Abstract
Urban wetlands are increasingly threatened by pollution, habitat modification, and unregulated human activities, despite supporting significant avifaunal diversity. This study assessed the waterbird assemblage structure and anthropogenic pressures in Sengulam Lake, an urban wetland in Coimbatore within the Noyyal River basin, south India (March 2025 to February 2026), using vantage point count method. A total of 151 avian species belonging to 19 orders and 56 families were recorded. Passeriformes was the dominant order (57 species), while Ardeidae was the dominant family (11 species). The resident species predominated (110 species), followed by winter visitors (36 species) and local migrants (5 species). The assemblage was largely composed of Least Concern species (148 species), with two Near Threatened species - Indian Roller Coracias benghalensis and Asian Woollyneck Ciconia episcopus, and one Vulnerable species River Tern Sterna aurantia. Carnivorous and omnivorous birds formed the dominant feeding guilds throughout the study period. Species richness (119 species) and abundance (1676 individuals) were the highest in December. Shannon diversity remained consistently high (3.16–3.80), with low Simpson’s dominance values (0.038–0.090), indicating the absence of strong dominance by any single species. Temporal beta diversity (βSOR = 0.634) was mainly driven by species turnover (βSIM = 0.476). Major threats were sewage inflow, solid waste dumping, water hyacinth invasion, recreational disturbance, stray dogs, and habitat alteration. These pressures affected multiple avifaunal guilds through habitat degradation, altered foraging behaviour, and displacement. The study highlights the need for sewage management, invasive species control, and shoreline protection, thereby emphasising the conservation importance of Sengulam-Lake.
Keywords
References
- Adhurya, S., Das, S., & Ray, S. (2018). Guanotrophication by waterbirds in freshwater lakes: a review on ecosystem perspective. In Springer, Singapore (pp. 253–269). https://doi.org/10.1007/978-981-15-0422-8_22 [Google Scholar]
- Ali, S., & Ripley, S. D. (1987). Compact handbook of the birds of India and Pakistan. Oxford University Press. [Google Scholar]
- Aronson, M., La Sorte, F. A., Nilon, C. H., Katti, M., Goddard, M. A., Lepczyk, C. A., Warren, P. S., Williams, N. S. G., Cilliers, S., Clarkson, B., Dobbs, C., Dolan, R., Hedblom, M., Klotz, S., Kooijmans, J. L., Kühn, I., MacGregor-Fors, I., McDonnell, M., Mörtberg, U., Pyšek, P., et al. (2014). A global analysis of the impacts of urbanization on bird and plant diversity reveals key anthropogenic drivers. Proceedings of the Royal Society B: Biological Sciences, 281(1780), 20133330. https://doi.org/10.1098/rspb.2013.3330 [Google Scholar]
- Balfors, B., Azcarate, J., Mörtberg, U., Karlson, M., & Gordon, S. (2016). Impacts of urban development on biodiversity and ecosystem services. In D. Geneletti (Ed.), Handbook on biodiversity and ecosystem services in impact assessment (pp. 167–194). Edward Elgar Publishing. [Google Scholar]
- Baselga, A. (2010). Partitioning the turnover and nestedness components of beta diversity. Global Ecology and Biogeography, 19(1), 134–143. https://doi.org/10.1111/j.1466-8238.2009.00490.x [Google Scholar]
- Battin, J. (2004). When good animals love bad habitats: ecological traps and the conservation of animal populations. Conservation Biology, 18, 1482–1491. https://doi.org/10.1111/j.1523-1739.2004.00417.x [Google Scholar]
- Bibby, C. J., Burgess, N. D., Hill, D. A., & Mustoe, S. (2000). Bird census techniques (2nd ed.). Academic Press. [Google Scholar]
- Blumstein, D. T., Fernández-Juricic, E., Zollner, P. A., & Garity, S. C. (2005). Inter-specific variation in avian responses to human disturbance. Journal of Applied Ecology, 42, 943–953. https://doi.org/10.1111/j.1365-2664.2005.01071.x [Google Scholar]
- Bolpagni, R. (2021). Towards global dominance of invasive alien plants in freshwater ecosystems: the dawn of the Exocene? Hydrobiologia, 848, 1–21. https://doi.org/10.1007/s10750-020-04490-w [Google Scholar]
