Demonstration of a satellite-based index to monitor habitat at continental-scales

An important initial step in the conservation and sustainable management of the Earth's biodiversity is to implement systems to both identify and subsequently monitor components of biological diversity, along with developing a better understanding of the processes that significantly threaten their conservation or sustainable use. Key factors in both species diversity and richness are related to environmental heterogeneity which is driven by temporal and spatial variation in the biological, physical, and chemical features of the environment. These environmental characteristics are manifest through the condition and change in vegetation productivity (considered as an integrated response of vegetation to climate and soil conditions). Earth observation is uniquely capable of synoptically covering large areas of the planet in a repeatable, and cost effective manner, and is a well-established technology for detecting terrestrial vegetation productivity. A recently developed dynamic habitat index (DHI), based on satellite observations of the fraction of radiation absorbed by the canopy (fPAR), has been shown to effectively cluster remotely sensed observations into a range of habitat regimes which in turn have been related to breeding bird surveys in the Canadian Province of Ontario and across the conterminous United States. With evidence that the index is well correlated with species diversity, we consider, in this subsequent paper, whether such an index is a suitable candidate as a continental index to characterize and subsequently monitor habitat conditions, To do so, we first utilise available fPAR data available from 2000 to 2005 over North America, and apply the index. Using information on continental terrestrial ecozones and their ecological distinctiveness, we then compare and contrast the index and utilize trajectory analysis to assess what changes have occurred in the index over the 6-year time period and possible implications for continental biodiversity. The potential application of the index is the discussed. (C) 2008 Elsevier Ltd. All rights reserved.