The definition of conservation goals is a complex task, which involves both ecological sciences and social values. A brief history of conservation strategies in Germany (protection of cultural landscapes), United States (wilderness ideal), and southern Chile (preservation paradigm and the more recent interest in ecotourism) illustrates a broad range of conservation goals. To encompass such an array of conservation dimensions and goals, the ecosystem approach adopted by the Conference of the Parties of the Convention on Biological Diversity represents a good approach. However, to become effective, this kind of approach requires clarifying and agreeing upon basic concepts, such as ecosystem. To serve that purpose, we present a scheme that considers the selected phenomena, internal relationship, and the component resolution to define an ecosystem. We conclude that: (1) conservation traditions encompass interests in the preservation of both natural and cultural heritages, which also appear as mutually dependent dimensions. Hence, nature and humans are brought together as much in the goals as in the processes of conservation. (2) In the context of current global change, it is impossible to completely "isolate" protected areas from direct or indirect human influences. In addition, the current view of nature points out that biotas and ecosystems will change over time, even in protected areas. Hence, in order to preserve species or habitats it is not enough to isolate protected areas, but it often requires active management and conservation actions. The two former conclusions suggest the need to revise the conservation approach that has been undertaken in the southern region of Chile, because (a) local people have been systematically excluded from protected areas, and (b) these areas lack personnel and facilities to conduct appropriate conservation and/or management programs. (3) Our analyses of the views of nature and conservation goals in different regions and/or historical moments demonstrate that these involve not only scientific criteria, but also philosophical, political and broader cultural, social and economic dimensions. Hence, effective conservation requires a greater degree of interdisciplinary and interagency cooperation