Terrestrial Habitats. The main causes of impairment in the terrestrial habitats were loss of habitat area, fragmentation, altered hydrology, logging, the invasion of non-indigenous plant species, contaminants, and sedimentation of upland bogs, fens, marshes, and swamps. Logging has impaired the mesic and swamp forests. Removal of the largest (dominant) trees returns the forest to a lower successional state, decreases biodiversity of the entire system, removes food and nest/den sites, and opens up the canopy. Some of the losses of large trees with nesting cavities have been mitigated through nest box programs for such species as flying squirrels, wood ducks, bluebirds, and prothonotary warblers. More sunlight can enter the forest, which increases the temperature of the leaf litter and dries the forest floor reducing the amount of wet habitat needed by the associated invertebrate fauna and amphibians. Non-indigenous plants have invaded and often form monocultures through the forest. They include garlic mustard, Japanese knotweed, dame’s rocket, buckthorn and, in moister areas, Phragmites, purple loosestrife and xxxx-xxxxxx grass. The impairments they cause are: insufficient area to support wildlife populations; loss of plant biodiversity in the habitat; loss of habitat complexity; and decreases in nutritional food sources for wildlife.
Terrestrial Habitats. In the terrestrial communities, the invasion of exotic plants and harvesting of mast-bearing trees has altered the base of the food webs. Exotic plants, such as garlic mustard, Japanese knotweed, dame’s rocket, buckthorn and, in moister areas, Phragmites, purple loosestrife and xxxx-xxxxxx grass, often form monocultures thereby reducing the variety of foods and are often less nutritious than the native plants. Direct human disturbance has also reached the point of impairing wildlife populations thereby affecting community and food web functions. Through recreational use of habitats, people and their pets have negatively impacted these sentinel groups/species: diving ducks, the common tern, piping plover, and other shorebirds, bald eagles, black terns, snapping turtles and eastern spiny softshell turtle. In some instances, animals are scared from roosting or feeding areas, which incurs an energetic cost. In other instances, the reproduction of the organism is affected, which incurs a population cost. Human disturbance was noted as a factor affecting wildlife in a number of different habitat types: open water, islands, beaches, bluff, interdunal wetlands, mesic prairie, mesic forests and swamp forests. Only in submerged and floating macrophyte beds, beaches, and sand dunes was human recreational activity impairing the habitat, per se.