WII Technical Reports/Books/Manuals
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Item Causes of avian diversity gradients along the Himalayas(Wildlife Institute of India, Dehradun, 2016) Kumar, R.S.; Singh, P.; Mohan, D.; Gupta, S.K.; Rana, S.K.; Singh, A.Studies on bird species diversity across the Himalayan mountain range in India have shown that the southeast parts of the Himalaya has threefold more number of breeding bird species in comparable areas than northwest Himalaya (Price et al., 2011; White, 2016). To understand the causes of this diversity gradient along the Himalayas the present study was undertaken. For this study two phylogenetically coherent groups of flycatchers comprising 9 and 10 species respectively from the Ficedula/Muscicapella and Niltava/Cyornis genera were taken up. Phylogenetic coherence of the two groups was confirmed through a recent analysis of Himalayan passerines (Price et al, 2014). The flycatchers show a sharp decline in species number from southeast to northwest Himalaya as well as a similar mid-elevation peak corresponding to the pattern of all Himalayan passerines. The group also provides examples of species restricted to southeast (9 species), restricted to northwest (3 species) and widely distributed across Himalaya (7 species). Since resource distributions are critical to explain patterns of bird diversity, and because many bird species show strong habitat associations (Price 1991; Ghosh-Harihar and Price 2014), sampling for flycatcher distribution and abundance, vocalization, phylogenetic and habitat differences in associated vegetation from southeast to northwest Himalaya was carried out in this study. And, the fieldwork for this study was primarily conducted along two elevational gradients both in the southeast in parts of north Bengal and Sikkim, and for northwest Himalaya in parts of Jammu & Kashmir. The elevational distribution of the flycatchers showed a mid-elevational peak both in eastern and western Himalaya. In particular, the number of flycatcher species peaks at about 2000 m in the east, and plateaus from about 2000-3000 m in the west, albeit at lower levels than in the east. Previous studies had found evidence that insect food was highest at mid-elevations in the east and from east to west (Ghosh-Harihar & Price, 2014, Price et al., 2014), supporting the hypothesis that more food leads to more individuals leading to more species. The largest flycatcher species Niltava grandis and the smallest species Muscicapella hodgsoni are both confined to the middle elevations, as well as sallying species in the genera Muscicapa and Eumyias also occupied the mid-elevations, supporting the idea that a larger resource base allows for a finer partitioning of those resources. To understand whether the resources themselves are more diverse a comparison of foliage density with the flycatcher diversity along elevational gradients showed a correlation value of 0.65 for southeast and 0.33 for northwest Himalaya. The number of flycatcher species correlates well with the foliage density, except for low elevation sites in the east Himalaya, which have more foliage density and few flycatcher species. Thus, foliage density alone did not appear to explain the flycatcher pattern. Comparison of tree diversity showed a low-elevation peak in southeast and declining species number in northwest along the elevational gradients. In case of shrubs however, the variation in species diversity with increasing elevation is very less with no continuous increasing or decreasing pattern. Thus, the species diversity of woody vegetation hypothesized did not show similar patterns to the flycatcher diversity, as well as the overall avifaunal diversity along the elevational gradient. In this study, we found significant genetic differentiation between east and west populations of Slaty-blue Flycatcher Ficedula tricolor and Blue-throated Flycatcher Cyornis rubeculoides. The genetic divergence time in the populations of F. tricolor was estimated to be more than 4.6 Mya. In the case of C. rubeculoides apart from the population in the west two distinct populations occurring in the east with one found in the upper reaches above 900 m and the other to about 300 m were found. The divergence time between the west and eastern upper population was estimated to be more than 3 Mya, while the eastern populations was estimated to have diverged 4.7 Mya. These results suggest that the recolonisation of these species to the west is not a result of recent post glacial events, and qualify to be described as separate species. To conclude, the flycatcher species richness along the elevational gradient correlated with arthropod abundance and as well with plant biomass (primary productivity), but not with the plant species richness. The reason for this may be attributed to the nature of dispersal and seasonality since unlike plants birds are highly mobile and majority of these species are