Status of water birds in Haripura-Baur Reservoir , western Terai-Arc landscape , Uttarakhand , India

We surveyed water birds in Haripura-Baur Reservoir using total count method between 2013 and 2015. A total of 65 species were recorded representing eight orders and 14 families. Numerically Anatidae was the dominant family followed by Ardeidae and Scolopacidae. Common Coot Fulica atra, Red-crested Pochard Netta rufina, Common Pochard Aythya ferina, Gadwall Anas strepera, and Tufted Pochard Aythya fuligula were dominant species in the reservoir. The Shannon diversity of water birds was more or less consistent over the years and ranged between 2.56 (2013–14) and 2.23 (2015–16). The reservoir supports water birds having declining population trends globally (41% of species), including three Vulnerable (Asian Woollyneck Ciconia episcopus, Lesser Adjutant Leptoptilos javanicus, and Sarus Crane Grus antigone and four Near Threatened species (Oriental Darter Anhinga melanogaster, Painted Stork Mycteria leucocephala, Black-necked Stork Ephippiorhynchus asiaticus, and River Lapwing Vanellus duvaucelii). Bird species belong to four feeding guilds with the domination of the carnivore group. The current information is expected to serve as preliminary database of water birds for further research and monitoring.


INTRODUCTION
Terai-Arc Landscape (henceforth TAL)-a green belt, runs along the foothills of the Himalaya from the river Bagmati in the east to the Yamuna in the west. It represents two distinct zones, i.e., Bhabar tract and the Terai plains of India (Rodgers & Panwar 1988). TAL is a mosaic of various habitats such as forests, grasslands, riverbeds, swamps, plantations, scrubland and wetlands that sustains birds representing Himalayan and Gangetic plain affinities (Rahmani et al. 1989;Pandey et al. 1994;Javed et al. 1999;Naoroji 1999;Dhakate et al. 2008).
The wetlands in the western part of TAL serve as an important habitat for resident and migratory birds (Dhakate et al. 2008;Bhattacharjee & Bargali 2013). Additionally, bird species categorized under the various categories of IUCN Red List of Threatened Species, viz., Darter Anhinga melanogaster, Painted Stork Mycteria leucocephala, Black-necked Stork Ephippiorhynchus asiaticus, Lesser Adjutant Leptostilos javanicus, Sarus Crane Grus antigone, and River Tern Sterna aurantia find home in these water bodies. Near Threatened migratory bird species such as Black-tailed Godwit Limosa limosa and Ferruginous Duck Aythya nyroca regularly winter in these wetlands (Bhattacharjee & Bargali 2013;Bhatt et al. 2014). Most importantly, the Bean Goose Anser fabalis, vagrant bird species which breed in the high Arctic and winter in temperate and sub-tropical regions (BirdLife International 2016) have been reported from these wetlands (Bhattacharjee 2013). The occurrence of these species highlight the significance of such wetlands for conservation of water birds, however, these water bodies do not have any legal conservation status and are basically managed for irrigation purposes. Furthermore, these wetlands are used for commercial fishing which not only reduces food availability to many native fish and bird species but is also a major cause of disturbance to the water birds.
Water birds assemblage in western TAL has been reported from Tumariya Reservoir (Bhattacharjee & Bargali 2013), Bheemgora barrage (Bhatt et al. 2014), Hathnikund barrage (Tak et al. 2010), and the water bodies of Corbett landscape (Dhakate et al. 2008). Information on the status of the water bird assemblage of Haripura-Baur Reservoir is not known and the present study is a pioneer attempt towards systematic data collection on water bird assemblage here. It is expected that the information will serve as a preliminary database of water birds for further research, monitoring and management.

Study area
Haripura-Baur Reservoir (HBR) (29.135 0 N & 79.294 0 E) are earthen embankment dams located approximately 15km from Bazpur in Udham Singh Nagar District of Uttarakhand ( Fig. 1; Image 1). HBR is a man-made wetland constructed in 1974 primarily for the purpose of storing water for irrigation purposes. Haripura having a maximum height of approximately 17m and length of 10km is built on Baur and Kakrala rivers, whereas, Baur with a maximum height of about 11m and length of 8km is built on Bhakhara River. Both reservoirs are adjacent to each other and spread over an area of 294.4km 2 . Considering the limited height and primary role of providing water for irrigation these dams are rarely filled with water to the maximum capacity leaving shallow water areas towards the margins. Mostly the reservoir is devoid of any vegetation; however, the shallow water level at the eastern, western and northern periphery of HBR support aquatic free floating, submerged and semisubmerged plants such as Ipomoea aquatica, Saccharum spontaneum, Typha sp., Polygonum barbatum, Vallisnaria spp., Hygrophila polysperma, Sagittaria sagittifolia, Phragmites karka, Azolla pinneta, Eichhornia crassipes, Nymphaea spp., Nymphoides cristata, and Stellaria media. The southern edge of these dams is earthen embankment with a motorable road. Some introduced fish fauna in the reservoir includes Catla catla (Catla), Labeo rohita (Rohu), Sperata seenghala, Hypophthalmichthys molitrix (Silver Carp), Cirrhinus mrigala (Nain), Channa marulius (Saur), C. striatus (Shaul), and Wallago attu (Lachi).

