COMMENTARY CURRENT SCIENCE, VOL. 94, NO. 8, 25 APRIL 2008 976 Need for creation of lichen gardens and sanctuaries in India D. K. Upreti and Sanjeeva Nayaka The habitat loss, increasing air pollution, changes in the microclimatic conditions and uncontrolled harvest have become the major detrimental factors for lichen diversity in India. Propagation of lichens by means of tissue culture method proved to be uneconomical and their re-introduction into the field has been unsuccess- ful. Hence declaring lichen-rich areas as ‘lichen sanctuaries’, enriching the existing botanical gardens with lichens and creating lichen gardens would be effective methods to conserve them in their natural habitats. Such sanctuaries and gardens would be unique in the world; apart from conservation, they also serve as educational and recreational sites. The fast pace of urbanization and indus- trialization in recent years is responsible for a perceptible decline in the vast ranges of forest areas in different parts of the world. The rate of decline in the Indian Himalayas is quite fast compared to that in other areas. The leading factors for the loss of biodiversity in the Himalayan region are the agricultural practices, urbanization, construction of roads and buildings on hills, mineral exploration, hydroelectric projects, and excessive use of firewood. In the last few decades large tracts of forest cover have been depleted in and around the human settlements in the Himalayas. In India, the lichens are still in use as medicine, spice, dye and incense mate- rial. The easily accessible areas of the Himalayas are exhaustively exploited for collection of commonly occurring lichens for commercial exploitation. Information regarding the commercial, ethnobotanical utilization and use of lichens in Ayur- vedic and Unani systems of medicine in India is well documented 1–5 . Upreti 6 has discussed in detail, the different factors responsible for the loss of lichen diversity in India. The disappearance of sensitive lichen species due to changes in micro- climatic conditions and air pollution is evident in the recent studies conducted in the cities of Bangalore and Kolkata 7,8 . Use of herbal drugs in recent years has created an increasing demand for medi- cinal herbs. The medicinal plants in the easily accessible areas in nature are be- ing exploited exhaustively. Several local and outside traders are indulging in the indiscriminate collection of these plants, that sometimes no propagules are left in nature for regeneration. Lichens are pro- mising source of several biologically active secondary metabolites with antibiotic, antimycobacterial, antiviral, anti-inflam- matory, analgesic, antipyretic, antiproli- ferative and cytotoxic acitivites 9,10 . However, lichens are slow-growing organisms and take several years to get established in nature. Lichens that use to occur as thick growth on tree trunks in the lower temperate regions, have now become scanty due to uncontrolled har- vest. Hundreds of bags of lichens are be- ing exported from different foothill areas of the Himalayas 5 . A number of areas have been declared as National Parks, Wildlife Sanctuaries and Biosphere Reserves in recent years for the protection of wildlife; however, cryptogams such as lichens are still treated as waste or non-timber forest product. In alpine regions, junipers, rho- dodendrons and other shrubs which rep- resent a growth of over hundred years are destroyed by the tourists for bonfires and lichens growing on them are also de- stroyed unknowingly. Lichen resources in contrast to other natural resources in India are exploited at fast rate and there are no efforts to replenish them. Apart from creating awareness among common people, it is also important to undertake serious con- servation measures to improve the lichen resources of the country. In vitro culture of lichen symbionts or resynthesis of whole thallus in bulk quantities appears to be an alternative to prevent decline of the lichen population under natural con- ditions. In recent years, highly efficient methods have been established for the cultivation of isolated symbionts and the lichen tissue itself 11–13 . Mycobionts grow faster in in vitro culture and have the ability to produce the same secondary metabolites as in composite thallus. Apo- symbiotically and axenically grown my- cobionts can replace naturally grown thalli to meet the demand of large quantities of biologically active lichen substances 14 . Also, the development of bioreactors for cultures and genetic manipulation would facilitate large-scale production of lichen metabolites 10 . In India several lichens have been successfully in vitro-cultured and standardized for their physiological conditions 15–22 . However, it should be noted that multiplying lichens by means of tissue culture method is uneconom- ical, time-consuming and has also proved to be unsuccessful in several cases 23 . Unlike other plants, success rate of re- introducing cultured lichen thallus into the field is also low. Hence, in situ con- servation by declaring lichen-rich areas as ‘lichen sanctuaries’, enriching the ex- isting botanical gardens with lichens and creating lichen gardens would certainly be effective methods to protect lichen populations in their natural habitat. Enriching botanical gardens with lichens Arvidson 24 has discussed in detail the importance of botanical gardens for lichens in the Asian tropics. In certain areas of the world, botanical gardens are the best place for lichenological studies as they have well-developed lichen flora. The cultivation of the cryptogams, par- ticularly the indigenous ones, are possi- ble in different available habitats of both the tropical and temperate areas. Several factors which favour a diverse lichen vegetation in botanical gardens are the long ecological continuity, variety of habi- tats, less polluted pockets in the centre of the garden, and presence of rare and en- dangered plants that provide an opportu- nity for many lichen taxa to colonize. Many botanical gardens already func- tion as genetic banks for vascular plants, but in the case of non-vascular plants such functions are not known. For in situ conservation of threatened lichens,