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Pawpaw
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Scrub Pawpaws (Asimina obovata) are on the left side
of the trail. Like many scrub species, this pawpaw differs from its
woodland relatives by having thick leathery leaves with a heavy water
conserving wax layer. The cream-colored flowers appear in the spring,
have a fruity odor, and are pollinated by scarab beetles. The seeds are
dispersed by fruit-eating mammals.
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South Florida Slash Pine
Pinus elliottii
Slash Pine
art by M Deyrup
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click to enlarge
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Slash Pines have long needles and thicker terminal
twigs. The bark is thick and provides protection from rapidly burning
ground fires. The South Florida Slash Pine is very similar in appearance
and ecology to Longleaf Pine (P. palustris). Like Longleaf Pine, it forms
open stands over a low ground cover of palmettos, grasses, and herbs.
South Florida Slash Pine is well adapted to fire. Young plants have a
"grass stage" when there is little top growth but extensive
root system development. After several years, the plants suddenly grow
rapidly into the canopy. This growth pattern minimizes the length of
time in which the growing point and foliage of the tree are highly
vulnerable to ground fires. Populations of Slash Pines off the Ridge in
central and northern Florida do not have this growth pattern. Slash
pines may live up to 200 years. The oldest Slash Pine at the Station is
170 years old (aged by taking a sample of the core of the tree through
the use of a boring tool called a core borer). Myrtle Oaks are also
abundant in this area. Individuals can be seen on either side of the
Marker.
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In recent years, fire ecology
has become a major area
of research at the Archbold Biological Station. This patch of 5.8 acres
of scrubby flatwoods was burned on 29 October 1990. Although some of the
pines have died, most of the other plants have resprouted or seeded in.
Central Florida is the lightning capital of the U.S. due to Florida's
summer weather patterns. Thunderstorms occur throughout the year but
especially during May - September. Lightning fires start when a bolt of
lightning strikes outside the area of rainfall, or ignites fuel that
smolders until the rain ends and the leaf litter dries. Before the
pioneers came to Florida, scrub vegetation burned freely and regularly.
We now know that scrub becomes over-grown and loses its diversity if not
burned every 20-40 years or so. Many of the endemic organisms of scrub
cannot live in unburned areas.
click to enlarge
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Fire has always been a part of most Florida habitats.
Frequent lightning strikes, combined with a pronounced dry season, have
always caused many wildfires. Plants and animals of scrub, flatwoods
and other habitats have evolved adaptations to fire. The oaks, palmettos,
grasses, and many other plants sprout rapidly from growing points
protected in the sand. Other species, such as Florida Rosemary
(Ceratiola ericoides), are killed by fire but recover from seeds that
germinate following fire. Sand Pine seeds are stored in cones on the
tree for decades, and are released when heat from fire melts a wax
coating and allows the pine cones to open. Many organisms depend on
the open, post-fire conditions to survive, including the Florida Scrub
Jay, which begins to disappear once scrub stands grow head-high and
sandy areas become shaded. At Archbold, this happens about 20 years or
so after fire. In the Twentieth Century, fire suppression and man-made
fire barriers between natural habitats (such as roads, housing
developments, citrus groves, etc.)
Aphelocoma coerulescens
Florida Scrub-Jay
art © Turid Forsyth |
have decreased the extent of fires.
click to enlarge
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This has allowed many areas to develop dense thickets of tall shrubs
and trees. At Archbold and on many public lands, prescribed fires
restore and manage natural ecosystems and provide habitat for endangered
and threatened species.
To your left, as you walk the Nature Trail, is an
area that was burned in December 1992, after over 60 years without fire.
You will see areas that have not burned, have lightly burned, or have
burned with high intensity. This variation is typical of fires in
Florida Scrub. You will also observe the recovery of the vegetation and
perhaps flowering displays stimulated by burning. For contrast, on your
right you will first pass a strip of vegetation long-unburned, and later,
from Markers #10 to #20, an area burned in the fall of 1990.
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Gopher Apple
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Gopher Apple (Lycania michauxii) is the low plant
with shiny yellow-green leaves forming an extensive mat to the right of
the Marker. The individual shoots are connected by underground woody
stems. A spring bloomer, its flowers are highly attractive to bees and
wasps. The fruits are eaten by wild mammals and Gopher Tortoises, and
are edible for humans.
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Bridge and Ditch
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The bridge and rock-lined drainage ditch were built
by John Roebling in the early 1930s, in preparation for developing the
area as his estate. Mindful of the frequent natural disasters in the
area, and unaware of the adaptations of native organisms to deal with
these disturbances, he protected his land from both flood and fire. This
area is now much drier than it used to be. Both John and Margaret
Roebling had a great interest in native plants and animals. Highlands
Hammock State Park, just west of Sebring, was another Roebling project.
click to enlarge
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After crossing the bridge, you will walk along an
area of thick palmettos on your right-hand side. Palmettos such as these
often serve as daytime refuge areas for Opossums (Dideiphis marsupiahs),
Raccoons (Procyon lotor), and other nocturnal animals. Keep a lookout
for other clues to the presence of mammals such as holes dug for food,
runways in the sand or leaf litter, scats, and of course, animal tracks.
You may wonder if you will see a snake. If you are
very lucky you might get a glimpse of one of the more common snakes that
live in this area, the Indigo (Drymarchon corais couperi), Black Racer
(Coluber constrictor priapus) or Coachwhip (Masticophis f. flagellum), but
it is far more likely that you will not see one along this trail.
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Nest Box
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The nest box on this pine is one of many used in
long-term monitoring of populations of cavity-nesting vertebrates.
Residents of these boxes are captured, counted, measured, weighted,
marked, and released. Nest boxes are used by Eastern Gray Squirrels
(Sciurus carolinensis), Southern Flying Squirrels (Glaucomys volans),
Eastern Screech-owls (Otus asio), Great Crested Flycatchers (Myiarchus
crinitus), American Kestrels (Falco sparverius), and occasionally other
birds, bees, and various other invertebrates. These boxes form important
nest sites in areas where natural cavities are scarce.
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Lichens and Contrasting Pines
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