Thank you to Bacopa2@Flickr of northern California for sharing today’s photographs with us. The originals were posted here and here on Flickr, accompanied with some interesting commentary from Bacopa2. Some fine photographs!
The Plant Conservation Alliance’s Alien Plants Working Group has a site featuring the Least Wanted: Alien Plant Invaders of Natural Areas. The 6m to 9m (20ft to 30ft) tall giant reed is listed as one of the many present day undesirable plants. I note “present day” for two reasons: 1) many of these plants were originally (and naïvely) planted for economic reasons, so at one time were desirable; and 2) the changing climate will doubtless induce more scourges in the future.
The University of California, Davis provides one of the most comprehensive factsheets on Arundo donax available online, including this tidbit: “Giant reed is naturalized and invasive in many regions, including southern Africa, subtropical United States through Mexico, the Caribbean islands and South America, Pacific Islands, Australia, and Southeast Asia (Hafliger and Scholz 1981).” Native to the Indian subcontinent, its spread is due in large part to human introduction into the landscape. Why? The Plants for a Future database cites many economic uses for the species, including control of soil erosion, use in textiles and building materials, commercial paper production and even the production of rayon.
Like the worst of many invasives, giant reed can completely choke out and eradicate native plants (and hence native plant diversity); where once dozens of species might have existed in a particular space, only a monoculture stand of Arundo donax might now remain. The local extirpation of native plants negatively affects nearly every other type of organism in the wetland areas it prefers, from fish and reptiles to birds and insects. The UC Davis link above goes into saddening detail on the variety of problems it causes.