Introduction
Exotic snakes are invasive type of snakes which have been introduced in the United States from their native habitats through different means. Besides snakes, there are other species of plants and animals which have found their way to the US through a wide range of ways most of which are human related activities. Common exotic snakes in the US have been introduced accidentally through stowaways on planes and ships when moving from one country to another.
Why should Americans be concerned about these exotic species of animals and in particular snakes? Research has found out that exotic snake are a threat to not only indigenous species but also to forests, agriculture and the entire environment. It is more obvious that exotic snakes compete for resources with native species once they are introduced in the habitat.
Other invasive snakes feed on the native ones and even parasitize them hence making them endangered (Simberloff, 1992). This research paper addresses the effects of these exotic species of snakes in the United States with special and analytical focus on agriculture, forests, and other animals.
Literature Review
The concept of invasive species has received manifold attention among many American leaders and researchers due to the threat they have on fauna and flora. These individuals have dedicated their resources and time to find out the major effects of invasive snakes in the American habitat and why stronger legislation and efforts are needed to control the menace.
In their 1999 research and publication, Badger and Netherton (1999) gave a detailed coverage of the effects of snakes to the habitat together with the ways in which some snakes are getting endangered mainly because of human activities. Among these species affecting American is the Brown Tree Snake which is believed to have been introduced in the country after the Second World War.
Brown Tree Snake
The snake got to America through a ride on a military cargo that was moving from New Guinea. Since its introduction at the Guam Island, its population has exponentially grown reaching approximately 13,000 snakes per square kilometer (Badger & Netherton, 1999). Many would consider this to be a good investment for museums and animal orphanages in the regions, a contradiction of what recent research indicates.
Effects on other Animals
Brown Tree Snake is known to prey on other animals like bats, lizards and frogs among others. Researchers concur that a good number of animal species have become extinct as a result of the ever increasing population of exotic snakes in parts of the U.S. like Guam. It is believed that up to ten species of exotic lizards in Guam have been eliminated leaving the region with close to three species.
Besides lizards, flightless rails have also suffered similar attacks resulting into fears of extinction of most of animal species in the island (Badger & Netherton, 1999). According to the U.S. Congress, Office of Technology Assessment, there are numerous invasive species of snakes threatening the survival of several bird species in the country.
Predation of snakes therefore has continuously led to the extinction of these species most of which have significant economical importance to Americans in terms of tourist attraction. Birds and some lizards are well known for their major role in plant pollination. With a reduced number of these agents within an ecosystem, the regeneration of plants is significantly affected resulting into poor plant coverage in affected regions (U.S. Congress, Office of Technology Assessment, 1993).
During the 1993 research, the U.S. Congress, Office of Technology Assessment report indicated that several exotic snakes had become a significant threat to many Americans with young children being considered as major victims. Although the Brown Tree Snake has mild venom, the snake has been reported to attack children in parts of Guam. Based on these findings, one out of a thousand patients admitted in emergency hospital rooms is usually as a result of snake bites.
Besides the risk of being bitten by snakes, regions with high populations of exotic snakes record higher disease outbreaks. This is due to the fact that some of the disease carriers were initially controlled by native lizards and other animals which have faced extinction. A good example is dengue fever whose main carrier is mosquitoes that were initially fed on by native lizards which have faced extinction (U.S. Congress, Office of Technology Assessment, 1993).
Effects on Agriculture
According to Simberloff (1992), there are thousands of plants and animals species which have been established in the country since the colonization era hundreds of years ago. In his 1992 survey, he argued that some of the foreign plants and animals introduced in the country have turned out to be a threat to native fauna and flora, a phenomenon which has become tragic to farmers and the entire agricultural sector. Many of the animals are diseases carriers and agents.
Simberloff (1992) further noted that these species of invasive snakes were disastrous in areas where their population was high than normal. Destruction of farms, blockage of waterways and electric interruptions are some of the devastating effects of exotic snakes (Simberloff, 1992). Agricultural research has similarly reported that the famous brown tree snake is an agricultural pest that has negatively impacted the sector for years.
There are several insects in places like Guam which were initially controlled by native lizards and birds which have since been eliminated by exotic snakes. As a result, Guam experiences a lower production of fruits and vegetables due to pest infestation and expensive chemicals means that have to be employed in controlling them.
Since early 1945 when the snake was first introduced in Guam, the island continuously suffers agricultural decline as a result of ever increasing animal parasites and crop pests (U.S. Congress, Office of Technology Assessment, 1993).
Besides the above discussed effects of exotic snakes on agriculture, Brown Tree Snake and other species are a threat to fish farming and rearing of birds. Many of these species feed on fish and birds reared by individuals residing in areas being inhabited by exotic snakes. This has caused economical loss to farmers and a net loss to the national economy since fish farmers get discouraged to rear fish in areas prone to Brown Tree Snakes.
Consequently, the need to import poultry from other states and countries in order to meet the needs of Guam people who never experienced the shortage before the introduction of these exotic snakes has increased. More expenditure is therefore spent on importation and control of crop pests and animal parasites which would otherwise be controlled by biological means (Simberloff, 1992).
Effects on Forests
Like agriculture and animals, forests in the United States experience devastating impact emanating from the introduction of exotic snake species in the country. With recent research findings indicating that invasive snakes were posing a threat to American ecosystem, a close look on how this has affected the distribution of certain tree species in the country has also been considered.
Although some of the impacts being experienced could be indirect, it has been conclusively agreed that exotic snakes are disastrous to thousands of tree species in America. While birds add up to a smaller percentage of the total forest coverage, their role in any ecosystem is immense (U.S. Congress, Office of Technology Assessment, 1993).
As mentioned above, the introduction of Brown Tree Snakes has led to the extinction of several bird species in many parts of the United States through predation. Accordingly, forests are left with low population of birds that cannot facilitate processes like pollination, seed transfer and control of pests which feed on certain tree species. According to experts, the low population of native birds has exposed the sector to two major factors which are quite fundamental in forest expansion.
The absence of birds which are known to facilitate the process of germination has caused stunted population among certain native trees (U.S. Congress, Office of Technology Assessment, 1993). In addition, there are animals which feed on seeds and fungi that attack most tree seeds in a forest.
The population of seed fungi and predators is usually high within the surrounding of a tree; as a result, trees rely on native birds to disperse seeds to far places that are free from predators and fungi. With diminishing number of birds, seed survival has dropped leaving most trees at the mercies of fungi (Calow, 1998).
Conclusion
Exotic snakes cause severe effects on agriculture, forests and other animals in the United States. Since the introduction of these species, hundreds of bird species have faced extinction together with other animals like lizards, frogs and fish.
Equivalently, distribution of trees in forests has been hampered by inadequate number of native birds which facilitate processes like pollination, germination and seed dispersal. Human beings have also been exposed to health hazards like mosquitoes and snake bites among others. Efforts and legislations have to be put in place to control introduction of more exotic snakes in America and to reduce the population of existing ones.
References
Badger, D. & Netherton, J. (1999). Snakes. Stillwater. Minnesota, United States: Voyageur Press.
Calow, P. (1998). The encyclopedia of ecology & environmental management. New Jersey, NY: Wiley-Blackwell.
Simberloff, D. (1992). Impacts of Introduced Species in the United States. U.S. Global Change Research Information Office Vol. 2, No. 2. Web.
U.S. Congress, Office of Technology Assessment. (1993). Harmful Non-Indigenous Species in the United States, OTA-F-565. Web.