HABITAT UTILISATION PATTERN OF Lantana camara IN UDAWALAWE NATIONAL P,ARK IN SRI LANKA

Abstract

Lantana camara, of the family Verbenaceae is native to the tropical and sub tropicalregions of Central and South America. It grows in a wide range of habitats, from exposeddry hillsides to wet heavily shaded gullies. It was introduced to Sri Lanka in 1926 throughthe Royal Botanic Gardens and currently it has spread across the island significantly andhas become an invasive species in most of the habitats including the Udawalawe NationalPark. Through its invasive nature it has become a threat to fauna and flora of the Park dueto habitat invasion and loss. Therefore, the main objective of this study is to assess thehabitat utilization pattern of L. camara in the Park.

For this, the extent of the species in the 3 selected habitats of the Park ie. Scrub grassland,Medium height scrub and Scrub forest transitions was studied using field survey using GPSmstruments. This data was mapped subsequently in order to get an overall idea of thehabitat utilization of the species in the Park. Further, the relative abundance of this speciesin each of the 3 habitats selected was studied using 10 x 10 m quadrates replicated 3 timesfor better accuracy. Field observations were carried out in L. camara trees on the followingparameters; presence of flowers and seeds on the tree, time taken to start flowering, seeddispersal mechanism, seed germination and spreading ability. Seeds were also germinatedin the green house of the University of Sri Jayewardenepura to assess the germinationperiod and germination energy.

The results showed significant variation was observed between the habitat types sampled inthe extent of L. camara; the figures being 75% in the Scrub grassland, 65% in Mediumheight scrub and 45°;(, being in the Scrub forest transitions. When these results weremapped, it showed 20% invasion of L. ccmara in the Park especially into the vegetationtypes sampled in the study ..When taken as an overview, the main road and Veheragolla,Seenuggala, Mau ara, Thirnbiriyarnankada and 5th mile post are the most densely andcontinuously distributed areas.

The relative abundance and height of L. camara was highest in the Medium height scrubgrassland (92%) while the lowest was observed in the Scrub forest transitional area (87%).The species produced large number of flowers and seeds (20 - 30/cluster). The germinationability of the plant was very high (85 (~,O Therefore, the present study highlights theinvasive nature of the plant especially in open scrub areas and the need to effectivelymange the same to secure the biodiversity of the Park.