SPATIOTEMPORAL SEED BANK FLORA OF PERISTROPHE PANICULATA COMMUNITY IN A SEMI ARID DESERT OF KARACHI, PAKISTAN

Abstract

Seed bank studies of Peristrophe paniculata was carried out for two consecutive years at two different sites. Although, both the sites were dominated by P. paniculata, however differ in vegetation pattern. Site ‘A’ possessed populations of annuals fully exposed to sunlight. While, site ‘B’ possessed annuals along with perennials located in somewhat shady area. Input to the seed bank was mainly determined by the seed dispersal. Persistent seed bank was observed in annual plant species with increasing numbers in the third collection (i.e. after seed dispersal). On the other hand, perennial plants mostly exhibited transient nature of seed bank, with no or low numbers in some collections. Significant difference in seed numbers was observed on temporal and spatial scale. Seed densities were higher in the samples collected before rainfall and after dispersal of seeds at both the sites in both the years. High degree of similarity was observed between above and below ground vegetation; however this similarity was more pronounced at site ‘B’ which was located in shady area, thus providing better soil moisture conditions for seed germination. Moreover, above and below ground vegetation was diverse and flourished in 2013, due to high germination rates, followed by heavy summer rains, providing ample amount of moisture along with high temperature. This study can be used to predict the above ground vegetation and vise versa.