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Amphibians in Washington among nation’s most threatened

Nature Conservancy study finds nearly one-third of state’s amphibian species at risk

SEATTLE, WA — April 22, 2002 — Washington's amphibians–from the Oregon spotted frog to the larch mountain salamander–are among the nation's most threatened, with 32 percent of the state's amphibian species imperiled, according to a new state-by-state analysis released today by The Nature Conservancy.

The study, States of the Union: Ranking America's Biodiversity, placed Washington fourth in the nation for the number of amphibian species considered rare or imperiled. Overall, the state supports 25 amphibian species, several of which are found only in Washington or the Pacific Northwest.

The report also found that Washington has one of the country's most diverse bird populations. The state is home to 372 different species, making it the sixth most diverse in the country. Of those bird species, three percent are at risk–the fifth highest in the state-by-state ranking.

Overall, the study shows that Washington, like other Western states, is both biologically rich and in grave danger of losing some of that immense natural heritage.

"This report holds both hope and peril," said David Weekes, director of the Conservancy's Washington chapter. "As a snapshot of the state's biological health, it suggests an extraordinary richness, particularly in bird and amphibian life. At the same time, the report shows that unless we significantly increase our conservation efforts, many of these animals are at risk of vanishing forever."

The Conservancy is working across the state to safeguard Washington's rich natural heritage, using a number of different strategies to put land and water into protection. Much of that work is protecting habitat that supports imperiled amphibians.

At Ellsworth Creek in the Willapa Hills, the Conservancy is working to protect some of the region's last remaining temperate coastal old-growth rainforest, especially diverse because of its mild climate, abundant rain and gentle topography. The old-growth forests within the creek's basin support a vast array of amphibian life, including 13 different salamander species, some of which are found only in the Willapa Hills and are considered at risk.

At the Black River in Thurston County, The Nature Conservancy is working closely with the U.S. Fish and Wildlife Service to fill in the boundaries of a newly created refuge there. The Conservancy advocated for the creation of the refuge–a unit of the Nisqually National Wildlife Refuge–and has purchased and transferred to the Service more than 400 acres. Scientists just recently found several egg masses there for the Oregon spotted frog, an animal that has been reduced to only a few populations in Washington state.

Amphibians–frogs, toads, salamanders and newts--are considered important indicators of ecological health, largely because of their enormous sensitivity to changes in the environment. Bill Leonard, an amphibian expert who works for the National Marine Fisheries Service and has conducted studies for The Nature Conservancy, said there are numerous theories about why amphibians are on the decline.

The leading cause, he said, is habitat destruction, particularly the draining of wetlands and the conversion of forestland. Several studies also suggest that pesticides and other human-introduced chemicals are profoundly affecting amphibians. The introduction of non-native predators, such as introduced fish in stocked lakes and rivers, is considered another leading cause.

"Whatever the reason," Leonard added, "it's imperative that we protect their habitat, especially those areas–like Ellsworth Creek–where they appear to be thriving."

The report, based on an analysis of more than 21,000 species, was conducted for The Nature Conservancy by NatureServe, a non-profit organization considered one of the world's most important sources of scientific information about rare and endangered species and threatened ecosystems. The New York Times has called NatureServe's databases on species and ecosystems "the country's leading source of biological information for conservation planners, government agencies and land managers."

The study's authors drew upon species inventories compiled by state natural heritage programs across the country. Using a rigorous methodology that explored the number and condition of species' populations, their trends, and their known threats, the authors were able to rank all 50 states and the District of Columbia on several key biological characteristics, including levels of rarity and risk.

The study follows on The Nature Conservancy's highly acclaimed book Precious Heritage: The Status of Biodiversity in the United States, a comprehensive assessment of the condition of the United States' biological richness. Precious Heritage, published in 2000, underscored the country's diversity; it found, for instance, that the United States is a global center of diversity for many groups of organisms, especially those that rely on aquatic systems such as salamanders, freshwater mussels and freshwater turtles.

The latest study builds on these findings, indicating those areas of the country where there is the greatest species diversity as well as the most serious risks. Areas with the greatest species diversity are found in the topographically and climatically diverse Southwest, with California (6,717 species) and Texas (6,273 species) leading the nation. This is due in part to the enormous size of these two states, their ecological complexity and their location.

Risk patterns among states–as reflected by the proportion of a state's species considered imperiled or vulnerable–highlight Hawaii (where 63 percent of species are at risk) and California (with 29 percent of species at risk). Secondary centers of rarity are found in several other western and southeastern states, including Nevada, Alabama, Utah and Florida.

The report also looked at species diversity broken down by species categories, which revealed distinctive and at times strikingly different patterns. Diversity for plants and mammals is highest in the Southwest, where many of the states are large and have numerous specialized habitat types. In contrast, amphibians and freshwater fishes reach their highest levels of diversity in the southeastern United States. Bird and reptile diversity is more geographically mixed with both Eastern and Western states represented in the top tier.

Finally, the report assessed how many species within each category are imperiled. The rankings highlight Hawaii, which leads most taxonomic groups, as well as several other Western states.

Imperiled Species: Top-Ranking States by Species Category
RANK PLANTS MAMMALS BIRDS REPTILES AMPHIBIANS FISHES

1. Hawaii Hawaii Hawaii Hawaii California Arizona
2. California Florida Alaska Massachusetts Oregon Hawaii
3. Utah California California Florida Nevada Utah
4. Nevada Alaska Florida Maine Washington Nevada
5. Arizona Georgia Washington California Arizona California

The Nature Conservancy works in all 50 states and throughout Latin America, the Caribbean and the Pacific to protect biodiversity. Conservancy scientists, using data from organizations like NatureServe, conduct comprehensive ecoregional plans to identify threats to species and to determine what conservation activities need to be undertaken to protect them. The Conservancy then works in partnership with communities, government, business and property owners to implement conservation strategies to protect species.

"Ecoregional planning and the protection of whole functional landscapes provide us with the ability to reduce the number of species at risk," said Weekes. "This will not be an easy task, but future generations will judge us on our ability to succeed."