On the relationships among diversity, productivity and climate from an Indian tropical ecosystem: a preliminary investigation

The relationships among diversity, productivity and climate are complex, especially in tropical ecosystems; and are less studied. We studied here the bi- and tri-partite relationships between and among the plant diversity, productivity and climate variables (i.e., temperature, precipitation and moisture) in a tropical ecosystem in India by analyzing three forest types for the year 2010. Comparison of productivity (Carnegie–Ames–Stanford Approach model derived-net primary productivity, NPP) and climate condition with respect to 2001 showed significant increase in NPP and temperature and overall decrease in precipitation and moisture condition in last decade. The NPP for sal forest ranged from 579.4 to 1,142 for the year 2001 and 557.2 to 1231.6 g Cm−2 year−1 for the year 2010. The mean monthly temperature varied from 18 to 21.8°C and 26 to 27°C; and the annual precipitation varied from 15 to 45 and 32 to 76 cm/year for the year 2001 and 2010 respectively. Strong correlation was observed between monthly mean temperature and productivity during 2001, while a decrease was observed during the year 2010. The ecosystem has shown a trend of rapid drying in last decade, triggering more detail studies for understanding of the eco-climatology. In general, sal forest, a natural forest sowed higher diversity and productivity followed by mixed deciduous (MD) forest and teak plantation. Though, areas with higher NPP are well correlated with higher temperature, precipitation and moisture; they seem to be related to species density rather than diversity. However, there is a need to have year-on-year assessments in order to ascertain if this difference represents a real phenomenon rather than an artefact of sampling. The pilot study helps in understanding the complex relationships and is very useful in the fast changing climate.