River Tern Research Articles

<b>Status and conservation issues of wetland birds in Komaranahalli Lake, Davanagere District, Karnataka, India</b>

This study was carried out to assess the status and conservation issues of migratory water birds in Komaranahalli Kere, a lake in Malebennur, Harihar Taluk, Davanagere District from November 2012 to October 2013. The dominant family was Ardeidae represented by 10 species, followed by the Scolopacidae with seven species. The families with lowest representations of one species were Podicipididae, Anhingidae, Rostratulidae and Recurvirostridae. The study revealed that the lake harbors many resident and a few migratory bird species. Among the species recorded five species namely the Black-headed Ibis Threskiornis melanocephalus, Oriental Darter Anhinga melanogaster, Black-tailed Godwit Limosa limosa, Painted Stork Mycteria leucocephala and River Tern Sterna aurantia are Near Threatened. The present study location is also facing tremendous conservation challenges by the impact of anthropogenic alteration of the habitats in and around the lake. Though the lake is highly disturbed, it still provides some potential habitats for a few migratory and several resident water bird species.

Occurrence of Indian Skimmer Rynchops albicollis eggs in River Tern Sterna aurantia nests

ABSTRACTCapsule: We report the first description of interspecific nest parasitism by the Indian Skimmer Rynchops albicollis. The incidence was low; only 2 out of 61 River Tern Sterna aurantia nests contained Indian Skimmer eggs.

Effectiveness of direct payments to increase reproductive success of sandbar-nesting river birds in Cambodia

SummaryDirect payments to communities or individuals have gained traction as a tool for species conservation; however, few studies have evaluated their effectiveness. From 2010 to 2014, we monitored nests and implemented a direct payment nest protection programme for six sandbar-nesting bird species on the Mekong River, Cambodia, and tested if nest protection improved reproductive success. Nests were guarded by community members; additionally, exclosures were used to protect nests of River Tern Sterna aurantia, the species of highest conservation concern. We investigated factors affecting nest and chick survival, and probability of nest failure due to egg harvest or predation. Nesting later in the season generally resulted in lower nest and chick survival. Nest protection improved survival rates of River Tern nests and chicks, and Small Pratincole Glareola lactea nests. River Tern nest success was 60% for exclosed (and guarded) nests, 29% for guarded (but unexclosed) nests, and 5% for unprotected nests. River Tern fledging success was 82% for exclosed chicks, 40% for chicks that were guarded only, and 2% for unprotected chicks. Small Pratincole nest success was 21% for guarded and 6% for unguarded nests. Egg harvest by humans was lower among protected nests and declined during the study. Nest predation by animals increased during the study despite nest guarding; however, predator exclosures effectively protected nests and chicks. Additional predator control measures could further improve reproductive success of sandbar-nesting birds. Overall, nest protection involving direct payments was highly effective, but required diligent use of nest exclosures, frequent monitoring, and strong community relationships.

Wetland Bird Assemblage in Rural Ponds of Kurukshetra, India

Abstract. Small sized, man-made, perennial and primarily rain-fed ponds occur widely in the rural landscape of India. These wetlands provide suitable habitats and food resources for a wide variety of resident and migratory wetland birds. Wetland birds in six rural ponds of Kurukshetra District, Haryana, in northern India were surveyed from April 2011 to May 2014 to determine status. Point counts and direct observations were used to record bird species. Sixty-nine species of wetland birds belonging to 47 genera and 20 families were identified. Family Anatidae dominated the avifauna with 20% (n = 14) of the species found. Of the species documented, 54% (n = 37) were winter migrants, 7% (n = 5) were summer migrants and 39% (n = 27) were residents. Among recorded species, Darter (Anhinga melanogaster), Painted Stork (Mycteria leucocephala), Oriental White Ibis (Threskiornis melanocephalus) and River Tern (Sterna aurantia) are considered as near threatened; Comb Duck (Sarkidiornis melanotos), Brahminy Kite (Ha...

Analysis of wetland Birds as seen in Yamuna river at Okhla (Delhi), Faridabad and Palwal Districts in Haryana, India

