Natural Communities
South Florida Water Management District
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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.
In the early 1970s, 54 artificial islands were constructed for deer. Many of these are now covered with invasive vegetation.
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.
