Question

1.Why do you think that, at global scale, the story of damaging wildlife is really the story of exotic invasive species? 

2.What do you see as the long term impacts of damaging species on the ecosystems of North America? Explain. Give examples.  

3.Do wildlife diseases impact endangered species? Explain. Give examples. 

4.Are traps lethal or non-lethal devices? Explain your answer, use specific examples. 

5.How important is the experience of the practitioner in using traps or snares to catch a coyote? Explain. 

Answer 1

Exotic species are the alien species of plant/animal to an environment. Introduction of these alien species in an environment can be intentional (anthropogenic) or an accident. E.g. Brown tree snake is an exotic alien species in the island of Guam.

These exotic species proliferate in the new environment in the absence of any natural predator and thus multiply and do irreversible damage to the local ecosystem. They are often considered responsible for the extinction of many species of native animals throughout the globe. This complete process of invasion of a species in an ecosystem and the consequential decline of native species which eventually ends up in extinction of the native species is termed as a biological invasion.

These invasive species are identified by their traits such as extremely rapid growth, tolerance to a variety of environmental condition (hardy variety), high phenotype plasticity etc. These features lead them to outperform the endemic variety in the native environmental condition. As a result of this, exotic varieties proliferate at the cost of endemic species.

The whole process of biological invasion and its effect can be summarised by a reference to the introduction of Mongoose to the tropical islands of the Caribbean and other plantation islands. Mongoose is native to African subcontinent. They have been responsible for the extinction of a large number of endemic vertebrates, livestock species and cause of livestock disease on these isalnds. Same is the case with Burmese python in the state of Florida. Burmese pythons are considered to be invasive species in Florida which poses a significant threat to many endemic species which includes alligator.

If the threat of the exotic species crosses a threshold beyond which the native species cannot recover, the endemic species go extinct. The threat of biological invasion is not limited to a particular region but all over the globe. It is proved by the figure of IUCN which states that globally around 42% of endangered or threatened species are at risk due to biological invasion by exotic species.