Conservation significance of Changaram wetlands - a key wintering site for migratory shorebirds and other waterbirds in the western coast of Kerala, India

: Changaram wetland is an important stopover ground for migratory shorebirds, gulls, terns, and other waterbirds in the western coast of Kerala and it encompasses major habitats like exposed mudflats, mangrove fringes, and an agroecosystem. A total of 77 species of waterbirds (shorebirds, large wading birds, gulls, and terns) including long distance migrants, local migrants, and resident species were encountered in our survey carried out during 2018 and 2019. Ten out of these 77 species fall under threatened category in the IUCN Red List and hence the Changaram wetlands demand immediate attention from the conservation perspective. Considering tremendous anthropogenic pressures faced by these wetlands, and the decline in the abundance of waterbirds, a regular system for monitoring the bird population and the wetlands must be deployed for the conservation of the ecosystem and of the birds.


INTRODUCTION
Wetlands make up 5─8% of the earth's surface. According to the national wetland inventory and assessment prepared by the Indian Space Research Organization (ISRO), wetlands cover 1,52,600 km 2 (4.63%) of the total land area of India and support onefifth of the biodiversity (Bassi et al. 2014). Of the total area Inland, natural wetlands make up 43.4% whereas coastal natural wetlands make up 24.3% (SAC 2011;Panigrahy et al. 2012). In the last three centuries, global wetland loss is estimated to be 54-57%, but it might be as high as 87% (Davidson 2014). Scientific estimates show that 64% of the world's wetlands have disappeared since 1900 (Ramsar Fact Sheet 2014) due to human activity & urbanization, which has affected ecosystem health & quality (Ballut-Dajud et al. 2022). It is significant to mention the recent notification (in 2022) of the Government of India to designate more sites into Ramsar wetlands and the total number of Ramsar sites stands at 75, covering an area of about 13,26,677 ha (Government of India website 2022). Over the past 20 years, tidal wetlands have lost 4,000 km 2 of their land area, but ecosystem restoration and natural processes are helping to reverse the trend (Murray et al. 2022).
Wetlands provides an excellent habitat for migratory waterbirds and shorebirds, for feeding, nesting, rearing young ones, and as wintering grounds/stopover grounds. The degradation of wetland habitat may cause the water-table to drop, the food chain to get disrupted, eventually migratory bird populations to decline, and the nutrient cycle to slow down, all of which are detrimental to the environment, ecosystem, and human beings (Kumar & Kanaujia 2014). Wetlands in Kerala are under threat due to accelerated developmental activities and indiscriminate land & water use. However, no reports on the precise rate of wetlands destruction in Kerala is available, other than some reports on its qualitative degradation (Kokkal et al. 2008). The major issues leading to wetland degradation are pollution, eutrophication, encroachment, reclamation, mining, and biodiversity loss (Kokkal et al. 2008;Ballut-Dajud et al. 2022). The habitat destruction may lead to a decline in the abundance of shorebirds, as they are the top level predators, and hence they can be considered as bioindicators of ecosystem health. Thus, understanding the structure of bird community in a habitat is essential to identify the local landscapes for the conservation of avifauna and their ecosystem (Kattan & Franco 2004).
Changaram wetland is an important stopover ground for migratory shorebirds, gulls, terns, and other waterbirds in the west coast of Kerala and it encompasses major habitats like exposed mudflats, mangrove fringes, and an agroecosystem. Hence it draws the attention of conservation biologists to formulate strategies for the protection of this significant ecosystem and its components. Being the ecological indicators, the present study of avifaunal observations from Changaram wetland will serve as baseline data for conservation measures to be taken up in this key wintering site of long-distance migratory shorebirds and other waterbirds in the near future.

