In geologic terms, the Everglades is young, only
having formed within the last 5000 years. Rich black soil began
forming and accumulating wherever sawgrass became the dominant
vegetation. The black color is from charcoal from frequent
lightning-caused fires. Sawgrass marsh is by far the most prevalent
natural community on Holey Land.
Few natural tree islands remain in the area.
In the early 1970s, 54 artificial islands were constructed to
improve deer habitat.
Drainage, drought, and decreased hydroperiod
(amount of time water covers the land) have caused loss of organic
soils in the Holey Land WMA as well as in other parts of the
Everglades. Under natural wet conditions, the bacteria living in
the remains of the plant cannot get enough oxygen to completely
decompose the plant material, and organic soil accumulates. When
the water is removed, so is the barrier between oxygen in the air
and bacteria in the soil. As a result, the bacteria now become
extremely active and in essence consume the soil. In The
Everglades: An Environmental History, David McCally reports
that at one site in the Everglades, 6.8 feet of soil was lost
between 1912 and 1950. Dry organic soils, which burn easily and
rapidly, are further lost through fire.
Portions of Holey Land have experienced an
explosion of cattail growth since water levels were restored in
1991. Cattails often replace sawgrass in areas where water is high
in nutrients. Agricultural runoff is generally the source of
increased nutrients in the Everglades. The extent of willow shrub
has been reduced as a result of higher water levels.
Water Management District
The Commission conducts annual surveys to determine the extent
of cattail in the area and works with state and federal agencies to
improve the quantity and quality of water deliveries. Cattail
coverage has decreased over the past decade due to better
management of water levels. Although a native species,
cattails choke out open-water habitat vital to alligators, wading
birds, and waterfowl.
Prescribed burning and treatment of exotic
vegetation are also important management strategies used to improve
wildlife habitat in Holey Land WMA.