Non-Native Goats and Iguanas threaten Pacific Islands

Summary: Two papers on non-native goats and iguanas, that were brought by humans to several Pacific Islands, were made to encourage people to remove or exterminate these two species. One paper said that the goats were overgrazing and decreasing the amount of grass available in the ecosystems. It also talked about the negative effects the iguanas were having on human activity including more car and road accidents from iguanas crossing the roads. Both papers warned that the goats will also have a role in destruction of habitat from over grazing and "recommends that the goats be removed from some of the vulnerable ecosystems in the Pacific." The iguanas are also reported to have possibly been on the islands since the 1950s and have now experienced a spike in population. This has lead to displacements of native species on the islands, particularly in Fiji. The biodiversity of the ecosystems on the islands has also depleted because of the iguanas and goats because they have destroyed habitats and replaced native species as well. But the main point that these two papers wanted to make, was that invasive alien species need to be removed from vulnerable islands or prevention from introduction of invasive species is key to vulnerable ecosystems on these islands.

Relation: In our ecosystems unit we learned about the impacts and negative effects invasive species have on ecosystems, and this is an example of these negative effects in several ecosystems. Because of the goats many species of plants (especially grass) have depleted because of over grazing from the goats, which would lower the biodiversity of the ecosystem. The iguanas have also depleted species of native animals from the increase in population, this was most likely cause by competitive exclusion. Since there was a spike in the iguana population, then they would need more food resulting in less food for other native species with the same food source as the iguanas. This would cause a decrease of growth in the native population, with the iguanas out competing the native species. The iguanas have also contributed in the process of decreasing the biodiversity of the islands' ecosystems. This article is an example of how invasive species can effect an ecosystem's biodiversity and how competitive exclusion can also contribute to the loss of biodiversity in an ecosystem.

Link: http://www.scidev.net/global/biodiversity/news/non-native-goats-and-iguanas-threaten-pacific-islands.html

Labels: ecosystem, biodiversity, competitive exclusion, native species