As if drought stricken, over-crowded California doesn’t have enough problems. Now, a new species of tumbleweed is rapidly spreading across the Western state, threatening local wildlife and plants. Invasive species have a nasty habit of disrupting local ecosystems by displacing vital plants or animals and consuming resources. Further, such local ecosystems are not adapted to the new species, populations can quickly grow out of control.
The plant in question is actually a hybridization of two invasive species of tumbleweeds, creating a sort of “super” tumbleweed. Called “Salsola ryanii”, the species was first discovered in 2002 in two separate areas of California’s central valley. The species has since spread throughout much of the central valley and has even been found in San Francisco, in the coastal areas, and also in the Ventura area in the south. This was confirmed by a study in 2012.
Such rapid growth suggests that the invasive species may spread uncontrolled not just throughout California, but that it could also head eastwards. Worse yet, efforts to contain the invasive tumbleweed were limited as experts did not believe that the plant would spread very far.
A combination of Salsola australis and Salsola tragus, the tumbleweed has been tumbling far and wide, spreading its seeds as it does. Salsola australis is already found throughout California and Australia and is believed to have originated in either Africa or Australia. Salsola tragus extends throughout 48 states, but is native to north Africa, Western Russia, and everywhere in-between.
Researchers are still trying to figure out what is fueling the rapid expansion of the tumbleweed. Tumbleweeds expand their range by dropping seeds as they tumble.
So far Salsola ryanii has proven to be spreading far more rapidly than other types of tumbleweed, worrying scientists even more so than usual. The rapid expansion comes as a surprise for many experts in the field.