tem values provides greater justification for the conservation of ecosystems. A corollary of this observation is the point made by Aldo Leopold that the first rule of a tinkerer is to not throw away any of the parts. The ecological engineer is nature's tinkerer.
Ecological engineering is not the same as environmental engineering, a respected field that has been well established in universities and the workplace since the early 1960s and was called sanitary engineering before that. Environmental engineers are certainly involved in the application of scientific principles to solve pollution problems, but the concepts usually involve energy and re-source-intensive operations such as settling tanks, scrubbers, filters, and chemical precipitators. Certainly, some techniques such as trickling falters could be considered ecological engineered approaches when they were conceived, but the field has gone far beyond designing ecosystems. It is certainly possible that ecological engineering will develop in a partnership with environmental engineering, but the two fields remain distinct today. For interesting discussions of the differences and similarities between these two fields, see McCutcheon and Walski (1994), Mitsch (1994), and Odum (1994).
Ecological engineering and its synonym "ecotechnology" should also not be confused with biotechnology, which involves genetic manipulation to produce new strains and organisms to carry out specific functions. Some of the differences between ecotechnology and biotechnology relate to their basic principles, control, design, and ultimate possible costs to society (see Mitsch and Jørgensen, 1989b). Nevertheless, a comparison can be made between the development of ecotechnology and biotechnology. Ecotechnology is almost at the stage where biotechnology was 20 years ago. Molecular biology was just beginning then to establish the basic science and techniques for the yet unborn field of biotechnology. Today, ecology is recognized as a fundamental science and is now developing the ecosystem-level tools to develop the field of ecotechnology. Despite the progress made in biotechnology (usually involving genetic manipulation of species), many researchers and environmental managers believe that it will not be a major factor in solving the world's environmental problems and that there may be some adverse environmental consequences from its development. Ecotechnology, which uses the existing array of species, communities, and ecosystems of the earth, may receive more attention as limitations of biotechnology are experienced.