The ecosystem of Himalayan region thrive on the land, concealing immense mineral wealth, ranging from the most ordinary clay stones to precious metallic ores. Limestone found in Himachal Pradesh is an important industrial mineral extensively used in steel plants and cement factories and annually about 75,000 million tones is extracted from nearly 603 limestone mines. The state is placed ninth by number of limestone mines [Department of Industries, 2007]. So far, Bilaspur and Sirmour are the two major limestone-producing districts, Mandi district has now received the attention for the same purpose as the Lafarge Cement India, one of the biggest cement industries in the world, proposes to establish a cement plant.

Plants [Flora] and the environment are closely related to each other. Plants compete with each other for nutrition and adjust among themselves either by adaptation or by modifying the environmental conditions that suits them for their continued existence. Thus, they develop a tolerance/adaptation to overcome the adverse conditions. Plant population in a community varies from habitat to habitat. With the change in environmental conditions, the vegetation cover reflects several changes in structure and composition. The component approach involving basic ecological types [i.e. life forms] in vegetation-environment studies permits better resolution of vegetation type, treatment of compositional continuum and succession modeling based on relative advantage of a particular life form. Humboldt [1805], was the first to formulate the concept of life forms, while Golubev [1968], described them as determinants of interactions, structure and dynamics of the components constituting the coenosis. Raunkiaer [1934], expressed climate as the statistical distribution of life forms in the flora of the region. The life form composition appears to vary much less with climate than does species composition [Box, 1981].

Therefore, the present study was undertaken to study the floristic composition in the proposed Alsindi Cement mining area in Mandi District of Himachal Pradesh and understand the life forms.

Himachal Pradesh lies in the lap of the Himalayas, stretching in an area over 55,673 km². The state is administratively divided into 12 districts. Mandi district lies between 31° 13′ 30” -32° 04′ 22” North latitudes and 76° 36′ 08” - 70° 23′ 26" East longitudes. The district is entirely hilly except for some fertile valleys in-between. The district has a total area of 3,950 km², which is 7.1% of the total area of the state. The district lies partly on rocks belonging to the Central Himalayan zone of unknown age and partly on tertiary shale and sand stone. The rock formations in Mandi district lie in continuity to those found in the Shimla Himalaya. They can be classified into the sub-Himalayan series of tertiary rocks and the Himalayan series of metamorphosed sedimentary rocks, and the metamorphic∼cum-igneous rocks of pre-tertiary age. Mandi district is rich in mineral wealth and is famous since historic times for its salt mines. Limestone is the main raw material for cement besides its other uses such as in the production of lime and steel. Mandi district has forest cover of nearly 39 per cent. Deodar, chil, kail, silver fir, etc. are important species found in the district. The forests are scattered throughout the district on the higher slopes. The most important forests are those lying in the Sutlej valley.

The floristic composition was studied in the mining area. The slope was divided along altitudinal gradients i.e., Hill Top [HT], Middle Hill [MH] and Hill Base [HB], so as to record the flora extensively. The flora of surrounding area was enumerated following primary survey and supplemented with secondary sources. The study on floristic composition in order to assess the biological spectrum was carried out for one year from July, 2008 to June, 2009. Floristic composition was studied following suitable ecological methods. Detailed sampling was done at monthly intervals. The life forms, habit and nature of perennating buds of different plant species were recorded in the field and later confirmed with the help of herbaria. Life form classification was done in accordance that by Raunkiaers [1934], and biological spectrum was compared with normal spectrum. The species were assigned to different life form classes: - Ph: Phanerophytes, Ch- Chamaephytes, Hg- Hemigeophytes: Ge; Geophytes and Th- Therophytes.

