Journals Information
Advances in Zoology and Botany Vol. 11(6), pp. 443 - 453
DOI: 10.13189/azb.2023.110605
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Long-term Population Trends of Migratory Shorebirds- A Case Study from Manoli Island, the Gulf of Mannar Biosphere Reserve, India
Byju H 1,*, S Balachandran 2, S. Ravichandran 1
1 Centre of Advanced Study in Marine Biology, Annamalai University, Parangipettai - 608 502, Tamil Nadu, India
2 Bombay Natural History Society, Mumbai-400023, India
ABSTRACT
Declining shorebirds happen globally due to changes in habitat and anthropogenic pressures. The shortest flyway (Central Asian Flyway-CAF) hosts significant shorebirds that winter in the Indian subcontinent lacks long-term studies on population size and trends. This paper is based on three-decade population monitoring of migratory shorebird species carried out on the uninhabited coral island of Manoli in the Gulf of Mannar Marine National Park (IBA) located along the southeast coast of India. The site is of importance due to its proximity to Sri Lankan Important Bird Areas (IBA). Direct observation and total counts were done during 2017-2019 and compared with earlier data from 1985-1988 and 2005-2007. Species diversity, Pielou's evenness and dominance index were also estimated. The similarity between shorebird species abundance was approached by cluster analysis and non-metric Multi-Dimensional Scaling ordination (NMDS) considering the study period as pre-2000 and post-2000 for analysis. The Shannon Diversity Index (H) indicated highest value (2.413) during 1985-1986 and lowest value (1.265) during 2018-2019. The Pieolu's species evenness (J) varied between 0.438 and 0.812 with highest value during 1985-1986 and lowest value during 2018-2019, indicating that species diversity and their distribution have considerably been reduced in the Manoli Island over three decades. The decline of the most dominant species, Lesser Sand Plover Chadadrius mongolus was moderate while several others species declined dramatically. The absence of several species over time from the uninhabited island is a conservation concern. This study is the first of its kind done on an island in India for three decades that emphasises the importance of long-term monitoring of various wintering sites of CAF that will help in assessing the changes in the global population of these long-migratory shorebirds and guide to future conservation actions.
KEYWORDS
Central Asian Flyway, Conservation, Habitat Loss, Intertidal Zone, Population Monitoring
Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] Byju H , S Balachandran , S. Ravichandran , "Long-term Population Trends of Migratory Shorebirds- A Case Study from Manoli Island, the Gulf of Mannar Biosphere Reserve, India," Advances in Zoology and Botany, Vol. 11, No. 6, pp. 443 - 453, 2023. DOI: 10.13189/azb.2023.110605.
(b). APA Format:
Byju H , S Balachandran , S. Ravichandran (2023). Long-term Population Trends of Migratory Shorebirds- A Case Study from Manoli Island, the Gulf of Mannar Biosphere Reserve, India. Advances in Zoology and Botany, 11(6), 443 - 453. DOI: 10.13189/azb.2023.110605.