By Bill Kunze, Pennsylvania State Director, The Nature Conservancy

The ash tree, a stately specimen that gives our neighborhoods shade and whose wood provides the summertime cracks of baseball bats, is suddenly threatened by a beetle that is no larger than the face of a penny. A thumbnail-sized mussel now endangers the plentiful game fish and other aquatic life of the Susquehanna River.

This summer's discoveries in Pennsylvania of the emerald ash borer and the zebra mussel (animals native to Europe and Asia) remind us of the growing threat posed by invasive species -- nonnative plants, animals, and microorganisms that spread rapidly and aggressively when introduced to areas beyond their normal ranges.

The Pennsylvania Department of Agriculture recently announced that the emerald ash borer has been found in the state for the first time and immediately placed a quarantine on wood products (including nursery stock and firewood) from four counties in western Pennsylvania. The discovery of the beetle came within days of confirmation that zebra mussels are living in a Tioga County lake. This is the first time these troublesome shellfish have been found in Pennsylvania's portion of the Susquehanna River watershed.

Each of these discoveries, taken alone, is cause for grave concern. The emerald ash borer has been blamed for killing more than 20 million ash trees in the Midwest. Its larvae attack 12 species of ash trees, including white ash, a commercial timber species valued for furniture and flooring, and green ash, a common tree along city and suburban streets.

Zebra mussels already cause problems in western Pennsylvania, where industries and municipalities must pay to clear clogged water-intake valves. They also have a dramatic impact on ecosystems by consuming plankton that provide the base of the food chain for many native fish.

But serious as they are, these two pests are just part of a broader onslaught of invasive species that are spreading around the world at an accelerating rate, taking advantage of dramatic increases in global trade and travel. Invasive species have contributed directly to the decline of 42 percent of threatened and endangered species in the United States. More than 400 nonnative insects and microorganisms are permanently established in North American woodlands. More than 170 nonnative aquatic species have been introduced to the Great Lakes, most of them since the St. Lawrence Seaway opened in 1959.

The annual cost to the United States economy is estimated at $120 billion a year.

Even Pennsylvania's state tree, the hemlock, is under attack from one of these invaders. Throughout the mid-Atlantic, an invasive insect called the hemlock woolly adelgid is devastating these trees.

We can and should do more to stop these pests from entering the country and to rid our lands and waters of those that are here.

Congress is considering legislation to prevent infestations of aquatic nuisances such as the zebra mussels, which likely were introduced to this country when oceangoing ships released infested ballast water into the lower Great Lakes.

Now being considered by the House of Representatives, this legislation addresses the need for early detection of and response to nonnative species and establishes an important national goal: an end to all invasive species introduction through ballast water by 2015. Congress should further strengthen this legislation by adding provisions to review intentional imports of aquatic species and prevent those imports if those species, such as the snakehead fish and several species of Asian carp, would be invasive here.

To fight invaders that are killing our trees, Congress should increase funding for the U.S. Department of Agriculture's Emerging Plant Pest program. Equally important, the USDA should move forward aggressively to revise regulations that are supposed to protect our trees from these invaders -- regulations that were proposed for revision in 2004 but have languished since.

In Pennsylvania, the Governor's Invasive Species Council was created in 2004 to develop and implement a comprehensive invasive-species management plan for the state. One of the priority objectives identified by the council is to work with the governor, the Legislature and other key partners to establish permanent money for invasive species management.

Individuals and businesses can also help stop the introduction and expansion of these species by more carefully managing their activities that help the pests spread.

For example, the emerald ash borer likely arrived in the United States inside the wood-packing crates that accompany most shipped cargo. By switching to plastic pallets or by treating the wood pallets to kill potential invaders, we can reduce this threat. Boaters could help by washing their boats and trailers when moving from one body of water to another. Firewood should be purchased and used locally, not moved from place to place.

But individual action alone will not stop this costly trend. Our greatest opportunity to reduce the harm wrought by invasive species is to prevent them. Congress must give agencies the authority and resources to act to stop the introduction of invasive species into the United States.

For more information, visit The Nature Conservancy in Pennsylvania webpage.

Link: The Nature Conservancy – Celebrating 50 Years in Pennsylvania

8/3/2007