We will look at a potential example of basic research that could be performed by a biogeographer using a real world environmental problem. This week’s assignment will focus on biogeography and the Hispaniolan Ground Iguana or Cyclura ricordii. The West Indian iguanas of the genus Cyclura are the most endangered group of lizards in the world. The Ricord’s iguana, Cyclura ricordii, is listed as critically endangered by the International Union for Conservation of Nature (IUCN). This species is endemic to the island of Hispaniola, and can only be found in limited geographic areas. The range of this species is estimated to be only 60% of historical levels, with most areas being affected by some level of disturbance. The decline in the numbers and distribution of Ricord’s iguana is associated with habitat destruction, competition and predation from feral and domestic animals, and unregulated hunting. The available suitable habitat has been severely reduced by the clearing of land so that it can be used for other purposes. In addition to destroying suitable habitat, this process can also lead to habitat fragmentation. The Rhinoceros iguana, Cyclura cornuta is also found on Hispaniola, often living in close proximity to Ricord’s iguana. This species is classified as vulnerable by the IUCN, but has a much wider range than the Ricord’s iguana. The most recent population estimation is between 10,000 and 17,000 individuals. The impact of competition between these two species is the subject of research currently being conducted.
Biogeographers are especially interested in the distribution of plant and animal species, and in the relationships between plant and animal communities and their natural environments. They seek explanations for the distributions the map reveals. For example, why are certain species found in certain areas but not in others that also appear suitable for them? And why do species exist cooperatively in some places but competitively in others? What is the effect of isolation (for example, on top of a butte or mesa, or on an island formed suddenly when a storm cuts off the tip of a peninsula) on the affected species? How are their interrelationships affected? How do migration patterns change? Biogeography will also be discussed as part of the Austral Realm.