Image Utilisation for the Study and Management of Riparian Vegetation: Overview and Applications - Fluvial Remote Sensing for Science and Management - page 209

10

Image Utilisation for the Study
and Management of Riparian
Vegetation: Overview and
Applications

Simon Dufour 1 , Etienne Muller 2 , Menno Straatsma 3
and S. Corgne 1
1 LETG - Rennes COSTEL, CNRS, Universite Rennes 2, Place Recteur
Henri le Moal, France
2 Universite de Toulouse; CNRS, INP, UPS; EcoLab (Laboratoire Ecologie
Fonctionnelle et Environnement), France
3 University of Twente, Enschede, The Netherlands

resulted in an increased activity in managing riparian veg-
etation and led to scientific studies into the understanding
of riparian systems. Thus, both managers and scientists
need a set of tools that are able to sense, describe and
monitor vegetation quality but that are also efficient in
riparian corridors. High spatial complexity and temporal
fluctuations complicate the transferability of these tools.
The main dichotomy in these tools is between image
analysis and field survey.
Over the last few decades, image analysis has under-
gone a huge evolution due to an increase in sources and
the type of imagery (Figure 10.1). For example, very high
resolution satellite images, such as IKONOS or GeoEye,
combine high spatial resolution with a broad areal cov-
erage. The emergence of new technologies gives access
to new information such as forest stand structure. More-
over, image analysis has greatly progressed, resulting in an
increase in computing capacity, geographic information
system (GIS) techniques and advanced image analysis

10.1 Introduction

Riparian vegetation is an important component of fluvial
landscapes. The extent of vegetated areas within riparian
systems, defined by Naiman et al., 2005, as 'transitional
semi-terrestrial areas regularly influenced by freshwater,
usually extending from the edges of water bodies to the
edges of upland communities', is variable in space and
time. It fluctuates under the control of internal pro-
cesses such as biological interactions, but also due to land
cover changes. Riparian vegetation affects morphological
changes of the channel, flood hazard and ecological func-
tioning (Gurnell and Gregory, 1995; Tabacchi et al., 1998;
Tal et al., 2004; Corenblit et al., 2007). It is also a nat-
ural and cultural resource that provides services such as
biodiversity, refuge for endangered species, recreational
areas and pollution limitation (Malanson, 1993; Klimo,
2008). The recognition of the interest in such ecosystems