ABSTRACT
Observations of significant reductions in submerged aquatic vegetation (SAV) populations have been reported worldwide, attributed especially to increased light attenuation (Dennison et al. 1993). Decline of SAV has been pronounced in coastal waters and estuaries of the Gulf of Mexico (Duke and Kruczynski 1992). In some locations the declines are 20% of historical levels (e.g., Tampa Bay, Florida, Lewis et al. 1985), whereas other areas have losses accruing to 40-50% of historical
distribution and abundance. These submerged vascular plant communities are recognized as one of the most important ecological communities in shallow coastal waters (Zieman and Zieman 1989). Coastal populations of SAV exhibit high primary production, often exceeding highly manipulated tropical croplands (Zieman and Wetzel 1980). Furthermore, SAV habitats support numerous important ecological functions for a variety of aquatic organisms, including invertebrate, fish, turtle, bird, and mammal species (McRoy and Helfferich 1980). In addition to contributions to maintenance of food webs, SAV functions in nutrient cycling, stabilizing fine sediments and mitigating shoreline erosion dynamics (Phillips and McRoy 1980; Korschen and Green 1988). Therefore, related to the importance in these diverse ecological functions, SAV beds have become widely recognized as sentinels of the ecological status for estuarine ecosystems (Thayer et al. 1975; Livingston 1984; Doust et al. 1994; Neckles 1994). It is important to environmental and living resource managers to minimize SAV losses, as previously reported in nearby Escambia Bay (Olinger 1976), and foster re-establishment of SAV communities. Thus natural resource agencies have increased their interest in protection, restoration, and creation of wetlands in general with seagrass and estuarine SAV habitats, and communities are receiving increased attention (Morris and Tomasko 1993).
