Seed Dispersal Potential of Asian Elephants (Elephas maximus) in Kumaragala Forest Reserve, Matale District, Sri Lanka

Abstract

Elephant foraging directly affects the growth, survival and vegetation dynamics of forests.
They consume a variety of plants including trees, vines, shrubs and herbs. Even though
elephants are considered as important seed dispersal agents, very few studies have been
carried out to study the seed dispersal ability of elephants in Sri Lanka. Hence, this study was
conducted in a natural forest and a bordering chena cultivation area in Maragamuwa
(70070‟N and 80065‟E), within Kumaragala Forest Reserve, from September 2014 to
February 2015 to determine the seed dispersal capability of elephants. Three boli were
collected randomly from each dung pile and rest were kept in the field and observed until the
decomposition was complete. Collected boli were broken and visible seeds were identified by
comparing with a reference seed collection. Unidentified seeds were cultivated in sterilised
soil. Broken boli were kept in a greenhouse and watered to identify the plants whose seeds
were invisible to the naked eye.

The study found a total of 84 dung piles and 252 boli were collected from those piles. Fifty
three piles out of 84 (63.09%) contained seeds or seedlings of one or more plant species. A
total of 22 plant species belonging to nine families were observed to germinate from boli.
Among these 22 species, 12 species were cultivated (representing 54.55% of the plant species
germinated from boli) and 10 (45.45%) were non-cultivated plant species. Seventeen plant
species from chena cultivation area and six species from natural forest were found. Careya
arborea and Megathyrsus maximus were the most frequently found seeds and seedlings.
Among the cultivated plants, climbers (41.67%), shrubs (8.33%), and herbs (50%) were
found, and among the non-cultivated plants trees (60.00%), herbs (4.55%) and shrubs
(13.64%) were found regularly. It is interesting to note that herbs formed 50% of the
cultivated plants, while they formed only 4.55% of the non-cultivated plants germinating
from elephant dung boli. The results from this study could be used to develop habitat
enrichment programs for wild elephants that help in mitigating the human-elephant conflict,
which is now becoming a serious conservation issue for the Sri Lankan elephant.

Keywords: Mega-herbivores, Foraging, Elephant dung, Human-elephant conflict, Conservation