Black-necked Crane Grus Nigricollis Research Articles

Imperiled Prancing Crane: Population Status and Breeding Performance of Black-Necked Crane Grus nigricollis in Trans-Himalayan Ladakh Region

Imperiled Prancing Crane: Population Status and Breeding Performance of Black-Necked Crane Grus nigricollis in Trans-Himalayan Ladakh Region

Disturbance and predation risk influence vigilance synchrony of black-necked cranes Grus nigricollis, but not as strongly as expected.

Animals monitor surrounding dangers independently or cooperatively (synchronized and coordinated vigilance), with independent and synchronized scanning being prevalent. Coordinated vigilance, including unique sentinel behavior, is rare in nature, since it is time‐consuming and limited in terms of benefits. No evidence showed animals adopt alternative vigilance strategies during antipredation scanning yet. Considering the nonindependent nature of both synchronization and coordination, we assessed whether group members could keep alert synchronously or in a coordinated fashion under different circumstance. We studied how human behavior and species‐specific variables impacted individual and collective vigilance of globally threatened black‐necked cranes (Grus nigricollis) and explored behavior‐based wildlife management. We tested both predation risk (number of juveniles in group) and human disturbance (level and distance) effects on individual and collective antipredation vigilance of black‐necked crane families. Adults spent significantly more time (proportion and duration) on scanning than juveniles, and parents with juveniles behaved more vigilant. Both adults and juveniles increased time allocation and duration on vigilance with observer proximity. Deviation between observed and expected collective vigilance varied with disturbance and predation risk from zero, but not significantly so, indicating that an independent vigilance strategy was adopted by black‐necked crane couples. The birds showed synchronized vigilance in low disturbance areas, with fewer juveniles and far from observers; otherwise, they scanned in coordinated fashion. The collective vigilance, from synchronized to coordinated pattern, varied as a function of observer distance that helped us determine a safe distance of 403.75 m for the most vulnerable family groups with two juveniles. We argue that vigilance could constitute a prime indicator in behavior‐based species conservation, and we suggesting a safe distance of at least 400 m should be considered in future tourist management.

Evaluation of potential ecological risk, possible sources and controlling factors of heavy metals in surface sediment of Caohai Wetland, China

Caohai, a plateau wetland in Southwest China, is a national nature reserve providing protection for a variety of threatened and endangered species of migrant birds (e.g., the black-necked crane Grus nigricollis). It has been experiencing the increasing environmental problems with heavy metals due to anthropogenic activities. However, the contamination of heavy metals in different habitats is unclear. Surface sediment samples from these habitats were thus collected to analyze the distribution characteristics, potential risk and possible sources for heavy metals (Cd, Hg, Pb, Zn, Ni, Cr, Cu, Be, and V). The results showed that all of Cd, Hg, Pb, Zn, Cr, and Ni concentrations exceeded the background values, and these elements (except Cr and Ni) presented comparatively high levels in habitat adjacent to urban in comparison with the other habitats. Based on the regression analysis, we found that metals with higher EFs (Cd, Hg, Pb, and Zn) were mainly controlled by anthropogenic loadings, while metals with lower EFs (Cr, Ni, Be, and V) were mainly associated with sediment properties (pH or NOM). In addition, the results from geo-accumulation index, Hakanson potential ecological risk assessment, and risk assessment code showed that Cd and Hg posed a medium to high environmental risk to the ecosystem, and the other heavy metals posed no or low risk. Therefore, to protect this wetland ecosystem and to supply a well habitat for migratory birds, greater efforts aimed at reducing anthropogenic discharges and remediating sediment contaminated with heavy metals should be pursued.

The pattern of waterbird diversity of the trans-Himalayan wetlands in Changthang Wildlife Sanctuary, Ladakh, India

Ladakh lies on an important bird migratory route between the Palearctic and the Indian sub-continent, and the high altitude migratory species utilise Ladakh frequently as a stopover site. The trans-Himalayan landscape in Ladakh also serves as a breeding site for many water birds species including the globally threatened Black-necked Crane Grus nigricollis. Yet, only sporadic information is available on the status and diversity of waterbirds here. In a landscape-level assessment study spanning over 27,000km2 area, we surveyed 11 major high-altitude wetlands of Changthang Wildlife Sanctuary, Ladakh during the pre-winter season of the year 2013. We recorded a total of 38 waterbird species belonging to 10 families, including one species in Vulnerable and two species in Near Threatened categories of IUCN Red List. We calculated species diversity and richness indices to compare the wetlands. Statapuk Tso and Tsokar were the most diverse wetlands of the sanctuary (Shannon diversity 2.38 and 2.08, respectively). We used principal component analysis to find out the wetlands with unique species assemblage and identify the sites with high conservation value. We also observed a directional pattern of diversity among the wetlands of Ladakh. We provide a reminder that wildlife even in protected areas should be surveyed regularly with the sources of threats to their conservation documented carefully.

