ASSESSING CLIMATE CHANGE IMPACTS TO LANDSCAPES AND ECOSYSTEMS: A NAVAJO EXAMPLE FROM THE SOUTHWESTERN US

Assessment of how climate change has altered ecosystems can be challenging due to the resulting variations in hydrologic and geomorphologic processes, and linkages of these systems to local biomes. Climate-sensitive ecosystems undergoing the most dramatic changes include desert margins, mountainous regions or islands, as well as polar regions that may have been poorly monitored or studied occasionally if at all. These landscapes are often the vestiges of land occupied by Indigenous peoples. We present an assessment of change in one such area, an ecologically sensitive semi-arid region of the Navajo Nation, roughly comparable in size to Iceland. One aspect of this work is to study and document the biophysical processes that link landscape change and climate. Additional work emphasized here examines the relation between these conventional data, and changes in land use, living conditions, and traditional Indigenous cultural practices.

The lifetime observations of 105 Navajo elders provide an additional record of ecosystem change. Consultants included ceremonialists (medicine men), traditional botanist healers, and those considered knowledgeable about local history and place names. Among the most cited changes was a long-term decrease in snowfall over the past century, and a long-term trend to more arid conditions, first noticeable in the 1940s. Other noted changes include decreasing surface water sources and springs, the availability and distribution of medicinal plants, and the disappearance of cottonwood trees, beavers, and eagles. The lack of available water was mentioned as a leading cause for the decline in the ability to grow corn and other crops. Changes in the frequency of wind, sand and dust storms (more frequent in the 1950s and increasing in the 1990s) were also observed. This local knowledge that is based on subsistence practices refines our assessment of climate-induced landscape changes and resulting human system vulnerability to climate extremes.