Browsing by Author "Perera, S.J."

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An assessment of the avifaunal diversity in Hapugastenne estate of Ratnapura District, Sri Lanka
(Department of Zoology and Environmental Management, University of Kelaniya, Sri Lanka, 2017) Fernando, G.K.; Perera, S.J.
An avifaunal survey was conducted at Hapugastenne Tea Estate (1302ha), Ratnapura, Sri Lanka from November to December 2015 with objectives of assessing the bird diversity within different habitats and documenting threats to biodiversity. Bird populations were sampled in 39 line transects and 17 point counts for terrestrial and aquatic habitats respectively representing eight habitat strata (tea fields, home gardens, scrublands, secondary forests, natural forests, stream-side vegetation, riverine forests, and water-logged areas) within the estate, replicated in its nine divisions. Transects were conducted during the morning between 07:00 and 09:00 hrs. A total of 91 species, including nine Sri Lankan endemics and nine winter visitors were recorded, which included one globally and six nationally near threatened species. Estimates of relative abundance indicated a high degree of rarity, with only few abundant species, the red-vented bulbul being the most abundant. Among the habitats, the highest species richness (39) was recorded in stream-side vegetation where Simpson’s diversity index (0.947) was also the highest, while the Shannon-Wiener diversity index (H’=3.247) is marginally second to tea fields (H’=3.382), where the evenness was the highest (J=0.994). Interestingly, the Shannon-Wiener diversity and the evenness of the secondary forest fragments were comparable to those of home gardens (H’=2.591; J=0.795 and H’=2.515; J=0.791 respectively). The results of the feeding guild analysis indicated a greater abundance of the insectivore guild was greater in tea field than in other habitats. In contrast, the relative abundance of frugivore guild was higher in the natural and secondary forests. Cluster analysis indicated a highly dissimilar species composition in scrublands compared to other habitats, while tea fields and home gardens were very similar in their avifauna. The study revealed that this managed landscape provides a diversity of niches maintaining the natural biodiversity to a certain extent. Nevertheless, 14 alien invasive species (nine plants and five animals) were identified from the area among several other threats to the biodiversity. Increasing plant diversity, introduction of shade trees and connecting remnant natural habitat patches via stream reservations are recommended to conserve and enhance the avifaunal diversity in the study area.
Corrigendum to "Larvicidal Potential of Five Selected Dragonfly Nymphs in Sri Lanka over Aedes aegypti (Linnaeus) Larvae under Laboratory Settings"
(Hindawi Publishing Corporation, 2019) Samanmali, C.; Udayanga, L.; Ranathunge, T.; Perera, S.J.; Hapugoda, M.; Weliwitiya, C.
ABSTRACT: [This corrects the article DOI: 10.1155/2018/8759459.]. Erratum for, Larvicidal Potential of Five Selected Dragonfly Nymphs in Sri Lanka over Aedes aegypti (Linnaeus) Larvae under Laboratory Settings. BioMed Research International. 2018; 2018:8759459.
Larvicidal potential of five selected Dragonfly Nymphs in Sri Lanka over aedes aegypti (Linnaeus) larvae under laboratory settings.
(Hindawi Pub. Co., 2018) Samanmali, C.; Udayanga, L.; Ranathunge, T.; Perera, S.J.; Hapugoda, M.; Weliwitiya, C.
INTRODUCTION: Limitations in breeding source reduction practices, development of insecticide resistance in mosquitoes, and ill effects of chemical controlling methods on human and ecosystem health have motivated Sri Lankan authorities working for dengue control to seek for alternative, ecofriendly, and sustainable approaches for controlling of Aedes vectors, to manage dengue epidemics. The present study attempted to investigate the predation efficiency of locally available dragonfly nymphs over Aedes aegypti under laboratory conditions, aiming to evaluate the potential of using dragonflies as biocontrol agents against dengue. METHODS: Nymphal stages of five locally abundant dragonfly species were collected from different stagnated water bodies in Belihuloya area. After morphological identification, a well grown individual of each species was starved for 12 hours and introduced into a glass tank containing 1L of pond water with 200 larvae (4th instar) of Aedes aegypti. Number of larvae survived in the tank was enumerated hourly up to 48 hours. In case where >75% of larvae are consumed by dragonfly nymphs, additional Ae. aegypti larvae were introduced into such tanks. Experiment was repeated for five times. Same procedure was followed with different stages of growth of the dragonfly nymphs characterized by the highest predation rate. General Linear Model followed by Tukey's pairwise comparison was used for statistical analysis. RESULTS: The predation rates of different dragonfly species varied significantly (p<0.05), whereby Anax indicus (110±7.14 per day) indicated the highest, followed by Pantala flavescens (54.07±5.15) and Gynacantha dravida (49.00±11.89), while Tholymis tillarga (23.47±2.48) had the lowest. Further, significant variations in the larval predation were found among different maturity stages (10-20; 25-35; and 35-45 mm in body length) of Ana. indicus (p<0.05). Regardless of statistical significance, a relatively higher larvicidal activity was observed at dusk than in dawn. Conclusion. Ana. indicus, which is characterized by the highest predation rate, and P. flavescens that has the widest geographical distribution within Sri Lanka along with a notable predation efficacy could be recommended as potential candidates for field trials in biological control of dengue outbreaks via suppression of Ae. aegypti larvae.