Watershed Characterization Approach to Redefine Bioregions: A Case Study at Moro and Iagifu Bioregions in Southern Highlands Province, Papua New Guinea

Abstract

A watershed is the natural laboratory of water, soil, flora, and fauna. It is the land area where all precipitation drains to a lake, sea, or river through a common outlet. Demarcation of the watershed is generally performed using the Digital Elevation Model through topographic analysis. However, this method doesn’t consider environmental processes and ecological relationships. This study employed the watershed characterization technique to define ecoregions and subsequently merge them to delineate a bioregion, utilizing geographical information science and systems (GIS) and remote sensing. It incorporated empirical and statistical data from six significant environmental variables: physio-geography, soil, climate, natural communities (focusing on flora), ecological processes, and hydrology. There is insufficient recognition for the watershed approach used in environmental impact assessments or analyses in Papua New Guinea. The study has shown that this technique can be highly effective, particularly in supporting watershed management practices, environmental planning, and natural resource management. To utilize this technique, one must understand the ‘system of relationships’ among the six significant ecological variables and how they interrelate and correlate within this dynamic bioregion. This research delineates more precise boundaries of the defined bioregions based on the scientific approach compared to the existing bioregions.