The US Environmental Protection Agency (EPA) awarded on a highly competitive basis an innovative research grant for 1991-94 for a proposal developed by EHC and submitted on behalf of a USEPA Lab (Las Vegas) on ‘methods for evaluating the recovery of stressed or perturbed ecosystems as a measure of ecosystem health’. This study, conducted in collaboration with the Desert Research Institute made use of existing satellite data coupled with field activity to provide ground-based data verification, on several key parameters, including primary productivity, ground cover, species composition, and the ratios of native/exotic species.
The work was carried out using the facilities of the Jornada Long-Term Ecological Research Station at Las Cruces New Mexico, with the assistance of senior scientists from the Desert Research Institute. Monitoring vegetation for specific indicators of arid ecosystem health, before, during and after a major drought enabled the research team to piece together the complex picture of arid ecosystem response to stress from overgrazing and drought. Extensive use was made of the applications of the NDVI (normalized difference vegetation index) as a reliable estimator of biomass and primary productivity. The results of the research were reported in several peer-reviewed scientific publications.
Whitford, W, Rapport, D.J. and deSoyza, A., 1999. Using resistance and resilience measurement for “fitness” tests in ecosystem health. Journal of Environmental Management 57, 21-29
Rapport, D.J. and Whitford, W. 1999. How ecosystems respond to stress: Common properties of arid and aquatic systems. BioScience 49(3): 193-203.