Abstract booklet - gtö – Society for Tropical Ecology

216 SCIENTIFIC POSTER SESSION | FOYERSCIENTIFIC POSTER SESSION | FOYER217Topic: Tropical island biodiversity: magnitude, function and conservationCOMPARATIVE ECOPHYSIOLOGY OF CARIBBEAN AND MAINLANDNEOTROPICAL TREESAdam R. Martin 1 , Sean C. Thomas 1 , Saara J. DeWalt 2 , Kalan L. Ickes 2 , ElvisR. Stedman 3Topic: Ecological networks and ecosystem functioningWEDNESDAY | FOYER1University of Toronto, Toronto, CA, adam.martin@utoronto.ca, 2 ClemsonUniversity, Department of Biological Sciences, Clemson, SC, US, 3 DominicaNaturalists Association, Laudat, DMIn tropical rainforests, interspecific variation in leaf- and wood functional traitsrepresents the spectrum of tree life-history strategies, from shade-intolerant“pioneers” to shade tolerant late successional species. Several studies haveinvoked functional trait variation across light gradients to explain tree species coexistence.While it remains untested, it may be expected that biogeographicaldifferences in disturbance regimes may drive community-level trait distributions.For instance, in Caribbean rainforests where large-scale disturbances with multidecadalreturn intervals (i.e. hurricanes) drive forest dynamics, one may expect treefloras to primarily express “pioneer” leaf and wood traits. However, in comparingleaf and wood functional traits across two forest types (hurricane disturbedforests in Dominica, versus seasonally dry Panamanian rainforests), we foundno evidence for disturbance-mediated shifts in traits. Common Dominican andPanamanian species exhibited similar ranges and distributions of photosyntheticcapacity (Amax), leaf nitrogen (N), leaf mass per area (LMA), and wood density(Dt). However, an interesting pattern unique to Dominican species was theecophysiological traits of 2 near-endemic dominant species, Amanoa caribaea(Euphorbiaceae) and Tapura latifolia (Dichapetalaceae). Both species haverestricted ranges from St. Lucia to Guadaloupe. When compared to 13 additionalcommon Dominican species, A. caribaea and T. latifolia consistently showed traitswhich bracketed the “shade tolerant” end of trait axes. For example, Amax valuesfor A. caribaea and T. latifolia were 3.15 and 3.09 μmol m-2 s-1, respectively, andonly one species (Licania ternatensis (Chrysobalanaceae), considered a “regionalendemic”) showed lower Amax. Similarly, A. caribaea and T. latifolia exhibited 2of the 3 lowest values for foliar N, and 2 of the 3 highest values for LMA and Dt.Overall, our results suggest severe disturbance regimes may not give rise tocommunity-specific functional trait distributions. However, our results regardingthe ecophysiology of dominant near-endemic tree species in Dominicanrainforests may provide some insight as to processes structuring Caribbeanrainforests. Specifically, our results suggest that tree species resistant or resilientto hurricane damage, and not fast-growing pioneers thriving in disturbed areas,may evolve locally and dominate hurricane-disturbed rainforest canopies.CALCIUM CYCLING IN THE SOIL-FIG-BAT COMPARTMENT OF ANEOTROPICAL RAIN FOREST ON SPATIALLY HETEROGENEOUSSUBSTRATE IN PANAMATobias Messmer 1 , Larissa Albrecht 2 , Elisabeth K.V. Kalko 2 , Elisabeth K.V.Kalko 3 , Wolfgang Wilcke 11Institute of Geography, Bern, CH, tobias.messmer@giub.unibe.ch, 2 Universityof Ulm, Institute of Experimental Ecology, Ulm, Germany, 3 Smithsonian TropicalResearch Institute, Balboa, PanamaCalcium concentrations in tropical soils are highly variable and commonly low.However, some plants, like Ficus insipida, show high Ca concentrations in theirfruit and leaf tissues. Frugivores like the bat Artibeus jamaicensis rely probablyentirely on fruits to meet their increased Ca demand during reproduction. Casupplies in soils of the Barro Colorado Island vary much depending on thegeological unit from which the soils developed. As Ca concentrations in figfruits and leaves are consistently high and vary much less than in soils thissuggests that figs use other Ca sources than soil. To investigate the fate andbehaviour of Ca, we instrumented three fig trees on each of the four geologicunits differing in Ca concentrations with stemflow and throughfall collectorsand litterfall traps. We determined (i) Ca supply in soils, fruits and leaves of thefigs, (ii) Ca fluxes with litterfall, throughfall and stemflow, (iii) the importanceof A. jamaicensis to the Ca cycle through pellets and faeces, (iv) the effectsof F. insipida on Ca concentrations in soil, and (v) the sources of Ca and thefractionation of Ca isotopes along the soil-plant-bat path.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