Study Site
Changaram (9.797438°N, 76.28876°E) (Image 1), spreads across 145 acres (57.87 ha) in the Kodamthuruth panchayats of Cherthala Taluk in Alappuzha District, western coast of Kerala. It is a waterlogged, palm fringed village with a narrow strip of land, on the coastal belt, with the Arabian Sea on the west, and Thazhappu Kayal (backwaters) on the east, Ezhupunna wetland on the north, and Pallithodu wetland on the south. Interconnected extensive paddy fields are seen in Changaram wetlands where Pokkali system of agriculturea single crop of rice is cultivated on mounds during the low saline phase of the production cycle (June─mid October), followed by shrimp farming (Penaeus monodon, Penaeus semisulcatus) during the high saline phase (November─April) is practiced (Chandramohanan & Mohanan 2011). Changaram wetland has no direct connection to the estuary so it is barely affected by tidal activity. During shrimp farming, bunds are constructed, and water is pumped into it. After the shrimp culture, the water is drained out exposing the mudflats, which offer potential foraging ground for hundreds of wintering and resident waterbirds, particularly shorebirds. It also serves as an ideal breeding ground for several waterbird species. A short stretch of mangrove forests (major J TT species-Avicennia officinalis, Rhizophora mucronata, Excoecaria agallocha, and Bruguiera cylindrica) of about 0.607 ha area extends on the edges of the Changaram wetland. The wetland is flanked by coconut trees and populated areas except from intermittent patches of these mangroves.

Methods
Waterbirds survey (including shorebirds, large wading birds, gulls, and terns) was carried out once a month (0700─1100 h) between 2018 and 2019. Observations were made using binoculars (10 x 50 Nikon) and a 4k series Nikon Coolpix p1000 camera. Data was collected following direct count (Howes & Bakewell 1989) and block count methods (Jadhav & Parasharya Image 1. Map showing the study area of Changaram wetlands. A total of four scanning points (two each at agroecosystem and mangroves) were selected to carried out the survey during the study period.

J TT
2004; Urfi 2004). Shorebirds were encountered at four scanning points (Image 1) in both agro-ecosystem and mangroves which covered the whole area. The observations recorded while moving from one scanning point to another were entered as incidental records.
The status of waterbirds based on the frequency of sightings were categorized into Common (seen during most of the visits), Uncommon (seen less than five times), and Rare (seen once or twice). Migratory statuses of waterbirds were classified into Resident but not breeding (R/B-Resident but not breeding, which means, those birds are breeding at adjoining areas of the study site), Local Migrant (LM-Locally migrant, which means birds are breeding within the country), Breeding (Br-Breeding, means commonly or uncommonly breeding in the study site) and Winter Visitor (WV-Winter Visitor, birds visiting from another region or other countries) (Mc Kinnon & Philips 1993;Aarif et al. 2017a). The species-level identification was done with the help of a field guide (Grimmet et al. 1999) and based on our field experience.

RESULTS AND DISCUSSION
The total count of waterbirds during the year 2018 was 20,100 individuals and that of the year 2019 was 18,600 individuals. 77 species were identified from this fragile ecosystem. Among the 77 species recorded, 38 species of shorebirds, 23 species of other waterbirds (large wading birds), five species of gulls, and 11 species of terns were also recorded from the study area (Table  1-3). Among the shorebirds listed, 31 species were winter visitors, two species-Kentish Plover Charadrius alexandrinus and Great Thick-knee Escacus recurvirostris were local migrants, three species were resident but not breeding, and the two remaining species were breeding. Further, 16 species of shorebirds were common, three species were uncommon, and the remaining 19 species were classified as rare (Table 1). The most dominant species among the observed shorebirds was the Black-tailed Godwit Limosa limosa (Peak count at one time-2,534 in April) followed by Wood Sandpiper Tringa glareola (Peak count at one time-1,123 in May).
Among the 23 species of waterbirds listed, 18 species were most common, three species were uncommon, and two species were rare (  (Aarif et al. 2011.
Most of the shorebird species were documented during their northward return migratory season, i.e., March, April, and May, while some other shorebird

J TT
species were found over-summer in small numbers during June and July in the study area. The over-summering shorebirds were Black-tailed Godwit, Common Sandpiper Actitis hypoleucos, Wood Sandpiper, Marsh Sandpiper Tringa stagnatilis, and Pacific Golden Plover Pluvialis fulva. Similarly, several over-summering species have been reported from KVCR and it was pointed out that the over-summering birds were either juveniles or adults which were physically or sexually unfit (Aarif et al. 2017a(Aarif et al. , 2020. Hence it can be elucidated that the oversummering shorebirds are provided with food resources and shelter in the habitat, throughout the year.

