Community structure refers to the composition and organization of a biological community, primarily focusing on the relationships and distributions of different species within that community. The number of species present, known as species richness, along with their relative abundances, is a fundamental aspect of community structure. These two characteristics provide insights into the biodiversity of the community and how species coexist and interact with each other.
While species migration patterns, predator-prey interactions, and environmental factors such as climate and soil composition are important in understanding ecological dynamics, they relate more to processes and influences affecting communities rather than directly describing their structure. Therefore, the number of species and their relative abundances is the key attribute that defines community structure.