Submitted to: Journal of Arid Environments
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/7/2005
Publication Date: 4/1/2006
Citation: Estell, R.E., Fredrickson, E.L., Peters, D.P.C. 2006. Introduction to special issue - Landscape linkages and cross-scale interactions in arid and semi-arid ecosystems. Journal of Arid Environments. 65:193-195. Interpretive Summary: Loss of grasslands due to shrub invasion into arid and semiarid rangelands (known as desertification) is a serious problem. The processes that cause these transitions are not completely understood. 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. Scientists at the Jornada Experimental Range (JER) are addressing these problems using a collaborative, multi-disciplinary approach. Scientists affiliated with the Jornada Basin Long-Term Ecological Research site in collaboration with scientists from the JER and New Mexico State University have generated a number of new ideas and concepts about desertification. Vegetation patterns are highly variable in terms of both time and space in these environments. Because this variation cannot be explained or predicted well with our current knowledge, JER scientists have developed models that consider nonlinear dynamics and connections among land units of different sizes. Factors such as historical legacy (past land uses and events) can have profound influences on current vegetation patterns (e.g., mesquite invasion), as can soil characteristics and topography, soil fungi, wind erosion, and timing of precipitation cycles. Natural and manmade features of the landscape can be used to take advantage of concentrated water during precipitation events. Science-based land management that incorporates existing knowledge with new information to monitor and assess arid and semiarid ecosystems is also being developed.
Technical Abstract: The conversion of grasslands to shrublands in arid and semiarid 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. Since 1981, scientists affiliated with the Jornada Basin Long-Term Ecological Research site 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. The realization that our current knowledge often cannot explain the existing variability among land units led to the development of a conceptual model by JER scientists that considers nonlinear dynamics and connections among land units across scales. This cross-scale landscape ecology approach will further our understanding of critical processes occurring in arid regions globally and will provide insight to help identify mechanisms to address the pressing issue of desertification.