Presently more than 250 lakes in North America have become infested with quagga and zebra mussels and this threat has traveled ever closer to Lake County. Is this threat an anomaly and why do we hear more about it now than before?
The fact is that the United States and other countries in the world are being invaded by plants and animals outside their normal range. From boa constrictors taking over Florida”s everglades to aquatic weeds of all types choking waterways, the threat is real and growing. More than half the species on the Federal Endangered species list are there because of significant threats by these alien invaders.
Many invaders, such as wild horses, which impact the desert, have been accepted incorrectly as a native there and vigorously protected by rights groups.
While others such as the starling, a bird native to England, were brought here and set free on purpose. This alien invasion, intended and unintended, has grown to be one of the worlds least known of the major environmental and economic issues, but one of the most severe.
Invasive weeds cost American farmers more than 4 billion dollars a year. The boll weevil is an alien insect costing the cotton industry more than $13 billion. Yellow star thistle, Spanish broom and pampas grass are changing habitats all over the West. Virtually all invasive species are non-native, but not all non-natives are called “invasive species.” They have to cause real trouble to earn that label. Many exotic species serve society and do not cause a problem, such as wheat, soybeans, oranges, tomatoes, rice, apples and most other farmed grains, fruits, vegetables and meat products. Clear Lake is not a stranger to invasive species causing problems, the Asian hydrilla waterweed has choked waterways in Florida and southern States and was probably introduced here by someone emptying a pet aquarium. It costs approximately $1 million per year just to keep Clear Lake from being taken over by this pest.
From Dutch elm disease destroying 77 million American elms and fire ants changing the insect balance to wild pigs rooting up native plants, what makes these invaders so prolific and successful? Alien species introduced here either on purpose or accidentally are outside their natural range where they learned to compete and survive.
In a new environment, these species can reproduce at high rates, may have few competitors or predators and can run wild taking over the new environment. They arrive by ship in containers, bilge water and even attached to passengers. They are sometimes planted in gardens, released from cages or introduced to control other exotics. Many pest problems for the agriculture industry arrived in imported fruit and vegetables.
More than 50,000 non-native species in this country cost more than $138 billion annually in control attempts and this problem is growing at an increasing rate that some scientists call a biological wildfire.
The Great Lakes with more than 58 exotic species introduced from around the world was the port of entry for the zebra and quagga mussels. These mussels out-compete even the exotics and threaten to become the champion of unwelcome and expensive “invasive species” unless we take a different approach to how we contain their movement. But this problem can be solved as well as the trend toward increasing introductions.
A new awareness by governments, politicians, managers, students and the general public to this problem that affects us all will lead to the controls that are needed. For invasive mussels, that control begins with effective boat management and we can”t afford to dally. At a time when a negative economy occupies our attention, protecting our natural resources from invasive species provides a high return for our time and investment.
Jim Steele is a retired Cal Fish and Game scientist, registered professional forester, part-time consultant and a full-time Lake County resident-volunteer.
