Assault of Devilish Grass
By Dr Arvind Kumar
A recent study conducted by ateam led by Seema Mangla, a plant ecologist at Oregon State University, Corvallis, USA, has discovered the prevalence of medusahead (Taeniatherum caput-medusae), a kind of is spreading rapidly throughout the western United States, outcompeting native grasses and even other grass invaders. It is armed with pointed tips so sharp that neither cows nor deer will eat it. The study reveals, “It is a devilish species because it is an invasive grass species absolutely not of any worth, every animal avoids it.” The medusahead’s long, twisting, snakelike seed stems (which give the grass its name) are stiff and pointed like needles. Any animal that leans in for a snack gets jabbed in the eyes and mouth.
The grass is loaded with inedible silica, too, providing few nutrients to would-be grazers. As a result, the grass steadily accumulates, forming mounds of thatch. Seema Mangla opines that ‘it is part of a huge change in vegetation structure,’ as native grasses are overwhelmed by invaders. Other studies have shown that medusahead is spreading at a rate of 12% per year in 17 western states of US. Although it invaded the United States from the Mediterranean in 1880 and is now found only on more than 1 million hectares, scientists worry that it is picking up steam and may be outcompeting not only native grasses, but even cheatgrass (Bromus tectorum), a more nutritious invader. Unless steps are found to control its spread, medusahead is likely to turn millions of hectares of grazing land into worthless fields.
