An assessment of the degree to which Landsat TM data can support the assessment of fluvial dynamics, as revealed by changes in vegetation extent and channel position, along a large river.

Recent research has demonstrated the capacity of remotely sensed data to enhance our understanding of interactions between fluvial processes and riparian vegetation. Multispectral Landsat TM satellite data covering the last 30 years are now freely available and have the potential to support investigations at much broader spatial and temporal scales than previously possible. This paper assesses the degree to which this data set can support the assessment of fluvial dynamics along a large gravel bed river, the Fiume Tagliamento, NE Italy. Landsat TM scenes are used to determine spatio-temporal trends in vegetation cover and channel position at six sites of contrasting environmental conditions along the river. These trends are interpreted in combination with a number of additional hydrogeomorphological data sets before comparison with known biogeomorphological characteristics of the study sites as revealed by previous field research and analyses of higher resolution remotely sensed data sets. The research highlights a number of limitations with Landsat TM data that arise as a result of its relatively low spatial resolution including geomorphic feature definition and active tract delineation. Nevertheless, the analysis demonstrates that Landsat TM data can reveal a wealth of information that could support further biogeomorphological investigations in other large rivers.