CONSERVATION ISSUES
Many long-distance migrant shorebirds are well known to be highly reliant on a series of key stop-over sites between wintering and breeding grounds (Boere et al. 2006). As it is home to several important long-distance migrant species, the link between this coastal wetland and many other major shorebird habitats within India and other countries along the Central Asian Flyway must be unraveled through regular and systematic monitoring.
Thousands of migratory waterbirds use the western coast of India as a refuge during the winter, yet there are only a few systematic studies that are reported from KVCR in Kerala State (Aarif et al. , 2020(Aarif et al. , 2021aAthira et al. 2022;Rashiba et al. 2022) and Sindhudurg District of Maharashtra State (Rao et al. 2022), that provide data on continuous population monitoring. The ability of the migratory shorebirds to live in varied coastal environments makes them a global indicator species for any changes in habitat (Piersma & Lindstrom 2004).
For long-distance migrant shorebirds, the ecological quality of wintering grounds appears to be of key importance (Aarif et al. , 2021a and in the west coast, this quality is greatly affected by environmental  Common (seen on most of the visits) | Uncommon (seen less than five times) | Rare (seen once or twice).

Image 2. Mixed flocks (Lesser Sand Plover and Curlew Sandpiper) of shorebirds from Changaram wetland. © S. Abhijith
Image 3. Asian Dowitcher (rarely seen ) from Changaram wetland. © S. Abhijith J TT threats due to tremendous anthropogenic pressures-e.g., habitat destruction and organic solid waste dumping (Aarif et al. , 2020(Aarif et al. , 2021a. Therefore, it is imperative that continuous monitoring throughout the wintering season should be undertaken in this wetland too. Changaram wetland is under tremendous anthropogenic pressures like plastic litter dumping, habitat incursion leading to alterations, also left-over nettings & plastic traps from shrimp farming, which may lead to bird injury Aarif et al. 2021b) and thus the reduction of waterbirds. While the mudflats exposed after shrimp farming serve as ideal foraging grounds for wading birds, the left-over synthetic fiber threads pose a constant danger to waterfowls, as reported from KVCR (Aarif et al. 2011. Proactive steps, to alleviate these man-made impacts, like timely removal of discarded fishing accessories and spurious remains from wetlands may abate migratory bird injuries (Aarif et al. 2021b). Other threats include electrocution, feral predators like cats and stray dogs, as reported elsewhere (Blancher 2013).

CONCLUSION
To sum up, this study may be a trailblazer as there is no other systematic investigation reported from Changaram wetland and adjoining areas till date. This could serve as a baseline information in assessing population trends, dynamics, and habitat use of regular winter migrant shorebirds and other waterbirds from the area. Regular long-term monitoring and assessment should be conducted in future so as to establish the importance of this wetland in the world avian map. Further, the local community inhabiting the area may be given awareness of the importance and need for maintaining and conserving a healthy ecosystem. Nevertheless, this study provides the first comprehensive baseline data of selected shorebirds and other waterbirds from Changaram wetland and would be extremely helpful for future research in this site and for upholding the need of designating this as an area of conservation importance.

www.threatenedtaxa.org
The Journal of Threatened Taxa (JoTT) is dedicated to building evidence for conservation globally by publishing peer-reviewed articles online every month at a reasonably rapid rate at www.threatenedtaxa.org. All articles published in JoTT are registered under Creative Commons Attribution 4.0 International License unless otherwise mentioned. JoTT allows allows unrestricted use, reproduction, and distribution of articles in any medium by providing adequate credit to the author(s) and the source of publication.