Abstract Detail


Henderson, David [1], Sedio, Brian [2], Tello, Sebastian J [3], Cayola, Leslie [4], Fuentes, Alfredo F. [4], Alvestegui , Belén  [5], Muchhala , Nathan  [5], Myers, Jonathan [6].

Testing the Role that Biotic Interactions Play in Shaping Elevational-Diversity Gradients: An Ecological Metabolomics Approach.

Foundational hypotheses in ecology and evolution posit that stronger and more specialized biotic interactions contribute to higher species diversity at lower elevations and latitudes. Plant-chemical defenses mediate biotic interactions between plants and their natural enemies and provide a highly dimensional trait space in which chemically-mediated niches may facilitate plant species coexistence. However, the role of chemically-mediated niches in shaping plant communities remains largely untested across large-scale ecological gradients. To test this hypothesis, we used ecological metabolomics to quantify the chemical similarity of leaf secondary metabolites of 906 tree species in 16 tropical communities along an elevational gradient in the Madidi National Park, Bolivia. We predicted that chemical similarity among co-occurring tree species would be lower in communities with higher species richness and warmer, wetter, and less-seasonal climates.   Our results support the hypothesis that chemically-mediated niches shape diversity gradients. Across the 16 forest plots, median pairwise chemical similarity among tree species decreased with species richness (P = 0.03 R2 = 0.33). Median chemical similarity also varied systematically with climate, with lower chemical similarity in communities with higher mean annual temperature, annual precipitation, and temperature annual range (P = 0.02; R2 = 0.32). Our results suggest that natural enemies impose a stronger biotic selective pressure on plant chemical defenses in more-diverse communities and more-productive climates. In turn, spatially-variable biotic pressure from natural enemies may be an important process shaping elevational-diversity gradients. Our study also illustrates the promise of ecological metabolomics in the study of biogeography, community ecology, and complex species interactions.

1 - Biology, 1 Booking Drive, St. Louis, MO, 63130, United States
2 - University of Texas at Austin, Department of Integrative Biology, Austin, TX
3 - Missouri Botanical Garden, Center for Conservation and Sustainable Development, St. Louis, MO, USA
4 - Herbario Nacional de Bolivia, Bolivia
5 - University of Missouri St. Louis, Department of Biology, St. Louis, MO, USA
6 - Washington University in St. Louis, Department of Biology, St. Louis, MO, USA

plant ecology
Tropical biodiversity
Community composition
ecological gradient
chemical defense.

Presentation Type: Oral Paper
Number: EC11004
Abstract ID:768
Candidate for Awards:Ecological Section Best Graduate Student Paper

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