- Burger, J., & Gochfeld, M. (2004). Marine birds as sentinels of environmental pollution. EcoHealth, 1, 263–274. https://doi.org/10.1007/s10393-004-0096-4 [Google Scholar]
- Byju, H., Maitreyi, H., & Ravichandran, S. (2025a). Temporal dynamics of shorebird assemblages in Valinokkam Lagoon, southeast India: a new wintering site along the Central Asian Flyway. Ornis Hungarica, 33, 22–42. https://doi.org/10.2478/orhu-2025-0018 [Google Scholar]
- Byju, H., Maitreyi, H., Aarif, K. M., & Raveendran, N. (2025c). Disappearing colonies: temporal decline in abundance and nesting of waterbirds in a key Indian wetland. Wetlands Ecology and Management, 33(4), 47. https://doi.org/10.1007/s11273-025-10067-y [Google Scholar]
- Byju, H., Maitreyi, H., Raveendran, N., & Vijayan, R. (2024b). Avifaunal diversity assessment and conservation significance of Therthangal Bird Sanctuary, Ramanathapuram, Tamil Nadu: insights about breeding waterbirds. Journal of Threatened Taxa, 16(9), 25802–25815. https://doi.org/10.11609/jott.8999.16.9.25802-25815 [Google Scholar]
- Byju, H., Maitreyi, H., Raveendran, N., Ravichandran, S., & Vijayan, R. (2025b). Avifaunal diversity and conservation status of waterbirds in Pillaimadam Lagoon, Palk Bay, India. Journal of Threatened Taxa, 17(4), 26789–26802. https://doi.org/10.11609/jott.9432.17.4.26789-26802 [Google Scholar]
- Byju, H., Maitreyi, H., Ravichandran, S., & Raveendran, N. (2024a). Avifaunal diversity and conservation significance of coastal ecosystems on Rameswaram Island, Tamil Nadu, India. Journal of Threatened Taxa, 16, 26198–26212. https://doi.org/10.11609/jott.9248.16.12.26198-26212 [Google Scholar]
- Byju, H., Raveendran, N., Ravichandran, S., & Vijayan, R. (2023). A checklist of the avifauna of Samanatham tank, Madurai, Tamil Nadu, India. Journal of Threatened Taxa, 15(9), 23857–23869. https://doi.org/10.11609/jott.8419.15.9.23857-23869 [Google Scholar]
- Byju, H., Raveendran, N., Ravichandran, S., Kishore, R., & Vijayan, R. (2024c). An annotated avifaunal checklist of Sikkal Tank, Ramanathapuram, Tamil Nadu, India with notes on the site's importance on waterbird conservation. Advances in Zoology and Botany, 12(2), 115–126. https://doi.org/10.13189/azb.2024.12020 [Google Scholar]
- Byju, H., Rubeena, K. A., Shifa, C. T., Athira, T. R., Jishnu, K., Singh, J., Sohil, A., Kushwah, S., Kumar, A., Anand, J., Rajaneesh, K.M., Manokaran, S., Gijjappu, R.D., Reshi, O.R., Ilyas, O., Sharma, N., Junaina, K.K., Raveendran, N., Mumthaz, T.M.V., Nasser, M., Muzaffar S.B., Nefla, A., Rahman, S.M., & Aarif K.M. (2024d). Transitioning wintering shorebirds to agroecosystem: a thorough evaluation of habitat selection and conservation concern. Diversity, 16, 23. https://doi.org/10.3390/d16010023 [Google Scholar]
- Chace, J., & Walsh, J. (2006). Urban effects on native avifauna: a review. Landscape and Urban Planning, 74, 46–69. https://doi.org/10.1016/j.landurbplan.2004.08.007 [Google Scholar]
- Chao, A. (1984). Nonparametric estimation of the number of classes in a population. Scandinavian Journal of Statistics, 265–270. [Google Scholar]
- Clergeau, P., Croci, S., Jokimäki, J., et al. (2006). Avifauna homogenization by urbanization: analysis at different European latitudes. Biological Conservation, 127(3), 336–344. https://doi.org/10.1016/j.biocon.2005.06.035 [Google Scholar]
- Gill, J. A., et al. (2001). Why behavioural responses may not reflect the population consequences of human disturbance. Biological Conservation, 97(2), 265–268. https://doi.org/10.1016/S0006-3207(00)00002-1 [Google Scholar]
- Grimmett, R., Inskipp, C., & Inskipp, T. (2011). Birds of the Indian Subcontinent (2nd ed.). Oxford University Press. [Google Scholar]
- Guptha, M. B., Vijayan, L., Sandaliyan, S., & Sridharan, N. (2011). Status of wetlands and wetland birds in Coimbatore, Trichy, Perambalore and Thiruvarur districts in Tamil Nadu, India. World Journal of Zoology, 6(2), 154–158. [Google Scholar]
