Population density, life history traits and traditional ecological knowledge of Paris polyphylla Sm. in Dolakha, Nepal

Abstract

A number of medicinal and aromatic plants (MAPs) are threatened because of increasing cross border trade, habitat destruction and unsustainable harvesting. The life of people who depend on these resources and the knowledge associated with them are also under the threat. Paris polyphylla Sm. is one of those plants which has seen rapid rise in its global demand and concerns are being expressed about its declining wild populations. However, like many other medicinal plants, the data on population parameters and performance across the distribution range are largely lacking. Despite different studies identifying the need for recognition of the distribution pattern and biological traits of medicinal plants to assist conservation efforts, there has been very little empirical data and more focus has always been placed on the possibility of discovering novel wonder drugs. Therefore, in the present study, the population density and structure and variability in the performance of P. polyphylla between three different populations (lower temperate, mid temperate and upper temperate) across an elevation range (1800-3100 m asl) in Dolakha, Nepal has been assessed. The results showed that in all the population, the density of juveniles was lower than that of vegetative and reproductive adults. The mean density varied between 0.55 ± 0.05 and 1.4 ± 0.13 individuals/m 2 with the mid temperate population having the highest average density and the lower temperate having the least. Among different environmental variables, human disturbances (trampling and harvesting) and topographic parameters were the major factors contributing to variability in density and performance of the plant. The majority of the features were lowest in the upper temperate zone (at the highest elevation). The persistence and growth of P. polyphylla will depend on the effectiveness of measures adopted to control over-harvesting and premature harvesting of rhizome and also protection of younger life stages. In addition, P. polyphylla populations must be protected from other typical anthropogenic disturbances such as grazing and trampling.