Species composition is the number of taxonomic species in a given area and how well each of those species is represented in that area by the number of individuals in its population. The species composition of one area can be compared to other areas. Studies done on species composition over time can help determine ecological changes in each study area.
In regards to freshwater inflows, the chosen indicators’ species composition is often studied before during and after a freshwater inflow event at study sites close to the mouth of the estuary to study sites further away. The species composition over time can indicate how the freshwater inflow events affect the community composition or structure.