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Section 2 Existing Conditions/Affected Environment

EAA Storage Reservoirs Revised Draft PIR and EIS February 2006

2-15

Forested wetlands in the WCAs include both strands and hydric hammocks. A

strand is a broad, shallow channel with peat over a mineral substrate that is

seasonally inundated by flowing water. Fire is occasional or rare in this wetland

community and dominant vegetation is cypress and/or willow. The following

vegetation species are associated with this community: pond cypress, bald

cypress, willow, buttonbush, wax myrtle, sawgrass, and royal fern.

A subtropical hydric hammock is a wetland forest community occurring in the

WCAs in lowlands over sandy, clay organic soil, often over limestone. Its water

regime is mesic to hydric and fire is rare or not a major factor. The following

species are associated with this community: sweet bay, red bay, cocoplum,

strangler fig, wax myrtle, willow, elderberry, hackberry, cabbage palm, red

maple, false nettle, water oak, hornbeam, and needle palm.

Major plant communities in WCA-2A now consist of remnant drowned tree

islands, open water sloughs, large expanses of sawgrass, and sawgrass

intermixed with dense cattail stands. Remaining tree islands are found

primarily at higher ground level elevations, located in the northwest corner of

WCA-2A. Remnant (drowned) tree islands, dominated primarily by willow, are

found scattered throughout the central and southern sections of WCA-2A.

Cattail distribution in WCA-2 reflects 4,400 acres in which cattails represent

more than 50% of the vegetation coverage and 24,000 acres of mixed or scattered

cattail (<50% coverage) present in the northeast portion of WCA- 2A.

Several studies conducted within WCA-2A show that cattail out-compete

sawgrass in their ability to absorb nutrients. There is increased cattail

production during years of high nutrient inflows (Toth, 1988; Davis, 1991).

Cattail is considered a high nutrient status species that is opportunistic and

highly competitive, relative to sawgrass, in nutrient-enriched situations (Toth,

1988; Davis, 1991). Davis (1991) concluded that both sawgrass and cattail

increased annual production in response to elevated nutrient concentrations, but

that cattail differed in its ability to increase plant production during years of

high nutrient supply.

The community structure and species diversity of Everglades vegetation located

north of I-75 (WCA-3A North) is very different from the wetland plant

communities found south of I-75 (WCA- 3A South). Improvements made to the

Miami Canal and impoundment of WCA-3A by levees have over-drained the

north end of WCA-3A and shortened its natural hydroperiod. These hydrological

changes have increased the frequency of severe peat fires that have resulted in

loss of tree islands, aquatic slough, and wet prairie habitat that were once

characteristic of the area. Today, northern WCA-3A is largely dominated by

sawgrass and lacks the natural structural diversity of plant communities seen in

southern WCA-3A.

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