"Over a hundred definitions of desertification have been proposed, each emphasizing unique issues," he added. "Desertification is complex because there are different factors involved. You can't look at any one thing by itself."
His book notes that a temporary loss of vegetation cover due to short term drought is "distinct from, and not necessarily related to" severe soil degradation and permanent vegetation loss that can result from longer lasting and more severe disturbances.
Written by 45 different authors, the book is the product of an international conference co-organized by Reynolds and Stafford Smith at the Free University of Berlin. Located in a part of Germany's capital known as Dahlem, the workshop brought together scientists from a diverse range of disciplines.
The authors accept the United Nations' view that desertification results from various factors, including natural and human activities. Their book, however, goes further than the U.N. by stressing that humans and natural impacts are always coupled.
"There are always human and environmental drivers," Reynolds asserted in his interview. "If you don't consider the human dimensions and the biophysical dimensions simultaneously, you're going to miss the boat."
Reynolds described a hypothetical dry land ranching family that starts out owning a modest-sized herd of cattle grazing in an area with good soil and grass cover. If a drought suddenly sets in, grass output may decrease enough to force that family to sell some cattle in order to pay its bills. If cattle prices then drop, the family goes further into debt.