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Wetland Creatures
(adapted from Wetlands and Wildlife, Brooks et al. 1993)
Wetlands provide important and sometimes critical habitats for many plants and
animals. An estimated one-third or more of all endangered or threatened species
in the United States depend on wetlands for survival. Wetland ecosystems
provide important nesting, wintering, and feeding sites for many wildlife species.
In fact, wetland ecosystems are one of the most productive wildlife habitats in
Pennsylvania.
Most people associate species such as waterfowl, herons, beavers, muskrats
and river otters with wetlands. These species are termed obligate wetland
species because they depend on or are obligated to inhabit wetlands for survival.
Many other species of wildlife use wetlands. Some do so at length. Because,
these species are not as dependent on wetlands for their survival, we call this
group of animals facultative wetland species. Good examples of facultative
species include the black bear who use Pocono wetlands and ring-necked
pheasants who use wetlands as escape areas when available.
Reptiles and Amphibians
Virtually all amphibians require
access to water and wetlands during
their breeding cycle. Their delicate
jelly-like eggs must be kept moist
during development. In addition to
requiring water for breeding, many
species, particularly frogs, live in
water year round.
Salamanders are a particularly
diverse group in Pennsylvania and
other Appalachian states. Dozens of
species have evolved in the isolated
valleys of the geologically old Appalachian mountains.
Although reptiles evolved primarily on drier lands, some species have reverted
back to dependence on aquatic habitats. Species such as the painted turtle and
northern water snake live in water, but lay their eggs high and dry on land. Thus,
reptiles and amphibians differ in their use of wetlands. Both groups rely on
wetlands and other water bodies for survival. Even the smallest of temporary
ponds (sometimes called vernal ponds), that are dry for much of the year, are
critical habitat for these species.
Fish
About 30 species of fish are known to use freshwater wetlands in Pennsylvania
some time during their life cycle. Fish such as sunfish and catfish will nest in the
shallow open-water areas of wetlands, ponds and reservoirs. Other species such
as bass, pickerel and pike require vegetated habitats with dense stands of plants
on which to lay their eggs and raise their young.
Wetlands connected to other water bodies, such as streams, lakes and estuaries,
are more likely to contain a variety of fish species, particularly those that move to
and from deep waters and shallow waters for feeding and breeding.
Invertebrates
Invertebrates are the most abundant and varied of all wetland animals, at least
those that we can see without the aid of a microscope. Invertebrates inhabit both
aquatic and terrestrial environments. Invertebrates are associated with nearly all
other animals as food, predators, parasites
and/or competitors for available resources or
space.
Aquatic invertebrate play an important role in
decomposing dead plant and animal material in
wetlands. Crane fly larvae and earthworms are
two examples. Invertebrates are also important
pollinators of plants, such as wetland orchids.
Macroinvertebrates such as crayfish, mayflies,
dragonflies, damselflies, caddisflies and
stoneflies are major part of the diets of other
wetland animals such as fish, amphibians,
shorebirds, songbirds, waterfowl and insecteating mammals.
Wetland Plants
Many familiar plants grow in wetlands.
Blueberries and cranberries are examples of
wetland plants that we favor. Wetland plants are
able to take-up nutrients and toxins and transform them. The plants in a wetland
are the basis for all other life forms which exist there. They offer shelter and food
to insects, birds, mammals, fish, reptiles and amphibians. (Figure Source: N.
Obel).
Some wetland plants only occur in wet areas and others may occur in wet or dry
areas. Many wetland plants have special adaptations that allow them to live in
water. The roots of some wetland plants have evolved air spaces as a result of
low oxygen in the sediment. Some wetland plants produce seeds during the dry
season and others may produce seeds that can float to the banks to take root.