The vegetation composition, diversity and structure of tropical montane forests in the Palni Hills: Analyzing the impact of disturbances
Student name: Ms Charvi Tanya Dutta
Guide: Dr Joachim Michael Schmerbeck
Year of completion: 2013
Host Organisation: University of Freiburg, Germany
Supervisor (Host Organisation): Dr Stefanie Gartner
Abstract: The species composition and tree structure in the low disturbed and high disturbed areas of the Palni
Hills was studied. It was hypothesized that under high disturbance the species composition and
diversity of the forest is negatively impacted. To understand the role of exposition in the species
composition and structure, comparisons were made between the north and south exposed sites present
with the high disturbance and low disturbance areas of the study. The study reveals that the species
composition was significantly different for the high and low disturbed areas with the high disturbed
and low disturbed areas consisting for herb rich and shrub/tree regeneration rich vegetation
respectively. The diversity, richness was higher for the low disturbed areas in the lower and middle
layers while the upper layer consisted for a similar diversity and richness in both the areas. The north
and south exposition did not influence the species composition or diversity in the low disturbed areas
but for high disturbed areas there was significant difference between the two expositions. The high
disturbed north expositions had lower diversity and very less tree regeneration. The density of
regeneration also was found to be almost double for the low disturbed areas as compared to the
high disturbed areas. The high disturbed sites showed absence or low density of middle layer. The low
disturbed areas were dominated by regenerating trees like Cinnamomum wightiana, Gomphandra
coriacea and Litsea wighiana in the lower and middle layer while the high disturbed areas were
dominated by herbs and shrubs like Ageratina adenophora, Solanum pseudocapsicum and Lazianthus
accuminatus. The high disturbances in the present were the reason for the reduced diversity in the high
disturbed areas while high disturbances in the past were the reason for the dominance of pioneers
and similarity between the HD and LD areas in the upper layer. The study showed that high levels of
disturbances had a negative impact on the diversity and structure of the forest, thus proving the
hypothesis correct. But for a better understanding undisturbed sites need to be identified and studied
also.
Keywords: Anthropogenic, disturbance, Shola forest, diversity and structure.
