(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 insect-eating 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.