Lichens

(1) The diversity of lichens in china

Lichens are a group of specialized fungi which are associated with algae and/or cyanobacteria, and form mutualistic ecosystems. About 20, 000 lichen species are known in the world. of these, no more than 2, 000 are known from China, including 200 endemic species. However the total number of lichen species, both in the world and in China is probably greater. The study of lichen species diversity in China is just beginning.

(2) Rare and endangered lichens in China and the threats to them

Air pollution and the destruction of the forests are serious threats to the diversity of lichens in China. Some epiphytic lichens which live on the bark of forest trees, such as Hypogymnia hypotrypa, H. hytotrypella, H. pruinosa, H. laccata, H. hengduanensis, and Umbilicaria yunnanu, are endemic to China or East Asia and are presently facing extinction. Their survival is closely linked to that of the forest ecosystem. China’s epiphytic lichen, Lasallia mayebarae, with a distribution restricted to the pine forests of Lijiang, Yunnan Province. and Ali Shan Mountain, Taiwan, has an important evolutionary significance. In Lijiang, this world rare lichen species has disappeared due to forest fires. Along with the rapid development of tourism, the existence of the rare epilithic lichen Rhizoplaca huashanensis, endemic to Mt. Huashan, is also faced with extinction. In addition, the famous east-Asian edible lichen, Umbilicaria esculenta, which also has the potential to produce anti-tumour and anti-aids virus substances, is disappearing in Lushan, owing to uncontrolled collecting and selling. The widely distributed lichens Evernia mesomorpha and Ramalina fasitgiata, have important significance for the spice industry and Cladonia delavayi, has relevance to the treatment of prostatitis. The lichens Thamnolia vermiculaaris and T. subuliformis used to treat hypertension, will not escape the same misfortune in China unless we take the necessary measures to protect them.

(3) Protect lichens

It has been a long process for Man to recognize the value of lichens, so that the exploitation and utilization of them are still unrecognized even though it is a treasure-house of biological resources with great potential. The challenge for today’s pharmaceutical industry lies in the discovery and development of new, pharmacologically active, substances. Metabolites produced by lichens are a resource and have been long neglected by biologists, and overlooked by industry. For today's pharmaceutical industry, therefore, lichens are virgin soil which remains to be exploited. Lichens are, however, extremely slow-growing and long-lived. Many lichens are in danger of becoming extinct due to air pollution and the destruction of forest ecosystems. Strengthening lichen diversity protection is an urgent task.

In order to protect lichen diversity, except by preserving forest ecosystems upon which they depend, the following measures should be paid attention to:

a. Lichen resources used for daily spices, medicinal materials and foodstuffs, should be collected in rotation in different areas each year.

b. For rare species with important scientific significance, such as Rhizoplaca huashanensis in Huashan, Shaanxi Province, Lasallia mayebarae in Lijiang, Yunan Province and Umbilicaria esculenta in Lushan, Jiangxi Province and which are endemic to China, we should select suitable locations to establish small protected areas for them.

c. At the same time, for some of the more important lichen species mentioned above, we should adopt measures to culture separately the mycobionts and photobionts, and establish gene banks for them. Serial measures for the multi-level protection of species is an important direction for lichen conservation and sustainable utilization.

d. Strengthening the inventorying, collection, identification and investigation of China’s lichen species diversity, so that they can be protected and sustainably utilized before they are lost to science.