Long-term study on invasive behavior of Myroxylon balsamum in the Udawattakele forest reserve, Kandy, Sri Lanka
By: Gamini Hitinayake, Vigini Gunawardane, Haritha Wedathanthri
Key Words: Invasive species, Myroxylon, Udawattakele forest.
J. Bio. Env. Sci. 9(4), 262-271, October 2016.
The objective of this study was to estimate the changes in the vegetation structure and species composition of the Udawattakele forest reserve due to Myroxylon balsamum invasion during the twelve year period from 1998 to 2010. Species composition of the upper story and under story were evaluated through measuring Relative Importance Value (RIV) of species in the Myroxylon invaded parts of the forest, initially in 1998 and then in 2010. A map was drawn to show the distribution and abundance of Myroxylon in the Udawattakele forest reserve. Germination of Myroxylon seeds were evaluated under different light intensities. Results showed that seeds of Myroxylon are able to germinate under a wide range of conditions from full sunlight to complete darkness. The results of the forest inventory showed that Myroxylon invasion has caused significant reduction in the species diversity in the forest. Myroxylon dominates the under story even when a few mother trees occur in the over story due to its prolific self-regenerating ability. Further, it was found that, Myroxylon had infested some new areas of the forest during the 12 year period between 1998-2010. Hence control measures have to be applied without any delay. The over story species composition and diversity of the Myroxylon invaded areas of the forest has not changed significantly (P=0.05) during the 12 year period. However, species diversity of the under story has increased (P=0.05). This was caused mainly due to self-thinning of Myroxylon and arrival of Mahogany, another species spreading rapidly in the Udawattakele forest reserve.