ILLUSTRATED FLORA OF EAST TEXAS - Brit - Botanical Research ...

182 INTRODUCTION/PRESETTLEMENT AND EARLY SETTLEMENT CONDITIONS OF BIG THICKET
FIG. 100/THREE-TOED BOX TURTLE (TERRAPENE CAROLINA TRIUNGUIS), A REPTILE OF THE BIG THICKET WITH A LIFESPAN OF MORE THAN 100 YEARS
(PHOTO BY GMD).
(Fig. 100). Individuals of this species can live for more than 100 years, and if conditions
remain constant, may spend their entire life in an area hardly larger than a football field
(Behler & King 1979). Their diet consists of such foods as slugs, earthworms, wild strawberries,
and mushrooms—including some poisonous to humans. This has resulted in human
fatalities as a result of eating “toxic” turtles (Behler & King 1979). Unfortunately, since they
are slow to reach sexual maturity (five to seven years), and because of habitat alteration (e.g.,
clearcutting, urbanization, etc.) and premature death due to other human activities (e.g.,
being crushed on highways), populations are declining in some areas. One reptile of particular
conservation interest is the Louisiana pine snake (Pituophis ruthveni), one of the rarest vertebrates
in the U.S. and a candidate for federal endangered species listing. This species was historically
known from longleaf pine-dominated habitats in Texas and Louisiana, but it is currently
known from only five total areas, two of which are in the Longleaf Ridge Conservation Area
on the northern boundary of the Big Thicket (Halstead 2002). In addition to habitat destruction,
alteration of the fire regime is thought to be a primary cause of Louisiana pine snake decline.
This is because the main prey of the species is the pocket gopher, which is dependent on the
abundant herbaceous vegetation present in a frequently burned longleaf upland (Rudolph &
Burgdorf 1997; Halstead 2002).
A stunning variety of other organisms, including fungi and insects, is also found in the
Big Thicket (e.g., Abbott et al. 1997). Perhaps one of the most surprising insects is the
Texas leaf-cutting ant (Atta texana) (Fig. 95), a fungus-farming, ground-dwelling species
which would be much more expected in the tropics. In fact, leaf-cutting ants range from
Argentina to Texas, with the Texas species being the northernmost (Kulhavy et al. 2004).
Leaf-cutting ants, which are important ecologically in soil-improvement, cut small pieces
out of leaves, carry them into their underground nests (to 8 m deep, with hundreds of
chambers), chew and infect the pieces with a fungus, and later harvest and eat the fungal
tissue (Kulhavy et al. 2004).