Introduction to special issue—Landscape linkages and cross-scale interactions in arid and semi-arid ecosystems

摘要

The conversion of grasslands to shrublands in arid and semi-arid ecosystems is a serious global problem. Although a great deal of research has been conducted on these conversions, we lack a complete understanding of the processes underlying the transitions. More importantly, our ability to predict when and where desertification will occur and our ability to manage landscapes to prevent degradation and restore degraded landscapes is limited. Research being conducted at the Jornada Experimental Range (JER) is addressing these problems in a new, synthetic way. The JER, established in 1912, is a USDA Agricultural Research Service field station located in the northern Chihuahuan Desert (southern New Mexico, USA; 32°37′N, 106°44′W). The original mission of this federal research facility was to improve forage and livestock production on arid and semi-arid rangelands. As the science of rangeland management evolved and the scope of study expanded (e.g., hydrology, ecology, wildlife, etc.), the research mission of the JER evolved as well; however, livestock management has continued to be a central theme of the research program. Since 1981, scientists affiliated with the Jornada Basin Long-Term Ecological Research site (funded by the National Science Foundation) in collaboration with scientists from the JER and New Mexico State University generated a number of new ideas and concepts regarding the processes governing desertification that changed our thinking about how these systems operate. Our focus now emphasizes cross-scale spatial and temporal heterogeneity in vegetation patterns and dynamics that have been difficult to explain using traditional approaches (Peters and Havstad, 2006; and references within).