Impact of nomadic grazing on medicinal plants diversity in Miandam, Swat-Pakistan (Preliminary results)

摘要

The coniferous forest play vital role to support the livelihood of rural poor and?provides goodecological services for the maintenance of ecosystem. In this context the present study was initiated with the aim to evaluate the impact of nomadic grazing on the plant diversity, with special focus on medicinal flora. Comparisons were made between two sites; one protected from grazing for about seven years, the other being exposed to continuous nomadic grazing. Results of the survey showed that nomadic grazing poses serious threat to the occurrence and the distribution of medicinal flora. The area protected from nomadic grazing showed better vegetation cover and medicinal plant diversity. In August 2007, 33 medicinal plant species were found in the unprotected site, while 78 species were recorded in the protected site. It was also found that the medicinal plants diversity had decreased in the former site by about 90%. Moreover, two species?Paeonia emodi?andPodophyllum emodi?had completely disappeared from the nomadically-grazed area. It was also observed that overgrazing had negative impact on the natural regeneration of conifers: 66 saplings were counted per ha in the grazed area compared to 840 saplings observed in the protected area. The study also observed that the availability of economically and therapeutically important plant species is decreasing and the number of rare and threatened species among the medicinal plants is increasing in the area. Further study is, therefore, required to quantify the availability of species and to suggest suitable method for their production and conservation.