Plant diversity and dry-matter dynamics of peri-urban plant communities in an Indian dry tropical region

The emergence of variety of land-use changes due to continuous anthropogenic pressure in peri-urban areas may concomitantly result in modification of the structure of associated plant communities for their sustainable growth. In the present study, plant diversity, and above- and belowground biomass distribution among species were investigated to understand their dynamics across different season, soil, and site conditions in a dry tropical peri-urban region in India. From four study sites that covered contrasting land uses: abandoned brick kiln (ABK), grazing land (GL), Kali river bank (KRB), and agricultural land (AL), a total of 360 monoliths were randomly extracted in three seasons, and dry weights were estimated for aboveground and belowground parts of species individuals. Seasonal soil samples of the sites were analyzed for physico-chemical characteristics. Of the total 87 recorded species that were mainly annual weeds and ruderals, 77% were forbs and 23% grasses. The ranges of plant biomass recorded across all sites and seasons were: aboveground 228–738 g m⁻², belowground 83–288 g m⁻², and a total of 344–1,026 g m⁻². The dominance of species differed between above- and belowground; some species dominated only above- or belowground, and others dominated in both layers. Above- and belowground biomass of the sites, differential community-biomass allocation to above- and belowground parts and species dominants varied significantly with site and season. ABK and AL sites showed lower species diversity and soil nutrients compared to GL and KRB sites. Belowground biomass significantly declined with increasing soil organic C and total N, indicating altered dry matter allocation under resource-scarce habitat conditions. Higher diversity occurred at both low- and high-biomass sites, reflective of enhanced ability of these plant communities to exploit resources maximally in spatio-temporal pattern.