Center for Spatial Technologies and Remote Sensing (CSTARS)
Ecology Graduate Group
University of California
Davis, CA, 95616, USA
rjzomer@ucdavis.edu
SUMMARY
A methodology for rapid ecological assessment analysis in remote and mountainous parks was applied to the problem of resource and data limitations faced by park managers and conservationists. Application of a combined fieldwork and satellite remote sensing approach formed the basis for a land use /land cover change analysis of low elevation riparian corridors within the Makalu Barun National Park and Conservation Area of east Nepal. Although issues of scale, resolution, and accuracy remain to be solved, it has clearly been demonstrated that application of a suite of advanced remote sensing and spatial analysis tools can provide new environmental data sources and timely access to a cost-effective analytical capability, even within the most extreme remote and mountainous terrain.
Analysis of forest and vegetation data using advanced multivariate statistical techniques was able to discern several significant relationships between forest community structure, species composition, and spatial distribution of communities across physiographic and anthropogenic resource use gradients. Although resolution of the satellite imagery used was not able to distinguish between forest community types, the supervised classification of the Landsat TM data did successfully discern the major forest formations. Combining information hierarchically across landscape units, that is from the forest community analysis to the landscape classification, enhanced overall information content and utility to managers. Further, information about the spatial distribution of forest communities across physiographic gradients provided significant ancillary data which enhanced selection of training sites and landuse classes used in the supervised classification of the remote sensing data. Subsequent to the production of the landscape level forest and landuse classification, detailed community analysis data provided the information content for assessing ecological status and condition of the various landscape units.
The production of intermediate map products early within a research project cycle greatly improves the efficiency of field research and mapping. Likewise, providing a common geospatial reference framework early in the project cycle can contribute significant efficiency improvement, especially in facilitating the exchange of georeferenced spatial databases among fieldworkers, researchers and institutions. A particularly valuable component of our research was application of stereo photogrammetric techniques to the production of a digital elevation model (DEM) from remote sensing sources. The extracted DEM, although somewhat less accurate than results obtained from similar scale conventional datasets, did provide a basis for highly accurate orthorectification of various remote sensing datasets. Orthorectification provided the critical component necessary for comparison among the diverse remote sensing datasets, and the integration of global positioning system georeferenced field data. Production of orthorectified map products for field use allows for easy location and identification of field sites. The production of a satellite base map combining spectral discrimination with enhanced spatial resolution enables estimation of extent and distribution of similar landuse and forest type categories in the field.
As a practical demonstration of the utility of these methodologies, the data acquired were applied to the investigation of landuse and cover change along tropical riparian corridors. Change detection analysis revealed significant impact in the twenty years immediately proceeding the establishment of the MBNPCA. Although little significant change was evident in overall extent of tropical and subtropical riparian forests, a net loss of 11% was estimated for all forest types across all landuse categories. Significant internal trading between landuse classes clearly demonstrates the highly dynamic nature of landuse within the mountain farming system. Further, results highlight the important role of riparian corridors and remnant tropical /subtropical forests for biodiversity conservation in the Middle Hills of east Nepal.