RESIDUAL VALUE ANALYSES OF THE MEDICINAL FLORA OF THE WESTERN HIMALAYAS: THE NARAN VALLEY, PAKISTAN

Statistical analyses of the medicinal flora of the Naran Valley in the Western Himalayas were performed using Moerman's methods and Principal Components Analysis (PCA). The results demonstrate that the valley's indigenous people utilize medicinal plants in a systematic way. Sixty-eight families of plants were identified during the study, of which 52 contained one or more species of medicinal value. The standard deviation for residual values of all the 68 families was 0.993 and the results of the residual analysis revealed that seven of these plant families were overused by the local people, indicated by residual values greater than the standard deviation. Residual values obtained from a regression analysis of plant species with their medicinal uses showed that the families with the highest rank were Polygonaceae, Gentianaceae, Lamiaceae, Rosaceae and Plantaginaceae, indicating their medicinal importance. By comparison, Poaceae, Boraginaceae, Primulaceae, Salicaceae, and Ranunculaceae were the lowest ranking families, containing few species of medicinal value. Although a few of the most species-rich families in the valley contained a high number of medicinal plants and hence displayed high residual values, some other species-rich families contained few or no species of medicinal value. For example, the third largest family, Poaceae, is the lowest in terms of its residual value, while the largest family, Asteraceae, contains only seven species noted as having medicinal uses. Sixteen plant families in the valley contained no species with reported medicinal use, while seven families contained only one species with medicinal value. In contrast, all of the species in several of the least species-rich families were recorded as having a medicinal use. The results of a Principal Components Analysis showed a gradient of medicinal plant use along the valley. Using robust statistical approaches, our study provides a clear indication that the indigenous people of this Western Himalayan valley utilize wild plants according to their traditional knowledge and not on the basis of plant abundance.