A total of 76 species were recorded in the area. These include 22 trees, 18 shrubs, 4 climbers, 6 herbs, 4 grasses, 1 sedge and 3 legumes. Some of the important species includes:- Acacia, Albizia, Bauhinia, Citrus, Dalbergia, Mallotus, Pinus, Solanum, Rumex, Amaranthus, Datura, Urtica, Woodfordia, etc. [Table 1]. The survey revealed that most of the trees and shrubs were found at the Hill Base adjoining the village. No trees or shrubs were found to occur in the Middle Hill and Hill Top, except some isolated and scattered shrubs along with some herbaceous flora. As per the field observations, the proposed mining area has very little natural vegetation. In addition, Hill Top and Middle Hill are very steep and are not even amenable to grazing by the local animals. The area does not, in any way, contribute to supplement the sustenance economy or livelihoods of local population due to poor habitat almost bereft with useful vegetation, except limited patches of coarse grasses and scrub vegetation that is extracted as non sustainable fuel. Therefore if mining is allowed to be carried out in this area it will not have any adverse impact on the flora.

[Raunkiaer, 1934], defined life Forms as the sum of the adaptations of plants to climate. According to him:

Geophytes: Plants with parenting parts buried in the substratum

The various species present through out the year were analyzed for different life form classes and percentage distribution among them was computed. The analysis showed that 76 species comprising 40 Ph, 14 Th, and 22 Hg, Ge and Ch were not recorded from the area. The percent values varied as 53% Ph, 18% Th, and 29% Hg. When the present spectrum is compared with normal spectrum in general it was found that phenerophytes, therophytes and hemigeophytes more than the normal spectrum. Geophytes and chamaephytes were completely absent.

The general appearance of a community is caused more by the life-forms of the dominant species than by other characteristics of the vegetation. The proportion of the life forms in an area is a good indicator of its climatic zones [Misra and Misra, 1979]. It is believed to have evolved in direct response to the environment. Singh and Joshi [1983], while studying floristic variations for herbaceous vegetation at tropical region of Pilani and Santvan and Agrawal [1993], while studying the alpine vegetation of Northwest Himalayas, also reported the absence of phanerophytes in their respective studies. The presence of appreciably large number of therophytes in an area is often related to drier soil conditions [Dadhich, 1982]. Bharucha and Dave [1944], investigated a grassland association of Bombay area dominated by therophytes and observed that it was indicator of the influence of man and animals. Pandeya [1964] and Dayama [1987], also observed that overgrazing increases the percentage of Therophytes. The absence of geophytes may be explained by fact that the area is not subjected to adverse climatic conditions. Because, higher percentage of geophytes is an adaptation to with stand long period of adverse climatic condition where storage of food in the form of perenneting organ is an important aspect as has been reported by Santvan & Agrawal [1993], for alpine region of Northwest Himalayan region and by Rawat and Pangety [1985], for snowline vegetation of Central Himalayan [Table:3]. Absence of Chemophytes in the may be due to biotic stress in the area. Similarly, in earlier study lower number of chemophytes have been reported by Singh [1969], for grassland at Varanasi which have been subjected to biotic disturbance. This explains absence of Chemophytes and geophytes in the area.

The area has several algae, fungi, bryopohytes and pteridophytes. Fungi, particularly from ascomycetes and basidiomycetes, are located on the ground or are epiphytical. Lichenes of crustose and fruticose types were present on different substrates. Bryophytes occur in wet areas and on the bark of trees. The commonly occurring ferns in the area are given in Table 2.

The Present study reveal that the phenerophytes and therophytes have higher percentage value when compare to the normal spectrum of Raunkiaer [1934]. The geophytes and chamaehytes are absent. The higher number of therophytes may be due to poor soil condition along with biotic interference. The higher number of geophytes is an adaptation to severe climatic condition which is not the case in present study. It can be concluded that in the region not only the climate but the biotic interference has also, changed the life form composition of the area. This is in accordance with the finding of Warming [1909], who emphasized that in the flora of a region great changes are brought about by the biotic pressure. Therefore, Primary strategy of plants in the region remains their survival, resulting in evolution of a wide range of behavioral and life form patterns at species level, under varying biotic disturbance to enable them to occupy various ecological niches in all kinds of climate.

References