• Species richness is the number of different species in a particular community (and not the total number of Individuals in each species).  
• Species diversity is a measure of community complexity. It is a function of both the number of different species in the community (species richness) and their relative abundances (species evenness). Larger numbers of species and more even abundances of species lead to higher species diversity.  A forest community with 20 different kinds of trees in even abundances would have greater species diversity than a forest community with the same number of species in very uneven abundances (for instance, with 90% of the trees belonging to a single species). 
• Abundance refers to a quantity but does not specifically describe the number of species or individuals in a community. 
• Resilience describes an ability of an ecosystem to withstand and recover from a disturbance. It does not describe the number of Individuals or species in an ecosystem. 

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