Few would dispute the assertion that research into the problems of arid lands should have a firm ecological base. But "ecological" in practice is given different meanings in different programs. Though derived from the Greek oikos, which meant "dwelling" and extended to mean "environment," it was coined a hundred years ago to denote a new focus of interest in the natural sciences. This usage is understandable, now we recognize that most scientific endeavour has been conducted within an anthropocentric paradigm which militates against attention to human activity as an equal component of ecosystems.