The present studies were done during 2008-11 for the observations of wetland birds in River Yamuna at Okhla (Delhi), Faridabad and Palwal districts in Haryana. Visits were made in an irregular manner. In all 2 visits were made at Faridabad; village Chandhat nearby Palwal and at Hodal nearby village Kulena. It is pertinent to mention that few visits were made in winter season at Okhla barrage in New Delhi. In all, 60 species were recorded belonging to 8 orders and 14 families. Out of these 60 species of wetland birds, 35 were winter migratory, 11 local migratory and 11 species of birds were resident. The specific wetland birds specific to Yamuna River between “Delhi-Faridabad-Palwal” segments include Ferruginous Pochard Aythya nyroca, Black-headed Gull Larus ridibundus, Greater Scaup Aythya marila, River Tern Sterna aurantia and Pallas Gull Larus ichthyaetus. Other popular wetland birds include, amongst others, Mallard Anas platyrhynchos, Northern Pintail Anas acuta, Northern Shoveller Anas clypeata, Red-crested Pochard Rhodonessa rufina, Common Pochard Aythya ferina, Tufted Pochard Aythya fuligula, Bar-headed Goose Anser indicus, Greylag Goose Anser anser, Brahminy Shelduck Tadorna ferruginea, Gadwall Anas strepera, Eurasian Wigeon Anas penelope, White-tailed Lapwing Vanellus leucurus, Ruff Philomachus pugnax, Common Greenshank Tringa nebularia, Pallas Gull Larus ichthyaetus, Painted Stork Mycteria leucocephala, Open-billed Stork Anastomus oscitans, White-necked Stork Ciconia episcopus, Eurasian Spoonbill Platalea leucorodia, Black tailed Godwit Limosa limosa, Wood Sandpiper Tringa glareola, Little Stint Calidris minuta, Common Redshank Tringa totanus, Spotted Redshank Tringa erythropus and Pied Avocet Recurivirostra avosetta.Black-headed Gulls were seen in thousands followed by Greylag Goose Anser anser, Northern Shoveller, Northern Pintail etc. Minimum number noticed were those of Greater Scaup, Ferruginous Pochards etc. Resident wetland birds include Little Cormorants Phalacrocorax niger, Median Cormorants Phalacrocorax fuscicollis, Large Cormorants Phalacrocorax carbo , Pond Herons Ardeola grayii, Night Herons Nycticorax nycticorax, Black winged Stilts Himantopus himantopus, Common Moorhens Gallinula chloropus, Bronze-winged Jacana Metopidius indicus, Red-wattled Lapwing Vanellus indicus, Grey Herons Ardea cinerea, large Egrets Ardea alba and Median Egrets Mesophoyx intermedia. However, Grey Herons were seen only in 2-3 numbers. It seems that most of the popular migratory birds, perhaps, prefer Jheels, Lakes, Barrages compared to Yamuna river stream. Birds in Yamuna are not continuous in their availability. Rather birds are encountered at specific spots only in a given segment. Painted Storks were seen in 1or 2 and that too in the vicinity of Yamuna region rather than its stream of water. However, birds were seen in innumerous numbers at Okhla Barrage in Yamuna River nearby Delhi.

Mesohabitat use by brown trout (Salmo trutta) in a small groundwater‐dominated stream

ABSTRACTGroundwater‐dominated streams have particular flow regimes that commonly support populations of trout. Meso‐ and micro‐habitat surveys were carried out on a reach of the river Tern that drains a Triassic sandstone aquifer in the English West Midlands, to investigate brown trout (Salmo trutta) habitat use with varying flows. Mesohabitats were mapped over a range of summer and autumn flows and coupled with direct underwater observation (snorkelling) of fish locations together with point measurements of velocity and depth. The number of habitat types recorded was low and dominated by glides, runs, and backwaters. Brown trout showed a strong association with glides and runs with adults being more associated with runs and parr with glides. General habitat use curves showed brown trout to favour depths between 0.30 and 0.40 m and velocities below 0.40 m s−1. A clear preference was shown for sand and gravel bed materials. However, the differentiation of hydraulic habitats was weak and there was no trend in mesohabitats or change in trout use of mesohabitats with discharge. The study raises limitations of the mesohabitat survey approach when linking fish ecology, flow and physical habitat in small streams with low flow variability and low habitat diversity. In these situations, other factors (especially cover features) appear to strongly influence brown trout distribution. Copyright © 2010 John Wiley & Sons, Ltd.

Dissolved and total organic and inorganic carbon in some British rivers

Rivers transport both organic and inorganic carbon from their sources to the sea. Results of ~800 organic and inorganic analyses from various British rivers of contrasting size and land use are presented here: (1) the headwater River Tern, a rural river of 852 km2 catchment; (2) the Ouseburn, a small urban 55 km2 catchment; (3) the River Tyne, a larger river system of ~3000 km2 catchment; (4) a spatial survey from 205 sample sites on ~60 rivers from SW England. We found that, with the exception of peat‐rich headwaters, DIC concentration is always greater than DOC. DIC is primarily in the form HCO3 − , with DIC concentrations highest in highly urbanised catchments, typically greater than those observed in catchments with carbonate bedrock, demonstrating a significant and previously unrecognised anthropogenic inorganic carbon input to urban rivers.

