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Wetland: Simply put, wetlands
are areas where land and water blend in varying quantities,
and where the presence of this water at or near the soil surface
drives the natural systems-including the kind of soils that
form, the plants that grow, and the fish and/or wildlife communities
that use the habitat. Freshwater wetlands in the United States
have shrunk from more than 200 million acres in 1780 to less
than 100 million acres today, primarily because of conversion
to agriculture and other development. Among the continued
threats to wetland habitats are the draining and diversion
of water, loss of water quality, invasive plant species, and
urban encroachment.
Forest: Forested habitat features
trees that are at least 20 feet tall and provide an overhead
canopy cover of at least 50 percent. About a third of the
continental United States is covered by forested woodlands,
down 30 percent from pre-European settlement times; most losses
have been in the East. Healthy forested habitat is at risk
from unsustainable logging, plantation forestry, overgrazing
by deer or livestock, new tree diseases, invasive species,
conversion to agriculture, too-frequent or too-scarce fire,
resource extraction, urbanization, and fragmentation by roads
and utility lines. next page >>