Biodiversity. The word evokes the splendor of a great forest, or the teeming richness of the ocean, and is simply defined as the variety of organisms in an ecosystem of interest. To protect biodiversity, scientists must be able to measure it. This means figuring out how many different species are living together in a particular space. What is a convenient way to count species?
Trying to count everything in an entire ecosystem would be impossible, so scientists use a tool called the quadrat, which is a frame of fixed size placed randomly in the environment in which to do the counting. After cataloging the species and individuals found in this small section, the process is repeated, placing more quadrats at random, or alternatively, at set positions along a line through the environment, referred to as a transect.
In order to then estimate the total number of species in an area, species accumulation curves are used. If the cumulative number of species found in a quadrat are plotted against the number of quadrats sampled, a curve will emerge. For example, in this data set, when four quadrats were investigated, it was found that there were 10 unique species. Six contained 17 and so on.
