The land ethic, primarily functioning as an ethical approach to environmental problems identified in Aldo Leopold's classic book, A Sand County Almanac, is one of the foremost pioneering and inspiring attempts to formulate environmental ethics. Leopold's land ethic is to a large extent based on the community concept in ecology. For instance, the premise of the land ethic is that the individual is a member of the land-community of interdependent parts. And the maxim of the land ethic also draws attention to the need to preserve the integrity, stability, and beauty of the land community. The community concept, representing a holistic paradigm holding that biotic communities are integrated and stable, has become problematic since in the late 1940s; a number of individualistic ecologists, such as H. A. Gleason, started arguing that plant associations do exist, but that these eco- groupings are too loosely related to constitute an integrated and stable community. Against this background, the aim of this paper is threefold:(1) to briefly show Gleason's individualistic argument and how it would affect the land ethic;(2) to argue that Gleason's individualism will raise, at least, a threefold problem for the land ethic, including (i) how to incorporate ever- developing sciences within the land ethic, (ii) how to engender duties from ever-changing communities, and (iii) how to modify the maxim of the land ethic; and (3) to argue that Leopold's adaptive scientific epistemology, the affirmation of eco-relationships, and a new formulation of the maxim can be replied to the problems raised by Gleason's individualism.