Highlands, Midlands, Lowlands: Spatial Explicit Models to Study Vertically Differentiated Areas

Several variables important to life processes vary predictably with altitude, resulting in the distinct environmental gradients found in mountainsides. Mountains are intricate socio-ecological systems that integrate physicochemical, sociocultural, and biological phenomena. Therefore, defining, conceptualizing, categorizing, and mapping mountains require appropriation of altitudinal zonal characteristics as pathways toward sustainable and regenerative mountain development. The categorization of vertically differentiated areas into Highlands, Midlands, and Lowlands is as complex as their definition. Various factors like local relief, slope steepness, and quantity of land in the slope are incorporated for defining "Mountains" discussed in this chapter. The work will explain the recent altitudinal classification schemes and how it results in a different configuration of vertically differentiated areas across several latitudes. A classification scheme based on the narrative of altitudinal geoecological approaches has been proposed to combine different environmental factors along a single vertical gradient given by Mountain Research Institute (MRI) to define the Highland, Midland, and Lowland area. The whole discussion provides an overview of different geoecological parameters generally used to classify mountain areas while exploring a few exceptions and limitations.