Abstract:
“Sabaragamuwa University Nature Reserve” (SaUNaR) is an institutionally managed
protected area especially for watershed protection, which covers an extent of 13.2 Acres
(about 10% of the total area of the university premises). This protected area provides
different habitats for the rich native biodiversity it possesses. Exotic and invasive alien
species (IAS) of plants marks a rapidly increasing threat to the native biodiversity
around the world, in fact the second most serious threat to biodiversity according to
the Millennium Ecosystem Assessment. Hence, we conducted an opportunistic survey
covering the entire watershed area of the SaUNaR to explore exotic and IAS of plants in
it. The survey recorded 15 exotic and 8 IAS of plants representing 17 families altogether.
Shanon diversity index for exotic and invasive alien species are 1.68 and 2.24 respectively.
Those IAS arranged according to their relative abundance in the study area can be given
as; Leucaena leucocephala (0.33), Acacia auriculiformis (0.32), Clidemia hirta (0.11),
Panicum maximum (0.08),Austroeupatorium inulifolium (0.07), Alstonia macrophylla
(0.04), Lantana camara (0.03) and Sphagneticola trilobata (0.02). The study identifies
the urgent need for implementation of a carefully designed IAS management plan that
should include complete removal (eradication) by uprooting, hand pulling, or cutting
of all above IAS, as all of them show high growth rates and higher level of impacts to
native biota in the site. Exotic species found individually with least impact for native
biota such as Cupressus leylandii, Dracaena fragrans, Ficus benjamina, Citrus sp., Salix
sp. and Artocarpus altilis are recommended to be remained under surveillance due to
their food and shade value for the habitat and/or medicinal and ornamental values for
the humanity.
