Composition of Life forms and Biological spectrum along climatic gradient in Rajasthan, India

Analysis of life forms of the vegetation in arid, semi-arid and sub-humid regions of Rajasthan, a north-west state of India, was carried out based on the data collected from the field. The floristic and vegetation biological spectra of four study sites (Jaisalmer, Ajmer, Sariska and Mt. Abu) were compared. Analysis of life form spectra revealed the most striking feature of higher differentiation in proportions of therophytes along climatic gradient using vegetation spectrum. The proportion of therophytes and phanerophytes are highly variable across the sites indicate influence of climate. Biological spectrum of the four study sites has been compared with Raunkiaer's normal spectrum to know the phytoclimate of that region. Jaisalmer, Ajmer and Sariska represents tropical arid climate, while Mt. Abu of tropical moist climate. The present study recommended to use vegetation biological spectrum because of proper representation of life forms of a given area. The disadvantage of floristic biological spectrum is underestimation of dominant vegetation expression and identical value to the rare speCIes.