1994, Hughes put forward that "environmental history, as a discipline, is a discipline to study how human beings relate to nature from ancient times to the present, and as a method, it is to apply the principles of ecology to history" [1]; In 200 1 year, he proposed in "World Environmental History: the Changing Role of Human in Life Communities" that "the task of environmental history is to study the relationship between human beings and their natural communities from ancient times to the present, so as to explain the changing process affecting this relationship. As a method, environmental history regards ecological analysis as a means to understand human history "[2]; In 2005, he put forward in "Mediterranean Region: An Environmental History" that "environmental history, as a discipline, is a discipline to study the environmental interaction between human beings and social and natural since ancient times, a method and a means to understand human history by using ecological analysis." [3]
[1]J. Donald Hughes, Pan's Journey: Environmental Problems in Ancient Greece and Rome, Baltimore and London: Johns Hopkins University Press, 1994 P3.
[2] J. Donald Hughes, "World Environmental History: Changes of Human Role in Community Life", Changes of Human Role in Community Life, London: routledge Press, 200 1 P4.
[3] J. Donald Hughes, Mediterranean: Environmental History, Stabbara, California, P 15.