The Tampa Bay Estuary is a diverse ecosystem
Tampa Bay boasts a diverse palette of habitats, from open-water rubble and reef communities to lush seagrass meadows and coastal hardwood hammocks.
Estimated losses of nearly half the bay's wetland habitats since the 1950s led to development of TBEP's "restoring the balance" strategy to guide restoration efforts. This approach recognizes that losses of some habitat types, such as low-salinity tidal marshes (-38%), have been disproportionately greater than for others, such as mangrove forests (-13%). While seeking to maximize recovery of those habitats hardest hit by development activities, "restoring the balance" also calls for preserving and enhancing existing mangrove and marsh communities through land acquisition, invasive species eradication and regulatory protections.
Specific goals for emergent habitat restoration and protection, as incorporated in the Habitat Restoration Master Plan, are:
Mangroves line the shore of the estuary, providing shelter for young marine life
From 1995- 2001, more than 378 acres of low-salinity, or oligohaline, habitats were restored, far exceeding the original goal of 100 acres every five years. These critically important areas are vital to the survival of juvenile snook and mullet as well as numerous wading birds. A new research initiative, begun in 2005, will quantify specific water and sediment quality requirements for oligohaline tributaries of the bay, particularly small streams and creeks about which little is presently known.
Overall, about 2,350 total acres of marshes, mangroves and other benchmark habitats were restored in the Tampa Bay ecosystem from 1996-2003, primarily through projects coordinated by the Southwest Florida Water Management District's Surface Water Improvement and Management (SWIM) program. More than 60 percent of the total restored acres were marshes or mangroves, while 27 percent were coastal uplands. Pending projects will triple the amount of habitat restored in the next decade, as larger efforts that provide significant wildlife corridors and emphasize creation of a "mosaic" of diverse habitat types take shape.
The Habitat Restoration Master Plan also emphasizes the restoration or protection of small freshwater ponds in the vicinity of white ibis and other wading bird rookeries, as the crayfish and frogs found in these ponds are a critical food source for ibis chicks. Some progress has been made in preserving or restoring freshwater ponds, but the gains are not fully documented at present.
The Master Plan also identified 28 priority sites for protection to be managed or restored as necessary, either direct purchase or other means such as conservation easements on private property. These sites were earmarked "high priority" by the Southwest Florida Water Management District in the state's Save Our Rivers and Florida Forever land-buying programs. A total of 11,494 acres of estuarine habitat was preserved through acquisition of these top-priority sites by TBEP partners between 1996 and 2003.
Critical habitats not included in the 1995 Bay Habitat Master Plan are hard-bottom habitats, including submerged rock or rubble reefs as well as oyster bars. These important habitats will be included in an updated Master Plan now being developed. Projects already are underway to map the extent and location of historic oyster bars in the bay and compare those with existing aerial photographs, and to evaluate the effectiveness of various artificial reef designs currently utilized in the bay.
Improvements in water quality have fueled steady gains in seagrass recovery, averaging about 350 acres per year, over the past decade. Seagrasses are among the bay's most vital habitats, harboring an abundance of sea life. These flowering marine plants are generally found in waters 6 feet deep or less in Tampa Bay, where sunlight can penetrate the water column. Seagrass beds are important nursery and feeding grounds for several commercially and recreationally important species in Tampa Bay, including shrimp, spotted sea trout, red drum, and snook.
TBEP and its partners have established a seagrass recovery goal of approximately 12,000 acres, while preserving the bay's existing 26,000 acres, for a total of 38,000 acres baywide. By 1997, about 4,000 new acres of seagrass were documented. However, record-setting El Nino rains from 1997-1999 erased some of those gains, resulting in a loss of about 2,000 acres from nutrient-laden stormwater runoff that clouded the water. Seagrasses rebounded by about five percent to 26,078 acres in 2002.
The most recent aerial surveys conducted by the Southwest Florida Water Management District, assessing changes from 2002 to 2004, show a continued, albeit slower recovery of 946 acres baywide, or about 4 percent from 2002-2004. Gains were documented in every bay segment except Old Tampa Bay, where seagrasses declined by 636 acres, or 12 percent, during this two-year period. This segment has experienced a steady loss of seagrass since 1982.
It is important to note that the 2002-2004 surveys were completed prior to the record-setting 2004 hurricane season, and do not account for any impacts from associated wastewater and phosphogypsum stack spills.
The lagging recovery of seagrasses in Old Tampa Bay, and especially a 2,000-acre area in Feather Sound, remains a key focus of research sponsored by the Tampa Bay Estuary Program beginning in 2003. Among potential causes of the seagrass declines are poor water quality, reduced circulation and flushing, and increased epiphytic growth on grass blades (which can prevent sunlight from reaching the blades), but studies so far are inconclusive. Solving the puzzle of the seagrass die-backs in Old Tampa Bay is critical to achieving the baywide seagrass recovery goal set by TBEP.
Wave erosion from passing ships is also suspected as a culprit in seagrass losses in some parts of the bay. Historical photos indicate that the presence of natural longshore sandbars that once existed in many areas may have helped to buffer wave action, allowing seagrass to flourish in the shallow waters landward of the bars. A pilot project to test this theory was launched in 2005 to reconstruct an experimental longshore bar along the southeastern shoreline of the bay.