In England, the Nature Conservancy Council takes the help of the informed public who volunteer to make periodical and systematic record of the density of populations of species in the wild habitats. These records form the basis to assess the changes in the species density and distribution. This helps in monitoring biodiversity in terms of habitats and/or individual species. India being so vast in area and the number of species, needs such public support that can probably be drawn from high school or college students after imparting basic training. Such a suggestion, in a different context, was made by Gadgil (1996).

        A Status Survey is needed to determine the conservation status and needs of individual species and habitats. A Survey is a one time recording. Surveillance is repeated surveys. Census is repeated recording of population densities of a single species including fluxes of births and deaths. Clearly a lot of planned work is involved in monitoring biodiversity.

Goldsmith (1993b) advocated that priorities should be established before rushing to monitor ecosystems and suggested the following:

a) Conservation evaluation: species of international importance take priority over those of national importance. These in turn take priority over those of regional importance which take priority over those of local importance;

b) Sensitivity: this reflects the inherent sensitivity of some species or biotopes and should take priority over more robust ones;

c) Vulnerability: this reflects the resilience of some species and biotopes to external forces such as desiccation, salinisation, over-grazing, pollution, etc.;

d) Simplicity: if the monitoring procedures are simple and easy to carry out, it is more likely to be conducted than otherwise. Also, it is more likely to be continued when staff change or funding becomes difficult; and

e) Cost effectiveness: inexpensive monitoring programmes are more likely to run until completion than expensive ones.

In order to evaluate the biotopes or species being studied, it is necessary to have extensive survey data for other comparable areas to set the target one in context. Estimates of man power and costs are important as also the techniques of gathering and recording data.

If we compare the global situation with that in India, the distressing and inescapable conclusion would be that we did not even make a beginning of understanding the magnitude of our biodiversity conservation problems.

CONSERVATION NEEDS OF INDIAN MEDICINAL PLANTS

       Charaka advocated that any substance is a medicine, if we find a suitable medicinal use for it. Species of plants have become medicinal plants when a therapeutic use was discovered for them. Besides, what is an important medicinal plant today may not remain to be the same later on and some other species may become important in course of time. The medicinal plants are like the other economic plants which are not cultivated. These two groups of plants differ from the wild plants in the matter of commercial demand. Nevertheless, several medicinal plants are also collected from the wild habitats while some are cultivated. In practice, there should not be any difference in our approach in conserving medicinal and non-medicinal plant species. Such a non-discriminatory approach for conservation action will be in our future interests.

       The following species of medicinal plants from India have been considered to be ‘endangered and threatened’ for over a decade (Ayensu, 1986): Acorus calamus, Alpinia galanga, Commiphora wightii, Dendrobium nobile, Dendrobium pauciflorum, Dioscorea deltoidea, Diplomeris hirsuta,Gentiana kurroo, Nelumbo nucifera, Paphiopedilum druryi, Podophyllum hexandrum, Rauvolfia serpentina, Santalum album, and Saussurea lappa. A very large number of other species of medicinal plants can be added to this list, as for example Saraca asoca, Picrorrhiza kurroa, Costus speciosus, Berberis aristata, Gloriosa superba, etc.

       The Medicinal Plant Specialist Group of the SSC, met in September 1996 in Nairobi, and resolved to identify ‘Top 50’ medicinal plant species for conservation action (Cunningham et al., 1997). These Group listed five steps to identify both global and regional priority species.

The Indian Subcontinent Plant Specialist Group that met in January 1998, identified the following species of medicinal plants for detailed study and protection:

Abrus precatorius, Adhatoda vasica, Centella asiatica, Costus speciosus, Gloriosa superba, Rauvolfia serpentina, Saraca asoca, Strebles asper, Tribulus terrestris and Withania somnifera.

       On a sensitive and important issue like medicinal plants, we need very accurate data regarding the past and present distribution, plant population density in various localities, the current commercial demand and future projections, practices of collection, the factors that affect the population survival, etc. We hardly have any systematic information on these lines.

       There have many estimates on the commercial demand and the costs of Indian medicinal plants but these were not based on any uniform or scientific criteria. Nevertheless, they indicate that the demand is very heavy and detrimental to species survival. The following are some examples of the quantities of medicinal plants (in tonnes) recently recommended for procurement in the Chittoor district of Andhra Pradesh (Hemadri and Rao, 1998):