Abstract:
The vast majority of the virgin forest in the Central Region in Sri Lanka, including
that in the Knuckles Mountain Forest Range (KMFR), has been cleared for
agricultural purposes. As a result of these uncontrolled anthropogenic*agricultural
practices, the sub-montane forest in the KMFR is now highly fragmented and
drastically reduced in area. To investigate whether the secondary forests facilitate
the conservation of amphibians and to study patterns of recolonization of anurans
following forest habitat alteration, we undertook field research in the KMFR.
Using 10 sites for each of the virgin forest, on-going tea plantations, and three
successional stages following abandonment of tea plantations, we investigated
how the secondary forests have influenced patterns of recolonization of anurans
following forest habitat alteration. Our investigations, conducted from April 2008
to April 2009 and incorporating two monsoon and two inter-monsoon seasons,
resulted in us encountering 237 post-metamorphic anurans representing 21 species
arrayed among the families Bufonidae, Microhylidae, Nyctibatrachidae, Ranidae
and Rhacophoridae. The lowest species richness (three species) was encountered at
sites currently in production, for all seasons. Six and eight anuran species were
recorded from the middle and late successional stages (secondary forest habitats)
respectively. The species richness of anurans was highest (eleven) in the submontane
virgin forest for all seasons. Our secondary successional studies revealed
a high incidence of recolonization of abandoned agricultural lands by anurans, and
accordingly our results indicate that the secondary forest might play a substantial
role in the conservation of biodiversity in tropical areas, and in particular in the
KMFR. Furthermore, the positive relationship between anuran species richness
and the successional stages of this study reveals that this mountain range has to be
managed carefully. Prevention of further destruction and close regulation of
human impact on the undisturbed virgin forest in the area are called for. In light of
evidence of recolonization patterns of anurans in abandoned tea plantations and the
recovery patterns of the vegetation, our study emphasizes the importance of
conserving these diminishing and invaluable habitats, and hopefully will prompt
further research on the wildlife of this area.
