Articles written in Journal of Biosciences
Volume 24 Issue 4 December 1999 pp 491-498 Articles
Climatic implications of δ13C and δ18O ratios from C3 and C4 plants growing in a tropical montane habitat in southern India
Geeta Rajagopalan R Ramesh R Sukumar
The stable carbon and oxygen isotope ratios in cellulose of C3 and C4 plants growing on the surface of a montane peat bog in the Nilgiri hills, southern India, were measured. The mean monthly δ13C values in cellulose of both C3 and C4 plants are found to be significantly related to rainfall, while the δ18O values are sensitive to changes in maximum temperature and relative humidity of the region. Further, higher δ18O values were observed in C4 plants compared to C3 plants, suggesting that C4 plants are probably less sensitive to relative humidity as compared to C3 plants and are able to photosynthesize even during drier conditions. The plant isotope-climate correlations thus established can be used for reconstructing the past temperature and rainfall conditions of the tropics from the isotopic ratios of peat deposits, derived from a mixture of C3 and C4 plants in the region.
Volume 27 Issue 5 September 2002 pp 521-528 Articles
The effect of some ecological factors on the intestinal parasite loads of the Asian elephant (
Some ecological factors that might potentially influence intestinal parasite loads in the Asian elephant (
Volume 31 Issue 5 December 2006 pp 651-669
Patterns of tree growth in relation to environmental variability in the tropical dry deciduous forest at Mudumalai, southern India
Cheryl D Nath H S Dattaraja H S Suresh N V Joshi R Sukumar
Tree diameter growth is sensitive to environmental fluctuations and tropical dry forests experience high seasonal and inter-annual environmental variation. Tree growth rates in a large permanent plot at Mudumalai, southern India, were examined for the influences of rainfall and three intrinsic factors (size, species and growth form) during three 4-year intervals over the period 1988–2000.
Most trees had lowest growth during the second interval when rainfall was lowest, and skewness and kurtosis of growth distributions were reduced during this interval. Tree diameter generally explained <10% of growth variation and had less influence on growth than species identity or time interval. Intraspecific variation was high, yet species identity accounted for up to 16% of growth variation in the community. There were no consistent differences between canopy and understory tree growth rates; however, a few subgroups of species may potentially represent canopy and understory growth guilds. Environmentally-induced temporal variations in growth generally did not reduce the odds of subsequent survival.
Growth rates appear to be strongly influenced by species identity and environmental variability in the Mudumalai dry forest. Understanding and predicting vegetation dynamics in the dry tropics thus also requires information on temporal variability in local climate.
Volume 48, 2023
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