Three seedling emergence methods in soil seed bank studies: implications for interpretation of propagule deposition in riparian zones

AbstractSamples of soil and recently deposited sediments were collected from the river bed, bank face and bank tops of two lengths (reaches) of the River Frome, Dorset, UK and one reach of the River Tern, Shropshire, UK. Soil propagule bank samples were collected in May 2003, and depositional samples were collected subsequently over four consecutive 4-month periods between June 2003 and October 2004. The samples were subjected to three emergence trials under drained, waterlogged and submerged conditions. Significantly more seedlings germinated in the drained than waterlogged trial, and waterlogged than submerged trials. Drained, waterlogged and submerged trials identified 186, 76 and 37 species, respectively. Six species identified in the waterlogged trials were not identified in the drained trials, and five species in the submerged trials were not found in the drained trials. Submerged trials added two species to the drained and waterlogged results. Application of detrended correspondence analysis (DCA) to average species abundance data, for the sampled hydrological habitats (bed, bank face, bank top) within the soil propagule bank and four depositional data sets, generated different results for the three trials. The drained treatment revealed significant differences between sites, seasons and hydrological habitats, whereas the waterlogged and submerged treatments presented an increasingly homogeneous view of the samples. Our results confirm other propagule bank emergence comparisons and extend them to depositional samples, demonstrating that the strong environmental sieves imposed by waterlogging and submergence restrict emergence of numerous terrestrial, wetland and even some aquatic species that were successfully identified using the drained conditions.

The river‐bed: a dynamic store for plant propagules?

AbstractThis paper investigates temporal variations in the abundance, species composition and richness, and spatial distribution of plant propagules stored on river‐beds.Samples of the surface layers of river‐bed sediments were obtained from two reaches of the River Frome, Dorset, UK, and one reach of the River Tern, Shropshire, UK. Samples were taken from the same bed locations on four occasions spaced at approximately four monthly intervals. Following greenhouse germination trials, 11 384 viable propagules of 105 species were identified in 192 channel bed samples. On average, 32% of the species found in the propagule samples were not present in the channel and riparian vegetation. Most of these additional species were wetland and terrestrial rather than aquatic species. The number of species and density of propagules stored on the river‐bed varied through time and between reaches. These findings indicate that the channel bed is a dynamic store for viable propagules, including a large proportion of species that are not found locally. These propagules are available for redistribution across river‐banks and floodplains during high river flows.Propagules were preferentially stored within particular bed habitats. On the Tern, the most retentive habitats were close to the channel margins and adjacent to riparian vegetation and trees. On the Frome, stands of emergent vegetation along the channel margin were the most retentive habitat, and were also associated with trapping of finer sediment and organic matter. This habitat provides an aggrading environment at the bank toe that could potentially offer germination sites for the non‐aquatic propagules that are stored. Germination and growth of wetland and terrestrial plants during bank profile aggradation and lateral extension would provide root reinforcement and flow resistance across the changing bank profile. The preferential accumulation of sediment and species‐rich propagules around stands of marginal emergent vegetation is indicative of a subtle coupling of geomorphological and ecological systems. Copyright © 2007 John Wiley & Sons, Ltd.

Using stable isotopes of water to infer wetland hydrological dynamics

Abstract. This paper considers the potential of oxygen and hydrogen isotope ratios to identify spatial and temporal changes in the water source of a lowland headwater wetland situated adjacent to the River Tern in Shropshire, UK. Stable isotope composition (d18O) of end-members varied between –7.5 and –8.0‰ for groundwater, –7.3 and –8.5‰ for river-water and –4.5 and –8.0‰ for precipitation. Water samples were extracted from six nests each comprising three porous cup samplers at depths of 0.2 m, 0.5 m and 1.0 m between June 2000 and October 2001, and their isotope compositions determined. Groundwater appears to be the main source of water to the wetland, but stable isotope ratios enable seasonal variations in the contribution of precipitation to be determined, and indicate the extent of precipitation storage within the wetland. Keywords: oxygen and hydrogen isotopes, water source, hydrodynamics, lowland wetland

I.—On an Old Lake-basin in Shropshire

The district known as the Wealdmoors of Salop is an ancient lake-basin about seven miles in length, by four in width. It lies east of the Wrekin, from which the ground slopes gradually down to it. On the S.E., the high ground of Lilleshall, and its vicinity, rises more abruptly, and on the N.E. extremity it is intersected by the river Tern, which probably formed the principal outlet. The centre of the basin is filled with peat, containing remians of oak and hazel trees, very much decayed, and matted together by thick layers of fibrous roots, and in the lower part, by a species of moss, of which the fibre is too fine for the Sphagnum, but which it is impossible to identify, on account of its decayed condition. This peat attains a thickness of about six feet. Some years ago, a bronze celt of fine workmanship, and which is considered to have been manufactured since the commencement of the iron age, was found imbedded in it.