Dune plant species diversity and function in two barrier island biogeomorphic systems |
| |
Authors: | Anthony Stallins J |
| |
Institution: | (1) Department of Geography, Florida State University, Tallahassee, FL 32306, USA |
| |
Abstract: | Barrier island dune systems exhibit strong geographic contrasts in theinteraction between extrinsic disturbance from storm overwash and intrinsicbiogeomorphic recovery processes. To examine how these interactions shape duneplant species diversity, I sampled species cover and topography alongfrequentlystorm-overwashed (South Core Banks, North Carolina) and infrequently overwashed(Sapelo Island, Georgia) barrier islands. The observed compositional anddiversity patterns were in agreement with a complex systems model in whichextrinsic overwash exposure is either reinforced (South Core Banks) or dampened(Sapelo Island) by intrinsic biogeomorphic controls of topography. A largespatial-scale regularity in the distributional pattern of along-shore speciesdiversity was correlated to primary foredune height on South Core. On Sapelo, afine-spatial scale differentiation of species diversity patterns was lessstrongly correlated to topographic metrics. There were no significantdifferences between islands in along-shore alpha diversity (Shannon-Weinerindex). However, Sapelo was more diverse given its smaller area and finer-scalehabitat heterogeneity. I posit that the relevancy of the IntermediateDisturbance Hypothesis is weak when examining diversity patterns along a shoredisturbance gradient. Intrinsic biogeomorphic processes decouple the directcause-and-effect relationship between disturbance and diversity, a basicassumption of IDH. I posit that the Dynamic Equilibrium Model may be a moregenerally applicable conceptual framework. DEM incorporates the interaction ofintrinsic and extrinsic processes that shape habitat heterogeneity, aprerequisite for understanding how complex systems interactions shape diversitypatterns. |
| |
Keywords: | Dynamic equilibrium model Intermediate disturbance hypothesis Plant functional types Species diversity |
本文献已被 SpringerLink 等数据库收录! |
|