested landscapes. In contrast, geneticdifferentiation and effective migration did not differ between the 30% and 50%forest cover landscapes, while being significantly higher in the most forestedlandscape (> 80% forest cover). Finally, local patch characteristics explainedgenetic variation only in the most deforested landscape. Our study providesstrong support for the existence of habitat threshold effects on genetic variation.Results demonstrate that different components of genetic variation respondto habitat loss at varying rates, and that local patch characteristics becomeincreasingly important at higher levels of habitat loss. Furthermore, our studyillustrates the utility of genetic estimates of migration rates to evaluate habitatloss effects on effective dispersal. These findings have important consequencesfor understanding landscape- and patch-level effects on genetic variation, andfor conserving the most basic level of biodiversity in natural and human-alteredtropical landscapes.THURSDAY 17:15 Hall H IVgtöSociety for Tropical Ecology | Gesellschaft für Tropenökologie e.V. Status and future of tropical biodiversity | Frankfurt, 21 - 24 February 2011gtö