Arundo Donax as an Invasive Species An invasive species is a species of plant or animal that was introduced to a new habitat by humans, intentionally or otherwise. Invasive species are also defined as being harmful to the environment and ecosystem to which they are introduced, frequently changing the nature of the system (What is an Invasive Species? 2015). Arundo donax is one such species. It is a plant similar to reed or bamboo in that it is tall and straight in appearance. While Arundo donax is a dangerous species of plant that can severely harm native wildlife, it can also be beneficial to the area as a whole.
Arundo donax is an invasive species that is part of the Arundinoideae subfamily. It is similar to other types of cane not only in looks, but also how it spreads. It uses a fast growing root system that is one of the best in the world to quickly spread to surrounding areas (Thomas D. L. , 2008). Arundo donax has shown it can adapt to a large variety of living conditions ranging from its native tropical-subtropical environment in the Mediterranean Basin to the desert climate found in the United States. It has also shown an extreme resistance to large concentrations of metals, such as arsenic, cadmium and lead, in the soil.
While it is able to survive in the soil with high metal content, some of the plant still becomes contaminated. Where as in more reasonable, but still high, concentrations it is able to grow without becoming contaminated inside the plant at all . (GUA Zhao-hui, 2010). The Arundo donax species originated in the warm tropics and subtropics of Middle East Asia and the Mediterranean Basin. There is also evidence to suggest that it was introduced to Eurasia from the Indian subcontinent. It was originally introduced to California and planted in the Los Angeles River where it was harvested for use as building materials (Thomas D. L. , n. d. ).
Due to California having a similar climate to its native environment, the Arundo donax planted there thrived and quickly spread. It is currently present in 23 states, mostly the southern half of the United States while also including Washington and Michigan (Species Profiles:Giant Reed, 2015). It is also present in parts of New Zealand, where it has been placed on the unwanted organism list and made illegal to sell and distribute the plant (Species Profiles:Giant Reed, 2015). Arundo donax causes many large changes to the environments to which it is introduced, some positive, some negative.
Arundo donax is a very flammable plant. This is mostly due to it producing a larger amount of dead biomass than most other native plants, such as herbaceous or wood based plants. The dead biomass comes mainly from parts of the plant that die, either from getting damaged or removed from the root system. In many of the locations in which it grows, it greatly increases fire risk by making the area more flammable, provides more sources of ignition, increases fire intensity and spread rate (Giant reed, 2009).
In the likelihood of a fire, which will be not only more likely but also more destructive due to the spread of Arundo donax, large areas can become almost completely devoid of plant and animal life. Fire doesn’t suppress the spread of Arundo donax very much due to its large root system. So even in the case of a fire, it can quickly restore itself to its former state. A positive change Arundo donax brings to locations to which it is introduced is an increased amount and quality of soil organic matter. Over time soil health can degrade as the amount of organic matter lessens and the land succumbs to desertification (NAVEH, 1974).
Arundo donax helps with this naturally over time as parts of the plant die or are destroyed, but where it really shines is when it is being farmed. Arundo donax when farmed, due to its large amount of biomass and low tilling intensity required, will over the course of several years significantly increase organic matter content in the soil. Arundo donax can be one of the more effective plants for this purpose due to its fast growth rate. When the Arundo donax infects an area it is able to cause massive changes in the ecosystem of the native flora and fauna.
Plants are the ones effected the most when Arundo donax establishes itself in an area. Due to the Arundo donax’s ability to grow from just a small part of a stalk, it can completely take over an entire region from just a piece of the plant landing there, spreading through it like wildfire. Because of the fact that it has very few natural enemies in its new environment it grows nearly completely out of check, using its extreme growth rate to completely outcompete other plant life, monopolizing large parts of available water and other resources.
Also blocks out the sun potentially harming the plant life as well. Most native animal species are affected largely by Arundo donax being introduced to their environment as well. Some species, such as the Arroyo Toad or Least Bell’s Vireo are effected extremely negatively by Arundo donax growth. The Arroyo Toad is an endangered species of toad that prefers environments very similar to that of Arundo donax, which are riverbanks and other wetland areas. When Arundo donax grows in an area where Arroyo Toads inhabit, the river flow can be interrupted and redirected.
This is due to the complex root systems forming on the riverbank and moving in the way of the flowing water. When this happens, rivers can go from being wide and shallow, the preferred breeding habitat of the Arroyo Toads, to deep and narrow, which is a suboptimal breeding ground for the toads and has been shown to reduce population size. Because Arundo donax plants typically have very thick stalks that grow extremely bunched up and close together along the riverbank, it can severely interfere with the movement of the Arroyo Toads, effecting the toad’s ability to catch food such as insects.
The Arundo donax litter is not a good enough food replacement for the plants that it eliminates when growing, resulting in less aquatic insects in or close to these areas. Because of this lack of food that serves as the main source of nutrition for the toads, some of them can end up starving, reducing the population further. Although the plant litter does enable more ants to thrive, they are only an adequate food source for toads in the tadpole stage, becoming ineffective once the toad has grown further. The Least Bell’s Vireo is an endangered songbird native to North America.
This species of birds live almost ex (Jason Giessow, 2011). Due to how much Arundo donax is able to negatively affect the environment or land on which it is planted, there are frequent attempts to remove it. Because it does not use seeds to spread, removal attempts are often effective, but possibly expensive, however, if it is not removed quickly then there is a possibility that it will spread across a very large area, becoming extremely expensive and unfeasible to eliminate. For smaller areas where Arundo donax has grown, manual removal is a sufficient and frequently used method.
Using manual methods, such as hand pulling to remove the shorter stalks and using a tool such as a mattock or shovel to remove the taller stalks along with the deeper root system is effective, however it can damage the land while also making it more difficult for the flora and fauna to reestablish themselves (Thomas D. L. , n. d. ). This is also the issue with using mechanized tools, such as tractors or excavators, with the additional risk of missing a part of the root, enabling the plant to regrow. The Arundo donax is a harmful species of plant originating in the Mediterranean Basin and Middle East Asia.
Due to the similar climates and versatility of the plant it is able to spread quickly, eliminating and harming many native species. It brings large changes to areas it manifests in, both good and bad, with increased fire damage being a negative change and better soil health being a positive change. Removal of Arundo donax can be effective in small areas, but can quickly become unfeasible to remove. As a consequence of this versatility and extremely fast growth, it can have a severe effects on the native flora and fauna.