Two new locations for the Vulnerable Black-necked Crane Grus nigricollis (Przhevalsky, 1876) (Aves: Gruiformes: Gruidae) in Arunachal Pradesh, India

The Vulnerable Black-necked Crane Grus nigricollis is a known migrant to various locations in India. Here, we report two new locations in Arunachal Pradesh, north-east India, where one is a possible wintering location and the other a possible stopover en route their migration. One new location in Shergaon (western Arunachal Pradesh) is relatively close to previous locations; however, the one in Mechuka (central Arunachal Pradesh) is some distance away from previous records which is highly intriguing. These records of this threatened species will hopefully assist with local conservation measures, bring about more rigorous monitoring, and more surveys for these rare species in the region.

Conservation prioritization with machine learning predictions for the black-necked crane Grus nigricollis, a flagship species on the Tibetan Plateau for 2070

Ongoing global climate change greatly alters the distribution of species, and such impacts are even amplified on the Tibetan Plateau. The black-necked crane (Grus nigricollis) is perceived as an environmental indicator and flagship species in the alpine wetland ecosystems. However, scientifically, sound knowledge about global change impact on its breeding habitats is still lacking. Therefore, based on the best available species data further linked with powerful machine learning methods (ensemble random forest model), we predicted the breeding distribution of the black-necked crane under 2070 climate scenarios and provided associated conservation solutions. Our models for 2070 showed that its breeding range would expand in the hinterland of the Tibetan Plateau, with the current breeding habitats slightly shrinking from exterior margins, and in 2070, the overall habitat suitability would be jeopardized by the dwindling high-suitability habitats. Furthermore, conservation prioritization analyses indicated that global change would impact future-focused conservation and management, whereas the conservation effectiveness of the existing reserve networks would be instead improved with aggravating climate change and that the missing high conservation value areas are also spatially consistent on the Tibetan Plateau. Consequently, one elaborately designed reserve network could be feasible to secure this unique alpine crane lineage as well as the overwhelming majority of water birds on the Tibetan Plateau, despite the serious climate change impacts in the next realizable 50 years.

Nest size and its Contributing Factors for Black-Necked Cranes Grus nigricollis

Nest size and its Contributing Factors for Black-Necked Cranes Grus nigricollis

Can sequential vigilance be predicted?

Sequential randomness is one of the three important assumptions for Pulliam’s vigilance model (1973). Here we tested the sequential randomness in Black-necked cranes Grus nigricollis, to see if the vigilance sequence can be predicted. Not similar to other recent studies, we found that most vigilance sequences (44/46) passed runs randomness test, and the length of an inter-scan interval was usually unrelated to its previous scan duration. Our findings suggest high predation risk might favor a random pattern of vigilance.

Winter habitat selection by the Vulnerable black-necked craneGrus nigricollisin Yunnan, China: implications for determining effective conservation actions

AbstractHabitat change has major effects on wildlife and it is important to understand how wild animals respond to changing habitats. Dashanbao National Nature Reserve, in north-east Yunnan, China, which was established for the protection of the black-necked craneGrus nigricollis, other wintering waterbirds and the upland wetland ecosystem, recently began converting farmland to grassland and woodland. With respect to this policy we studied habitat selection by black-necked cranes in the Reserve from November 2006 to April 2007. Farmland, grassland, marsh and water were used by black-necked cranes but no cranes occurred in man-made woodland. Black-necked cranes showed the least preference for grassland and no significant differences were detected in the species’ preference for the other three habitats. However, black-necked cranes exhibited different behavioural responses to the four habitats: farmland and grassland were their main foraging sites. Principle component analysis verified that a foraging-related component was the first factor determining habitat selection. Cranes used habitat close to their roosts with short grass, shallow water and less disturbance by human activity. Our results indicate that the policy of converting farmland and grassland to woodland is not beneficial for conservation of the crane. For effective conservation of the black-necked crane scientific habitat management that takes into account habitat selection by the species is required, with the retention of some farmland and restoration of wetlands.

Nest site selection by Black-necked Crane Grus nigricollis in the Ruoergai Wetland, China

From 5 May 2003 to early June 2005, nest site selection of Black-necked Cranes Grus nigricollis was studied at the Ruoergai Wetland Nature Reserve (RWNR), an important breeding area for the species in China. Results showed that the crane nests only in wetland environments, including lake, swamp and river microhabitats. However, the bird showed different selection patterns in these microhabitats. According to the Ivelev selectivity index (S.I.), cranes preferred lakes and avoided swampy areas, while they used river areas in proportion to their availability. Factors associated with the selection of nest sites included water body size, distance to water, water depth and the level of nest concealment. Nest size was a function of the microhabitat used for nesting; nests were largest in lakes, and similarly-sized in swamp and river habitats. A certain water depth was a prerequisite for nest site selection (mean = 31.1 cm), but no differences were found among different microhabitats. Compared with nests found in Qinghai, Tibet, and Ladakh, nests in Ruoergai Wetland were smaller, but water depth near nesting sites was higher (mean = 31.1 cm vs 18.2 cm). Different plant communities, climate and disturbance are likely to be related to these differences. Conservation efforts should focus on the protection of existing lakes, minimizing disturbance impacts and maintaining small patches (i.e. 100 m2 water bodies) of swamp areas as important buffer zones. In the future, restoration of wetlands to decrease fragmentation, and reduction of habitat degradation are advocated for effective conservation of this species.