Biodiversity / Plants

The lichens in GHNP are more than 10% and 50% of the lichens recorded from India and central Himalaya respectively. Tirthan and Jiwa valleys have relatively higher diversity of lichens represented by 101 (53%) and 100 (52%) species respectively, while the diversity of lichens in Sainj valley comprises of 67 species (35%). Saxicolous species (rock inhabiting) has higher diversity (40 species) in both Tirthan and Sainj valleys, which can probably be attributed to their large alpine meadows with exposed rocks. Interestingly, 78% (149) of the species were representatives of the corticolous category while the other groups such as saxicolous, terricolous, and folicolous were represented by only 54, 29, and 3 species respectively. The elevation ranges between 2,500 and 3,000 m harbours the maximum diversity of lichens. This can probably be attributed to a lower degree of pollution and higher tree density in these areas. Kharsu oak forests appear to be supporting rich lichen diversity, particularly Phorophytes, in Sainj and Tirthan valleys (49 species each) as compared to Jiwa valley (30 species). Distinctly, a few species are found growing on specific host trees and this has direct management implications. At lower altitude, the smooth bark of the tree species of llex and Quercus leucotrichophora support lichen species of Pyrenula and Anthracotheclum. Nephroma helviticum is found to be growing exclusively on the barks of Prunus cornuta. Growth of Sulcarla sulcata is restricted to conifer trees. Ochrolechia rosella, Menegazzla terebrata and Hypogymnia vittata grow abundantly only on Quercus semecarpifolia. Interestingly, these lichen species seem to follow a distinct vertical distribution pattern associated with the tree species that represent different climatic zones.