As the cold weather reduces the aquatic weeds nuisance at Clear Lake, a number of people are wondering what will happen next spring. Without question the weeds and algae will return.
How much of a problem they will be remains to be seen. If the water is clear during the early spring months, it”s a sure bet the weeds will return in huge numbers. As for the algae, it could be either as thick as this past summer or less. It all depends on the nutrient loading.
The Board of Supervisors (BOS) has appointed a steering committee to look into possible funding and solutions to control the weeds and algae. George Speake, a member of the steering committee, told the BOS last week that the county should allocate $500,000 a year to address the weeds and algae problems. The committee outlined other steps to control the weeds and algae.
I know the public is tired of hearing the word “study” but that is what needs to be done. What is causing the nutrient loading? Is it septic systems flowing into the lake, is it the runoff from agriculture, or is itsomething else? These questions need to be answered before a lot of money is spent attempting to control the weeds and algae.
Of course, it isn”t just the algae and aquatic weeds that cause havoc in Lake County and other parts of the state. There are hundreds of species of other invasive weeds that threaten local woodlands. The lake is home to an estimated 35 different species of weeds of which at least one-third are non-native or what are called “invasive weeds.” But not all the invasive weeds are in the lake. In fact, the county is literally being overrun with non-native weeds and if they”re not controlled soon, it could mean thousands of taxpayer dollars spent in the future.
Some of the more invasive plants in the county are the yellow star thistle, French and Spanish Broom, salt cedar (tamarix) and arundo. All are widespread throughout the county and are causing real problems for humans and wildlife.
The yellow star thistle is the most abundant invasive weed in the county. It is a native of Eurasia and was introduced into western North America in the mid-1800”s. California has more star thistle than any other state, with about 15 million acres infested with the weed. In Lake County alone there are thousands of acres that are covered with star thistle and the weed continues to spread. Vehicles that pick up the seeds in their tires often spread the weed. In fact, star thistle can even be found in the more remote sections of the Mendocino National Forest.
The mature plant is gray-green in color and grows to a height of 1-3 feet. Yellow star thistle is an invasive competitor to desirable plants in ranges and pastures. It can crowd out grasses where soil moisture is limited or where grazing has weakened forage. Where this weed is well established, its sharp spines may exclude livestock from grazing on any grasses growing beneath the star thistle plants. Yellow star thistle produces a toxin that causes death in horses through an illness called “Chewing Disease,” which makes it impossible for the animal to swallow. The plant has little or no nutritional value to wildlife. Actually, star thistle will crowd out native forbs and other plants that deer and other wild animals eat.
The hot and dry summers in Lake County are perfect for star thistle. The plant is also extremely hardy and about the only way it can be controlled is either by a strong herbicide or burning. The plant originally came from Turkey and most likely arrived by ship. In its native land there is a beetle that feeds on the flower of the plant, which in turn controls it. However, there are no natural controls in United States.
French and Spanish Broom are also causing all kinds of problems. These plants can grow to heights of more than 6 feet. These plants are also non-native and were probably introduced as decorative plants for gardens. French Broom flowers are also used as a yellow dye for fabrics.
Salt cedar (tamarix) has replaced willows and other native plants on the shores of creeks and in wetlands. The plant uses up water and in many areas the creeks are drying up.
Of course, on the horizon is the possibility that quagga mussels will eventually find their way into Clear Lake. Invasive weeds or other unwanted species, whether in the lake or on the land, are just another reason why we have to be diligent on what comes into the county and to protect our beautiful area.