Methods
Information on water birds was collected by visiting the wetland fortnightly during November-February (winter season) between 2013-14 and 2015-16. Birds were counted by applying total count method following Koskimies & Vaisanen (1991). Since it was not possible to cover the entire reservoir from a single point, water birds were counted by selecting more than one point. Species were recorded along with their numbers between 07.00h and 12.00h. Field observation were not carried out during adverse environment condition. Identification of species was based on Grimmett et al. (1998). Conservation status and global population trend of water birds in HBR was determined from IUCN (2016).

Data analysis
Water bird community structure was determined through calculating various metrics such as Shannon's diversity (H), Margalef's richness (S), and evenness. Species richness represents totally unique species of water birds detected in all surveys. Shannon's diversity index describes diversity of species taking into account abundance of species. Evenness is an index of distribution of individuals among species. All the bird community indices were evaluated using Past 3.0 software (Hammer et al. 2017).
Maximum individuals of a bird species in a year were considered to determine the abundance of a species over a year. All the individuals of water birds sighted during various years were pooled to determine the abundance of bird species and birds were ranked into categories following Sultana & Khan (2000): Rare = 1-10 individuals; Common= 11-100 individuals; Abundant = 101-500 individuals; Very abundant = >500 individuals.
The mean rank abundance score for each species was calculated to assess the overall abundance in HBR. Birds were categorised into various feeding guilds following Ali (2002).

DISCUSSION
The wetlands in western TAL has been a regular winter abode for a large number of resident and migratory water birds (Dhakate et al. 2008;Bhattacharjee & Bargali 2013). HBR constructed primarily for the purpose of regulating water for irrigation purposes also supports water birds; however, there has been less focus on water birds visiting the reservoirs and on their conservation or management. The species recorded suggest that HBR support almost 50% of water birds species recorded from western TAL (Dhakate et al. 2008   & Bargali 2013). The occurrence of winter migrants and birds categorized under the IUCN Red List of Threatened Species signifies the importance of HBR as a foraging and resting habitat for migratory and resident water birds. HBR supported a consistent diversity of water birds over the study period. The diversity of water birds recorded during the present study might be due to availability of a wide spectrum of feeding resources in the study area in the form of crustaceans, invertebrates, emergent vegetation and plankton. Moreover, occurrence of fish species like Catla catla, Labeo rohita, Sperata seenghala, and Wallago attu in the reservoir also serve as important dietary resources for water birds, as also the surrounding agriculture fields that provide foraging grounds. Kloskokowski et al. (2010) suggested fish age and biomass, amphibian abundance, water transparency and emergent vegetation govern the richness of water birds. The domination of carnivore guild in the reservoir could be due to the high availability of fish fauna. The low abundance of water birds during 2014-15 could be related to low water levels and subsequent agriculture-based activities in non-submerged areas. This also supports the results of Bolduc & Aftan (2008), who has highlighted that the water bird abundance is controlled by water depth.

Total individuals Diversity Richness Evenness
Since the reservoir is managed by the irrigation 14164 Fishing in the reservoir post monsoon causes lots of disturbance to the water birds. Hence, we strongly recommend to allow only traditional fishing activities through proper inter-departmental cooperation and for developing a sound policy to regulate water for irrigation purposes, commercial fishing with an emphasis on the conservation of water birds. Aarif et al. (2017) highlighted that traditional fishing activities enhance water bird abundance and diversity. Considering the limited water bodies in western TAL, HBR plays a considerable role in providing the required habitat to migratory as well as resident water birds. It provides home to a high proportion of water birds having declining population trends. If managed properly it will not only provide crucial habitat to water birds but an opportunity for promoting eco-tourism by developing the site as a bird tourism destination.