Seasonal Variation in Vegetation Classification on Perdido Key, a Barrier Island off the Coast of the Florida Panhandle

Abstract

The vegetation of 224 5 m x 2 m permanent plots located along 13 cross-island transects on the eastern end of Perdido Key, Florida, was classified using Two- Way Indicator Species Analysis. Seasonal variation in the vegetation classification was assessed using data collected in Autumn 1989, and Spring, Summer and Autumn 1990. Seven general vegetation types were recognized through the four seasons of data collection, with the greatest variation occurring within and between plots in the 'dune' vegetation type. In contrast, plots within the wooded dune and marsh vegetation types were the most stable between seasons. Four subtypes of the dune vegetation type were identified: established, disturbed, developing, and low dunes. However, consistent assignment of permanent plots to these subtypes was low and varied between seasons. Overall, the two Autumn classifications were more similar to each other than were either the Spring or Summer classifications to each other or to the Autumn classification. The problems in the development of a consistent classification of barrier island vegetation that can incorporate seasonal variations are discussed in the light of the conservation and management of coastal vegetation.