Document: JOH-3-64-26

The change in forested wetland canopy coverage after forty years of desiccation compared to seven years of rehydration.

VOLIN, J.C.* ¹, D.OWEN ¹, W.A.DUNSON ² and D.F.AUSTIN ¹

Florida Atlantic University, Davie, FL 33314, U.S.A. ¹
Pennsylvania State University, University Park, PA, U.S.A. ²

Abstract:
The Big Cypress Seminole Indian Reservation in southern Florida is located at a critical junction between the sawgrass Everglades basin to the southeast and the Big Cypress Greater Everglades Basin to the southwest. The geographic juxtaposition of protected lands around the Reservation, and the position of the Reservation on a tripartite, natural boundary of water basins, geological formations, and vegetation types, have led to it to be considered "critical" to Everglades restoration by both state and federal agencies. Therefore, together with the Army Corps of Engineers, the Tribe has agreed on a $49 million Water Conservation Plan (WCP). A component of the WCP will be to rewater natural areas on and connected to the Reservation. As a preliminary investigation of the effects of rewatering desiccated forested wetlands, we created a base layer of current land cover for a 80 Ha diked area that has been rewatered for the past seven years and for outside reference sites that have been continually desiccated since the 1950's. This base layer was generated from 1998 false-color infrared aerial photography. 1988 true color and 1953 black and white aerial photographs were georeferenced by image-to-image rectification and used to generate historical land cover maps. Overlay analysis of land cover maps was then used to assess changes in vegetation which may have occurred as a consequence of rewatering and desiccation, respectively. Preliminary results show that dessication leads to a significant encroachement of cypress (Taxodium distichum) trees into areas with historical hydroperiods of long inundation and deep depths and this encroachment is not reversed by subsequent rewatering. However, some native species not obligate to wetlands, such as laurel oak (Quercus laurifolia), have reduced coverage coincident with re-establishment of the historical hydrology. In contrast, contrary to preliminary predictions, canopy coverage of non-indigenous invasive species has not declined with increased water depth and time of inundation. Such comparisons of composition and structure of different community types at different time intervals before and after rewatering is important for evaluating the basin-wide performance of the restoration effort.

Keywords: Everglades Restoration

This abstract is being presented at: 10:30 AM in session:
RESTORATION ECOLOGY AND INVASIONS