Along with the development of the science of ecology, a series of branch sciences have been formed at present. Today,the ecology is not a single science, but a group of sciences-system of sciences. There are at least more than 100 sciences with their names containing "eco" . So emerges the necessity to classify the large number of ecological sciences.In our view, considering the nature of object and scale of study, and accordingly the methods which have to be adopted in investigation,as well as the trends o...