|Heilman, Philip - Phil|
Submitted to: Biodiversity & Management of the Madrean Archipelago Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2005
Publication Date: 9/1/2005
Citation: Buono, J., Heilman, P., Williams, D., Guertin, D.P. 2005. Assessing indicators of rangeland health with remote sensing in southeast arizona. Proc. Biodiversity and Management of the Madrean Archipelago II Conf., Connecting Mountain Islands and Desert Seas, May 11-14, Tucson, AZ, pp. 508-510. Interpretive Summary: There are approximately 5.6 million acres of semi-desert grassland in Southeast Arizona. Land management in this area relies on a diverse mix of state and federal agencies as well as private land owners and non-governmental organizations. Rangeland management programs have traditionally relied on data acquired at plot and pasture scales. However, field data collection is time and labor intensive; land managers are increasingly requiring less expensive and timelier information. The goal of this study was to devise and evaluate a cost-effective method of scaling up range assessments from ground based, pasture-scale assessments to ranch and landscape scales using satellite derived measurements. By combining these measurements with information collected on the ground, a method was developed to assess at the landscapes scale. This new method uses established field-based protocol but replaces ground measurements with information derived from a satellite. Accomplishments of this study include the development of evaluation criteria for two types of rangeland ecological sites and an assessment of these sites covering 1386 km2 in Southeast Arizona. The study also identified several of the major constraints involved in scaling-up assessments which will direct future research. These include the difficulty of developing ecological maps for large areas, errors associated with using satellite measurements of rangeland indicators, and the confounding effects of rainfall variability. Ultimately, this study will contribute to our understanding of landscape ecology assessment and monitoring potentially allowing for more effective management of public lands.
Technical Abstract: The goal of this study was to scale up ground based range assessments to ranch and landscape scales in Southeast Arizona using remote sensing and minimum amount of field data collection. Remotely sensed metrics of canopy cover, biomass, and mesquite composition were used to assess soil and site stability and biotic integrity. Ground-based assessments were conducted on eleven field locations and used in conjunction with Natural Resources Conservation Service (NRCS) ecological site descriptions to develop evaluation criteria on two different ecological sites. The data were combined in a GIS and 1386 km2 of rangelands were assessed. A total of 13% of loamy upland range sites were categorized as 'None to Slight Departure' from reference conditions for soil and site stability and 63% were categorized as 'Moderate to Extreme Departure' for biotic integrity. The model was sensitive to variation in climate and management. This method is currently being developed as a potential tool for land managers in Madrean Archipelago.