ALN logo; link to Arid Lands Newsletter home page No. 59, August 2007
What's so special about drylands?

Editor's note:
How DO we know what's so special about drylands?

As noted in our last issue, 2006 was designated by the United Nations as the International Year of Deserts and Drylands. The IYDD's aims were to:

  • celebrate deserts' unique biological and cultural diversity, while raising awareness of the need to protect these unique resources; and
  • highlight the growing threat of desertification to humans, especially in light of desertification's implications for achievement of the Millennium Development Goals (UN 2005).

It is the first of these themes that this issue of the Arid Lands Newsletter addresses.

In June 2006, UNESCO organized an international scientific conference, "The Future of Drylands," in Tunis. Conference participants adopted a "Declaration on Research Priorities to Promote Sustainable Development in Drylands," which "calls upon governments to use sound scientific knowledge to formulate and implement policies, laws, regulations and action programmes vis-à-vis environmental issues" (UNESCO 2006, 2).

But making good decisions and implementing them is not just a matter of resolve. As astronomer and Nobel Prize winner Arno Penzias once wrote, "'Deciding' means acting on information. Barring blind luck, the quality of a decision can't be better than the quality of the information behind it." (Penzias 1989, 22).

This basic principle guides this issue's articles and their approach to the topic of "what's special about drylands." Ultimately, if we are to devise strategies to cope with problems such as desertification, their success depends substantially on the quality of our scientific understanding of how drylands work, and on the comprehensiveness of the data that support this understanding. Without good data, it's exponentially more difficult to distinguish between natural variations and profound changes in ecosystem behavior—as well as to develop appropriate management strategies for coping with either.

The first article provides a historical perspective. In 1955, UNESCO and the American Association for the Advancement of Science sponsored the "International Meetings on Drylands" in New Mexico, USA. Their purpose was to summarize the current scientific knowledge about drylands and propose an agenda for addressing gaps in that knowledge, in order to make "the best use of drylands." In 1956, "The future of drylands" was published, comprising papers and recommendations from the New Mexico meetings (White 1956). As part of IYDD activities in 2006, UNESCO commissioned a team of scientists from the Office of Arid Lands Studies, The University of Arizona, to write a new book that reviews the 1956 work, assessing where we are now relative to then in terms of our knowledge of the science of drylands.

Because the themes of this new work are so pertinent to the current issue of ALN, this first article, written by ALN editor Katherine Waser, provides a brief summary of the upcoming book's main points. It turns out that our scientific understanding of drylands has changed in many ways in the past 50 years. We now have a much better understanding of the complexity of global systems and their interactions. We now have computers and other technological tools that can handle the massive quantities of data needed to analyze and characterize these complex systems. We now recognize that realistic solutions to ecological problems can't be developed without considering, and providing for, the humans and human livelihood systems that depend on these ecosystems. The hope of the book's authors is that this scientific understanding will ultimately translate into better development policies and land management strategies for drylands in the future.

The second article tackles one of the seeming paradoxes of deserts: despite their highly variable climates and their scarcity of water, they often harbor astonishing biodiversity. How can this be? Authors Mary Price and Nick Waser, both ecologists, state the question in ecological terms: what mechanisms allow all of these species to coexist, when they all rely on the same scarce resource—water? The answer, they propose, lies in two factors: the variability (spatial, temporal, and in duration) of rainfall events in deserts and the inability of any one organism to effectively exploit all sizes of these rainfall events. In effect, variability of climate in this case creates a multitude of ecological niches; since no one species can exploit all these niches, this permits the development of high levels of biodiversity despite the scarcity of water.

Not only that, the authors posit that "the particular mix of organismal strategies will vary among deserts that have different patterns of water input", supporting this position with examples from their own fieldwork in the Sonoran Desert of North America and the Simpson Desert of Australia. This is a valuable reminder that, as important as statistical averages are for scientific understanding of global drylands and climate patterns in general, when the topic is individual desert ecosystems, tracking local patterns is also crucial. As the global climate warms, all denizens of drylands—human or otherwise—will have to cope with increasing unpredictability. The better our current understanding "about deserts, their differences around the planet, and the strategies of plants, animals and humans that have adapted to them and to their inherent variability", the more likely it is that we will be able to develop effective strategies for coping with changing desert climates and increasing drylands desertification in the future.

To be able to track climate change and its effects, we must not only develop the best information we can about what current, "normal" conditions are; we will also have to measure changes in these conditions when they occur. As climate scientist Mark Losleben and geographer Wim van Leeuwen point out in the third article, an excellent tool already exists for tracking such changes. This tool is phenology: "periodic plant and animal life cycle events that are influenced by environmental changes, especially seasonal climate-driven variations in temperature and precipitation."

Although the term "phenology" is unfamiliar to many people, phenological events such as the timing of bird migrations or of flowering of fruit trees and other crops have been observed by human beings for millenia. In recent decades, scientists have recognized that changes in the timing of phenological events can provide direct evidence of climate change—as, for example, in the well-documented case of earlier onset of growing seasons in many regions of the globe. Furthermore, because phenological events are readily apparent to the public at large, phenology is an ideal tool for raising public awareness about climate change and its local effects.

Tracking climate change through phenological observations, though, will require massive amounts of data collected over large spatial areas through both remote sensing and direct on-the-ground observations. The data will furthermore have to be efficiently collated, analyzed and then disseminated to the land managers and policy makers who most directly need this information. This task is beginning to be addressed through the establishment of phenology monitoring networks that leverage already existing capabilities to carry out the work. The authors focus on the newly established USA National Phenology Network as an example of how such networks can be set up. While phenological monitoring is a tool that can be used in most types of ecosystem, it promises to be particularly useful in drylands where climate variability is naturally high, ecosystems are especially vulnerable to change, and being able to distinguish real change from natural variation is thus especially crucial.

A particularly interesting aspect of the USA-NPN is its intent to make heavy use of "citizen-scientists" to provide local-level phenological data. Citizen-scientists might be students, teachers, gardeners, hikers, backyard naturalists—in short, anyone who's interested in local phenological events and keeping track of them. Top-down technology isn't sufficient for the data-gathering efforts that will be needed to make the USA-NPN a success; it will take bottom-up, on-the-ground participation too, a partnership of technology and people. Thus, just as current development planning recognizes the importance of local knowledge and commitment to any development project's success, the notion of "citizen scientists" acknowledges the importance of locally gathered data to the success of efforts to model global systems and develop strategies to mitigate environmental problems.

Whether expressed in a pastoralist's ability to judge precisely the best moment to move his flocks or an urban gardener's decades-long record of when her fruit trees flower, local knowledge, as well as scientific expertise, will be an essential element of any successful mitigation strategies devised to combat desertification. And this gets us back to a theme often stressed in these editorial pages: Solving these problems and protecting the unique nature of drylands will take everyone's best efforts. We can all observe; we can all act; we all have something to contribute. We are in fact all "citizen scientists" of planet Earth, and the individual actions we each take, however small they may seem, can indeed be of vital importance to our common future.


Penzias, Arno. 1989. Ideas and information: Managing in a high-tech world. New York: Norton.

UNESCO. 2006. International Scientific Conference "The Future of Drylands", Tunis (Tunisia), 19 to 21 June 2006: Declaration on research priorities to promote sustainable development in drylands, or the "Tunis Declaration". Online:

United Nations. 2005. Millennium Development Goals web site. Online:

White, Gilbert (ed). 1956. The future of arid lands: Papers and recommendations from the International Arid Lands Meetings. Washington, D.C.: American Association for the Advancement of Science.

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