Synecology is the study of natural communities (population ecology e.g in a water trophical forest, sea shore, etc). Involves identification of living organisms, studying their distribution, correlating this with physical and biotic factors, studying of behavioural patterns and how organisms interact with one another to form a stable balanced community.
Autecology is the ecology of individual species. About an organisms life in its ecological circle. It is important in building complete pictures of any community, studies on the species habitats, the physical and biotic factors which control its distribution within the habitat, its feeding relationships, life history and reproduction. And its limiting factors within the habitat