McMillan, Brett A. , Day, Frank P. .
It’s in the water: environmental and edaphic factors influencing plant assemblage composition on the ‘Pimple Dunes’ of Virginia’s barrier islands.
‘Pimples’ are small, rounded dunes that form parallel to the main dune ridges on the barrier islands off the Eastern Shore of Virginia. There are distinct plant assemblage habitat zones found on pimples, although most of them are 10 – 20 m in diameter. We sought to relate environmental factors to plant assemblage structure on the pimples because their unique morphology allows them to be used as naturally occurring mesocosms that replicate ecotones on barrier islands. At the onset, it seemed very likely that freshwater availability was the main determinant of differences between assemblages—not a surprising hypothesis for a barrier island. To determine what else was influential besides water, we examined several other environmental and edaphic factors for connections with dune plant diversity patterns, which we recorded through annual field vegetation surveys. Multivariate analyses revealed distinct assemblage types that segregated themselves by habitat type: marsh, shrub thicket and dry summit. Freshwater availability was not the only important factor in delineating differences in species distribution among these habitats. Mineral nutrients, such as boron, were also important in explaining variation among species. Our findings suggest that interactions between water and other factors (e.g., the accumulation of some nutrients in the marsh after they are leached from the dune summits), not simply water availability alone, determine patterns of species cover on pimple dunes.
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Virginia Coast Reserve Website
Brett McMillan's Website
1 - McDaniel College, Biology, 2 College Hill, Westminster, MD, 21157, USA
2 - Old Dominion University, Biological Sciences, Norfolk, Virginia, 23529, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Wasatch B/Cliff Lodge - Level C
Date: Monday, July 27th, 2009
Time: 3:45 PM