summer migrants. The creation of new climatic regime after last glacial maxima has resulted in a climatic gradient which in turn is shaping the biological communities across the Himalaya. The disparity in species number from southeast to northwest is a combined result of prevalent climatic conditions coupled with community assembly processes like competition, productivity, resource availability, dispersal ability, and evolutionary dynamics.Item Assessing the impacts of Power-lines on avian species in the Arid plains of Western Gujarat : Final Technical Report(Wildlife Institute of India, Dehradun, 2021) Kumar, R.S.; Baroth, A.The Kachchh landscape in western Gujarat has witnessed rapid industrial growth in the last few decades. Also, the landscape has a high potential for wind energy generation and as a result, a number of wind farms have been established and continue to expand. Rapid industrialization and wind energy production has resulted in extensive power-line network crisscrossing the landscape. These energy infrastructures are known to pose potential risks to birds primarily those that are large-bodied in the form of collision and electrocution mortality. In lieu of this, a -four study was carried out in the Kachchh landscape to assess the impact of power-lines on large avian species in the arid plains of western Gujarat. In order to assess the power-line collision risk, data were collected at multiple levels, which includes (1) mapping the network of transmission lines in the Kachchh district, (2) GPS telemetry of six flamingos (two Greater and four Lesser Flamingo) (3) flight behavior of cranes around power-line, and (4) mortality surveys. The distribution and abundance of migratory Raptors were studied on three selected sites across Kachchh to know the electrocution risk to raptors. Also, surveys were carried out to collect data on space use by Common Crane with respect to wind farms to study the impacts of windmills on large birds. Finally, the data were analyzed using GIS modelling and various R packages to understand the space-use by large birds and identify risky power-line stretches that could pose threats to large birds. The analysis of Flamingo distribution surveys revealed that greater flamingos are widely distributed and occur in a much larger area than Lesser Flamingo. The analysis of tracking data showed that Flamingos make a greater number of flights during the breeding season. Further, it was documented that Lesser Flamingo use saltpans and mudflats primarily while Greater Flamingo used inland wetlands and coastal areas more often. The comparison of flight time showed that flamingos make most of the flights during night time. In the case of Cranes, Common cranes occurred in both agricultural and grassland habitats, while Demoiselle cranes were more localized and used only agricultural fields and feeding stations where local people practice food provisioning. Flamingos tracking data helped identify two main flight corridors, one at Nanda Bet and one at Surajbari, through which they made flights. These two corridors are also the only entry points from mainland Gujarat to Kachchh and hence are the corridor for transmission lines. As a result, these transmission lines are suggested to be a potential threat to Flamingos. The overlaying of transmission lines on the suitable habitat of Flamingos and Cranes revealed that 6% and 39% of the total power-line length is falling in Flamingo and Crane suitable habitats, respectively. It was found that 84.4% and 70% of total occasions, Lesser Flamingo and Greater Flamingo crossed power-lines during night times while making long-distance flights. The flight behavior observations of Common Crane around power-lines showed that 81% of total flocks observed altered either their flight path or their flight height.The data on raptor distribution with respect to distribution lines revealed that the Banni area has a high encounter rate (0.6 sightings/km) of raptor species and is home to several large raptors. The distribution lines in the Kachchh district do not have bird-safe spacing between conducting parts and hence can pose a potential risk to large raptors. The study investigating the impact of windmills on the space-use by Common Crane revealed that the encounter rate of Common Crane flocks in the areas dominated by windmills is six times less than in the areas with no windmills, suggesting possible functional habitat loss for the large birds due to windmills. This study is the first detailed landscape-scale effort to assess risks by energy infrastructure on avian species that forms a baseline for any future site-specific impact assessment studies in the region. This project identified the areas where powerlines likely pose a threat to large birds such as Flamingo and Crane. This study also suggests different strategies to minimize the impacts of existing and future energy infrastructure in different habitats in the Kachchh region