- ICID. (2022). International Commission on Irrigation & Drainage- Noyyal River System Tanks. https://icid-ciid.org/award/his_details/225 [Google Scholar]
- IUCN. (2026). The IUCN Red List of Threatened Species. Version 2025-2. https://www.iucnredlist.org [Google Scholar]
- Jena, D., Daoun, A., Mishra, P., Parida, N. R., Dash, S., Jena, S. K., & Das, V. G. S. (2025). Impact of wetland degradation on biodiversity and livelihoods in Mangalajodi: An assessment using factor analysis and discriminant analysis. Journal of Environmental Biology, 46(5), 635–644. https://doi.org/10.22438/jeb/46/5/MRN-5667 [Google Scholar]
- Kadlec, R. H., & Wallace, S. (2009). Treatment wetlands (2nd ed.). Taylor & Francis. [Google Scholar]
- Kati, V., & Sekercioglu, C. H. (2006). Diversity, ecological structure, and conservation of the landbird community of a Greek reserve. Diversity and Distributions, 12, 620–629. https://doi.org/10.1111/j.1366-9516.2006.00288.x [Google Scholar]
- Keddy, P. A. (2010). Wetland ecology: principles and conservation. Cambridge University Press. [Google Scholar]
- Kenmegne, R. L. T., Hemchi, H. M., & Bissonnette, J. F. (2025). How to integrate wetlands in urban planning to achieve greater resilience? The case of Douala IV urban municipality (Cameroon). Journal of Urban Management, 15(2), 964–977. https://doi.org/10.1016/j.jum.2025.10.005 [Google Scholar]
- Kumar, C. N., Revathi, R., Jaisankar, I., Baranidharan, K., & Rasu, P. D. (2014). Avifaunal diversity of Ukkadam Lake in Coimbatore District of Tamil Nadu, India. Indian Forester, 140(10), 982–987. [Google Scholar]
- Lilleyman, A., Franklin, D. C., Szabo, J. K., & Lawes, M. J. (2016). Behavioural responses of migratory shorebirds to disturbance at a high-tide roost. Emu, 116(2), 111–118. https://doi.org/10.1071/MU14070 [Google Scholar]
- Longcore, T., & Rich, C. (2004). Ecological light pollution. Frontiers in Ecology and the Environment, 2, 191–198. https://doi.org/10.1890/1540-9295(2004)002[0191:ELP]2.0.CO;2 [Google Scholar]
- Mathibalan, T., Byju, H., Maitreyi, H., Raveendran, N., Sheela, S., & Anand, J. (2026). Diversity and composition of avian populations in Sivagalai Wetland, Thoothukudi, India. Journal of Experimental Zoology India, 29, 965–974. https://doi.org/10.51470/jez.2026.29.1.965 [Google Scholar]
- McKinney, M. L. (2006). Urbanization as a major cause of biotic homogenization. Biological Conservation, 127, 247–260. https://doi.org/10.1016/j.biocon.2005.09.005 [Google Scholar]
- Mitsch, W. J., & Gosselink, J. G. (2015). Wetlands (5th ed.). John Wiley & Sons. [Google Scholar]
- Naveen Kumar, R., Muraleedharan, R., Kalyani, R., Maitreyi, H., & Byju, H. (2025). Avifaunal diversity of Chinnavedampatti Lake: an urban wetland in Coimbatore, Tamil Nadu, India. Journal of Experimental Zoology India, 28, 1383–1395. https://doi.org/10.51470/jez.2025.28.2.1383 [Google Scholar]
- Nayak, A., & Sasmal, S. (2022). Post-monsoon bird assemblages in rural and riverine environments of Northern Howrah, West Bengal, India: a spatio-temporal approach. Notulae Scientia Biologicae, 14(1), 11078. https://doi.org/10.15835/nsb14111078 [Google Scholar]
- Nguyen, H. V., Nguyen, N. T., & Phan, V. H. (2023). Urban expansion in Ho Chi Minh City detected from Landsat satellite images. In Springer Nature (pp. 1710–1718). https://doi.org/10.1007/978-981-99-7434-4_184 [Google Scholar]
- Ogden, J. C., Baldwin, J. D., Bass, O. L., Browder, J. A., Cook, M. I., Frederick, P. C., Frezza, P. E., Galvez, R. A., Hodgson, A. B., Meyer, K. D., Oberhofer, L. D., Paul, A. F., & Towles, T. (2014). Waterbirds as indicators of ecosystem health in the coastal marine habitats of southern Florida: selection and justification for a suite of indicator species. Ecological Indicators, 44, 148–163. https://doi.org/10.1016/j.ecolind.2014.03.007 [Google Scholar]
- Oksanen, J., Simpson, G. L., Blanchet, F. G., Kindt, R., et al. (2024). vegan: Community Ecology Package (R package version 2.6-10). https://CRAN.R-project.org/package=vegan [Google Scholar]
