Review Article Digital change detection methods in ecosystem monitoring: a review P. COPPIN*, I. JONCKHEERE, K. NACKAERTS, B. MUYS Geomatics and Forest Engineering Group, Department of Land Management, Katholieke Universiteit Leuven, Vital Decosterstraat 102, B-3000 Leuven, Belgium and E. LAMBIN Department of Geography, Universite ´ Catholique de Louvain, 3 Place Pasteur, B-1348 Louvain-la-Neuve, Belgium Abstract. Techniques based on multi-temporal, multi-spectral, satellite-sensor- acquired data have demonstrated potential as a means to detect, identify, map and monitor ecosystem changes, irrespective of their causal agents. This review paper, which summarizes the methods and the results of digital change detection in the optical/infrared domain, has as its primary objective a synthesis of the state of the art today. It approaches digital change detection from three angles. First, the different perspectives from which the variability in ecosystems and the change events have been dealt with are summarized. Change detection between pairs of images (bi-temporal) as well as between time profiles of imagery derived indicators (temporal trajectories), and, where relevant, the appropriate choices for digital imagery acquisition timing and change interval length definition, are discussed. Second, pre-processing routines either to establish a more direct linkage between remote sensing data and biophysical phenomena, or to temporally mosaic imagery and extract time profiles, are reviewed. Third, the actual change detection methods themselves are categorized in an analytical framework and critically evaluated. Ultimately, the paper highlights how some of these methodological aspects are being fine-tuned as this review is being written, and we summarize the new developments that can be expected in the near future. The review highlights the high complementarity between different change detection methods. 1. Introduction Ecosystems are in a state of permanent flux at a variety of spatial and temporal scales all around the world. Causes of these fluxes can be natural as well as anthropogenic, or may be a combination of the two. Moreover, scientific evidence clearly points to the fact that impacts of, for example, global change on land surface attributes are not uniformly distributed on the face of the Earth. The fact that sustainability has become a primary objective in present-day ecosystem management has as one of its consequences the continuous need for accurate and International Journal of Remote Sensing ISSN 0143-1161 print/ISSN 1366-5901 online # 2004 Taylor & Francis Ltd http://www.tandf.co.uk/journals DOI: 10.1080/0143116031000101675 *Corresponding author; e-mail: pol.coppin@agr.kuleuven.ac.be INT. J. REMOTE SENSING, 10 MAY, 2004, VOL. 25, NO. 9, 1565–1596