| Abstract Detail
Tropical Biology Henderson, David [1], Tello, Sebastian J [2], Myers, Jonathan [3], Cayola, Leslie [4], Fuentes, Sigfredo [4], Loza, M Isabel [2]. Differences in local neighborhood biotic interactions show patterns of directional taxonomic structure but no pattern of functional trait arrangement. This study utilizes taxonomic and functional data to investigate how community diversity structures local interactions and whether tropical tree neighborhoods are more stochastically or deterministically arranged. We sought to investigate the role that community diversity plays in determining the nature of the interactions among the species in that community. High diversity and rarity in communities reduces the chances for species to interact frequently with one another, resulting in diffuse interaction. If species experience highly variable biotic (i.e. competitive) environments across space and time, a lack of consistent selective pressures may lead to diffuse evolution, where species fail to evolve niche differences (i.e. no character displacement) and instead converge on similar, more general life history strategies adapted to the long-term average of the environments they encounter. We used taxonomic and functional data to compare patterns of arrangement of the neighboring species of a focal species at three different neighborhood radii (10, 15 and 20m) over an elevational biodiversity gradient in the Bolivian Andes (elevational range from 200 to over 6000 m). We compared these patterns to a randomized null model to uncover how close the neighborhoods within the different communities are to a stochastic arrangement or how far they deviate from the model towards a deterministic arrangement. We found a significant taxonomic pattern of more stochastic neighborhood arrangements in high diversity, low elevation communities as well as a significant pattern of more deterministic neighborhood arrangements in low diversity, high elevation communities (R2 = 0.647, p-value = 3.00E08; 15m radius). We did not find a significant functional pattern within community tree neighborhoods (R2 = -0.0017, p-value = .3380; 15m radius) with the exception of the height of neighboring trees (R2 = 0.0901, p-value = 0.0558; 15m radius). The significant taxonomic pattern along with the lack of a significant functional pattern may indicate functional redundancy which suggests greater community resilience or that functional trait patterns are driven more by abiotic factors than by character displacement from the immediate biotic neighborhood. The deviation from the null model of neighboring trees in high diversity communities may indicate that large trees tend to be more abundant in the moist lowlands or that the layers of the canopy in the lowlands are of a more uniform height. This study highlights that while communities vary taxonomically in how deterministically or stochastically arranged they are, the functional traits that define the life history strategies of the species do not show a directional pattern of arrangement across the gradient. This information is valuable in determining conservation goals and predicting how communities may respond to an unpredictable future.
1 - Biology, 1 Booking Drive, St. Louis, MO, 63130, United States
2 - Missouri Botanical Garden
3 - Department Of Biology And Tyson Research Center, Campus Box 1137, One Brookings Drive, St. Louis, 63130, United States
4 - Herbario Nacional de Bolivia
Keywords:
Biotic interaction
ecological gradient
functional traits
madidi
community assembly.
Presentation Type: Oral Paper
Number:
Abstract ID:762
Candidate for Awards:None Canceled |