- Parameswaran, G., Sivashankar, R., & Vridhi, R. (2023). Rapid decline of waterbirds in urban wetlands: a case study from Perur, Sundakamuthur Lake, Coimbatore, Tamil Nadu, India. Indian Birds, 19(3), 67–74. [Google Scholar]
- Pielou, E. C. (1966). The measurement of diversity in different types of biological collections. Journal of Theoretical Biology, 13, 131–144. https://doi.org/10.1016/0022-5193(66)90013-0 [Google Scholar]
- R Core Team. (2026). R: a language and environment for statistical computing. R Foundation for Statistical Computing. [Google Scholar]
- Raj, P. P. N., Ranjini, J., Dhanya, R., Subramaniyan, J., Azeez, P. A., & Bhupathy, S. (2010). Consolidated checklist of birds in the Pallikaranai Wetlands, Chennai, India. Journal of Threatened Taxa, 2(8), 1114–1118. https://doi.org/10.11609/JoTT.o2220.1114-8 [Google Scholar]
- Ramsar Convention Secretariat. (2018). Global wetland outlook: state of the world's wetlands and their services to people. Ramsar Convention Secretariat. [Google Scholar]
- Reginald, L. R., Mahendran, C., Suresh Kumar, S., & Pramod, P. (2007). Birds of Singanallur Lake, Coimbatore, Tamil Nadu. Zoos' Print Journal, 22(12), 2944–2948. [Google Scholar]
- Sauer, J., & Chang, H. (2023). People, place, and planet: global review of use-inspired research on water-related ecosystem services in urban wetlands. Cambridge Prisms: Water, 2, e1. https://doi.org/10.1017/wat.2023.19 [Google Scholar]
- Seto, K. C., Güneralp, B., & Hutyra, L. R. (2012). Global forecasts of urban expansion to 2030 and direct impacts on biodiversity and carbon pools. Proceedings of the National Academy of Sciences, 109(40), 16083–16088. https://doi.org/10.1073/pnas.1211658109 [Google Scholar]
- Shannon, C. E., & Weaver, W. (1949). The mathematical theory of communication. University of Illinois Press. [Google Scholar]
- Singh, R., & Bhatnagar, M. (2012). Urban lakes and wetlands: opportunities and challenges in Indian cities—case study of Delhi. Proceedings of the 12th World Wide Workshop for Young Environmental Scientists (WWW-YES-2012). [Google Scholar]
- Sundar, K. S. G. (2006). Flock size, density and habitat selection of four large waterbirds species in an agricultural landscape in Uttar Pradesh, India. Waterbirds, 29(3), 365–374. [Google Scholar]
- Turčoková Rubáčová, L., Melišková, M., & Balážová, M. (2016). Nest site location and breeding success of Common Kingfisher (Alcedo atthis) in the Danube river system. Folia Oecologica, 43, 74–82. [Google Scholar]
- United Nations Department of Economic and Social Affairs. (2018). World urbanization prospects: the 2018 revision. United Nations. [Google Scholar]
- Urfi, A. J. (2003). The birds of Okhla barrage bird sanctuary, Delhi, India. Forktail, 19, 39–50. [Google Scholar]
- Vadrevu, K. P., Gutman, G., Tsuneo, M., & Justice, C. (2023). Land use changes, degradation, and impact on ecosystem services in Asia and Southeast Asia. Land Degradation & Development, 35(3), 919–922. https://doi.org/10.1002/ldr.4971 [Google Scholar]
- Villamagna, A. M., & Murphy, B. R. (2010). Ecological and socio-economic impacts of water hyacinth. Freshwater Biology, 55, 282–298. https://doi.org/10.1111/j.1365-2427.2009.02294.x [Google Scholar]
- Weston, M. A., & Stankowich, T. (2014). Dogs as agents of disturbance. In M. E. Gompper (Ed.), Free-ranging dogs and wildlife conservation (pp. 94–116). Oxford University Press. [Google Scholar]
- Weston, M. A., McLeod, E. M., Blumstein, D. T., & Guay, P. J. (2012). A review of flight-initiation distances and their application to managing disturbance to Australian birds. Emu, 112(4), 269–286. https://doi.org/10.1071/MU12026 [Google Scholar]
- Xu, T., Weng, B., Yan, D., Wang, K., Li, X., Bi, W., et al. (2019). Wetlands of international importance: Status, threats, and future protection. International Journal of Environmental Research and Public Health, 16(10), 1818. https://doi.org/10.3390/ijerph16101818 [Google Scholar]

