Holism
Holism does not base its claim to protection on the welfare of individuals and the potential harm they could suffer from the loss of other species. Instead, various higher-level entities, such as species or ecosystems, are also ascribed an intrinsic value, which is often based on their system character or their own species-specific interests, which differ from individual interests. In this view, biodiversity can therefore be understood as something intrinsically valuable and worthy of protection.
Some of the best-known representatives of holism include:
Callicot, J. B. (1989). In Defense of the Land Ethic: Essays in Environmental Philosophy. SUNY Press.
Leopold, A. (1949). A Sand County Almanac. And Sketches Here and There. Oxford University Press.
Rolston, H. (1975). Is There an Ecological Ethic? Ethics 85, 93–109.
A good general overview of the various currents in environmental ethics can be found in:
Krebs, A. (Ed.). (1997). Naturethik. Grundtexte der gegenwärtigen tier- und ökoethischen Diskussion. Suhrkamp.
Krebs, A. (1999). Ethics of Nature. A Map. Walter de Gruyter.