Species Richness is affected by latitude through abiotic factors. Species richness is affected by the abiotic factors in every latitude, as Abiotic Factors vary in relation to Latitude.
Ecosystems close to the equator are warmer, more humid, and vary less during the seasons which increases species richness.
Ecosystems far from the equator are colder, less humid, and vary more during the seasons, decreasing species richness.
In aquatic ecosystems, water currents can affect where species are located, so marine species richness trends can vary from the trends for species on land.