What factors affect species diversity in an area?
Species diversity, often referred to as species richness, is the measure of how many different types of species, and how evenly the number of individuals of each species is distributed throughout a community. Today, four main hypotheses exist to explain which factors impact the diversity of species within a community:
- The area’s productivity plays a huge role in determining how many different kinds of organisms survive in one area. Communities that support many producers commonly attract more herbivores, which in turn entice predators, parasites and scavengers. As these populations increase, competition becomes common, and species will begin to adapt into specialists of those areas. As more specialist species arise, the diversity of the area increases. As speciation occurs, extinction rates also tend to decrease because the organisms are more suited for their environment
- In a similar hypothesis, energy input, rather than productivity, is said to define the diversity of an area. High temperatures and longer exposure to sunlight not only increases productivity, but also makes it easier for organisms to tolerate the physical conditions of the environment. This, again, leads to speciation and low extinction.
- The history of an area could also distinctly determine its species diversity. Regions closer to the equator were not covered in ice during the historical climate changes, and it has also be speculated that the land area in the tropics have been significantly larger than what is available at other latitudes. Areas with a history of less dramatic change and more favorable conditions will have higher diversity rates.
- In the Intermediate Disturbance Hypothesis, experts suggest that habitats that experience regular disturbances, moderate in their severity and frequency, will have the greatest diversity. Regions with mid-successional communities tend to allow for more types of organisms to thrive as opposed to pioneer or mature communities.