FYI,
Steve
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America's Vanishing Biodiversity
By Catherine Lazaroff
Environment News
WASHINGTON, DC, September 21, 1999 (ENS) - Biological diversity in the
United States is declining dramatically, a new U.S. Geological Survey
assessment shows. The agency�s report underscores the need for science
to be used in guiding decisions on resource management.
The two volume report, "Status and Trends of the Nation's Biological
Resources," compiles current scientific research within a historical
perspective to document how the nation's biological resources are
changing. The U.S. Geological Survey (USGS) says the report is the first
large scale assessment of the nation's natural resource heritage.
"This study is a CT scan of our nation, and like a doctor, it can give
us a diagnosis as to what we need to do to restore the health of our
living landscapes," said Interior Secretary Bruce Babbitt. "The rest is
up to us."
Almost 200 federal, academic, and non-governmental experts provided
baseline information to scientists, policy makers, resource managers and
the public. The 1,000 page scientifically peer reviewed report took four
years and $1 million to complete, and details both the issues affecting
biological resources and the status and trends of specific regions.
The report documents that land use changes including urbanization,
conversion of lands to agriculture, draining of wetlands and the
fragmentation of forests are the major factors leading to the loss of
biodiversity.
In the central U.S., the report finds that decades of fire suppression
and heavy grazing have led to the widespread disappearance of native
grasslands.
"For example, in seven states once covered with native grasslands, less
than 1 percent of the native tall grass prairie habitat remains," said
USGS director Dr. Charles "Chip" Groat. "Losses are due to agriculture,
grazing, urbanization and mineral extraction. The result is that native
grassland bird species have shown more consistent, widespread and
steeper declines than any other group of North American birds."
In the Pacific Northwest, old growth forest logging has led to alarming
declines in a number of birds and plants. At least 83 percent of the
region�s old growth Douglas fir forests have been destroyed, along with
75 percent of the coastal rain forests in Washington state. In
California, 85 percent of the state's old growth redwoods have been cut
down.
Not only high profile species like spotted owls are affected by the
forest losses. Officials in Washington can no longer locate leopard
frogs across much of their historic range, for example. In Oregon�s
Willamette Valley, sharp tailed and ring necked snakes, western
rattlesnakes and common king snakes have nearly disappeared. Birds like
the golden crowned kinglet, Wilson�s warbler and winter wren, all
inhabitants of old growth forests, are vanishing.
"Although we know a great deal about some biological resources - such as
birds, large mammals and some fish species - information is often
spotty, incomplete or nonexistent for most taxonomic groups," Groat
said. "We don't, for example, know the status and trends of many species
of amphibians and reptiles, of invertebrates, of a great number of
plants, of smaller mammals, and of the vast majority of ocean dwellers.
And yet, information presented in the report gives great cause for
concern about certain populations of these lesser studied species."
Fish and other aquatic organisms dominate the lists of species at risk.
The report blames hydroelectric and flood control dams, and the
diversion of water for agricultural use, for the fact that 19 percent of
freshwater fish and 73 percent of freshwater mussels in the Southeast
are endangered or threatened. In the Southwest, fully 48 percent of fish
species are at risk.
Almost 60 percent of California fish species have gone extinct or are
"on the road to extinction if present trends continue," the report
states. More than half of the state's frog species are endangered or
threatened.
Californians have also eliminated 91 percent of the state's wetlands and
99 percent of grasslands. One in five of the state�s 342 land bird
species are listed as endangered by the state or federal governments.
"As water supplies were acquired by large development interests with the
political and financial ability to move water to the semideserts of
southern California, the growth of cities and agriculture greatly
accelerated, resulting in the loss of the incredible richness of the
Central Valley," the report states.
Groat called invasions by non-native species one of the most important
issues in natural resource management and conservation biology today.
"Invasive species are especially troublesome because many of them have
become established in habitats that have no natural competitors or
predators, enabling the invaders to thrive to the extent where they
either out-compete native species, significantly alter habitat or both,"
he said.
Non-native species are particularly devastating on island communities.
In Hawaii, about 90 invasive plant species pose significant threats to
the state's ecosystems.
The report does include some good news as well. Species that adapt well
to human activities, including birds like the Stellar�s jay and common
yellowthroat and mammals like the coyote and red fox, are thriving. Bald
eagles and peregrine falcons have made dramatic recoveries since the
pesticide DDT was banned.
Efforts to clean up the Great Lakes have removed toxic chemicals and
excessive amounts of nutrients from the lakes, which, in turn, has
sparked the revival of burrowing mayfly populations in Lake Erie.
"The report documents the status and trends of individual species and
particular habitats, which, if lost, can threaten the ecosystem
functions on which humans depend," said Dr. Michael Mac, the USGS
project director for the report. "In the face of environmental change,
biodiversity may provide the stability that buffers ecosystems."
� Environment News Service (ENS) 1999.
