No abstract

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Bats spend more than half of their life in roosts, where key life events transpire. Therefore the availability and selection of roosts are important to bats everywhere, and may limit their ability to exploit every habitat, including agricultural landscapes such as paddy fields, orchards and tea plantations. This study aimed to investigate the day roosts used by insectivorous bat species in tea plantations of Sri Lanka. We surveyed 18 tea plantations where we recorded a total of 44 roosts involving five families and nine species of bats (Hipposideros galeritus, Hipposideros lankadiva, Hipposideros speoris, Rhinolophus beddomei, Rhinolophus rouxii, Megaderma spasma, Pipistrellus ceylonicus, Pipistrellus coromandra and Miniopterus cf. fuliginosus). Most (26) of the recorded roosts were geomorphic, (11) were anthropogenic, and (7) were in vegetation. H. lankadiva and M. cf. fuliginosus are the only species known to roost exclusively in geomorphic roosts; all others were opportunistic. Although protecting bat roosts is crucial for their conservation, it is challenging in view of existing tea management practices. Therefore, natural roosts should be maintained and protected. The introduction of artificial roosts might increase the number of bats able to forage over tea plantations and maximize their consumption of agricultural pests, thereby increasing tea production.

A survey on birds was conducted at Mattakelle Tea Estate with the objective of assessing the significance of a given tea plantation ecosystem in maintaining avifaunal diversity. Seven different habitats were identified in the ecosystem namely home garden, seasonal stream, small scale reservoir, Eucalyptus forest, wetland, tea field and secondary forest. The monitoring was conducted from January to June 2010 using line transect method. 28 counts were made for each habitat. Besides, activities of birds, feeding habits and food recourses were observed. 61 species of birds including 9 species of endemics and 10 species of migrants were recorded. One globally threatened species Kashmir Flycatcher (Ficedula subrubra) and 12 nationally threatened species were observed. Among the habitats, the highest species count of 62% was recorded in home garden habitat where Shannon index (H') = 3.03 and Evenness (J) =0.46. Species diversity and the evenness of the secondary forest were comparable to tea field indicating H'= 2.86 and J=0.43; H' =2.77 and J= 0.46 respectively. The avifaunal diversity was relatively low in the rest. The study revealed that each of the habitats provided unique niches and supported maintenance of natural diversity. Vegetation structure and the complexity of the ecosystem in tea plantations play a vital role in sustaining avifaunal diversity. Several conservation measures such as increasing plant diversity, introduction of shade trees, conduct of good agricultural practices and prevention from setting fire are recommended to protect and conserve avifaunal diversity.