Evaluation of multispatial scale measurements for monitoring wetland vegetation, Kushiro wetland, Japan: application of SPOT images, CASI data, airborne CNIR video images and balloon aerial photography

Abstract

Our study was designed to evaluate the potential use for various spectral and spatial resolutions to classify the wetland vegetation into the species level. The objectives of our study is to investigate which combination of remote sensing systems is the most appropriate for delineating and mapping of specific and preservative vegetation. That is, to clarify appropriate remote sensing data and platforms for detecting and mapping of high-resolution of multispartial scale measurements for classification of wetland vegetation and to elucidate spatial character for classification of specific and typical patterns and community types. The site specification, Kushiro wetland, northeastern Japan, is designated as a Ramsar wetland of international importance. Plant ecologists have emphasized the importance of preservation of the vegetation characterized by high biodiversity and high spatial heterogeneity. The elaborate vegetation mapping to monitor the distribution has been imperative. The mission we employed had four main stages, 1) Spectra of each representative wetland vegetation canopy were collected in situ by a field portable multi-spectral radiometer (operating at 380-900 nm). 2) Photo-interpretation of mosaicking balloon aerial photos with high resolution (15cm/pixel) and classification of wetland vegetation including extensive ground truth, in the summer of 1998 and 2001, and the spatial analysis of patches in landscape level. 3) Using high spatial airborne Color Near Infrared (CNIR) sequence video images at a resolution of 30 cm/pixel with 3 bands, including off-nadir observation and airborne CASI data, 4) Utilization of SPOT-2 (HRV) images and evaluation for mapping . Those images obtained in summer were classified to produce an accurate base map of wetland vegetation as reference data. Each classified image was assessed using a combination of field mapping techniques and patch analysis. We got twenty-seven categories of individual vegetation and ten typical types of vegetation community with higher classification accuracy. In addition, the extract conservative wetland communities, twenty-two genera and thirty-nine species were mapped. It was apparently suitable for delineating and mapping the specific temperate vegetation types at genus and species levels, especially small shrubs mixed with herbaceous plants, moss bog with pools and dwarf shrubs with sedge, moss and alpine plants with environmental conditions of vitality and phenology in Carex. spp. and Phragmites australis. This paper provides the capabilities for monitoring the typical type of temperature wetland vegetation.