Effect of intraspecific functional traits, soil and competition on tree growth
Student name: Ms Sharada Ramadass
Guide: Dr Sudipta Chatterjee
Year of completion: 2017
Host Organisation: National Centre for Biological Sciences (NCBS), Bengaluru
Supervisor (Host Organisation): Dr Mahesh Sankaran
Abstract: Functional traits are a useful measure to explain ecological performance of species. They help
understand community structure and ecosystem dynamics processes at play in response to
environmental factors. These traits are variable between and within species. Most ecological studies
do not focus on intraspecific trait variation, instead using mean trait values to explain the species
functions and interactions within the community. Large variation in traits within species may break the
underlying assumption of homogeneous populations of individuals and greatly impact community
dynamics, especially under changing climatic conditions. In this study, we look at intraspecific trait
variation in trees, across a wide girth range, in a tropical forest ecosystem, and its impact on growth
in conjunction with other biotic (such as competition from conspecific and heterospecific neighbors)
and abiotic (soil) factors. The results showed wide variability in traits within and between species.
Some traits variations were comparable to others across some species while others were not.
Competition and abiotic parameters outperformed trait variation in explaining growth over a 2-year
period. The results indicate that in dense tropical forests with competition and possibly limiting soil
conditions, for a wide variation in tree age classes, short term growth may not bring out the
significance of intraspecific trait variation in trees. Longer term growth data as well as extensive
sampling of individuals may be necessary to capture the influence of traits on growth. It is therefore
important to have long term monitoring of traits and growth in trees in such ecosystems to understand
the community performance from the view of individual trees.
Keywords: intraspecific, variation, functional traits, trees, growth
