K E Y W O R D S Brandt's vole, climate change, human disturbance, local disappearance, range contraction, steppe grassland Defeng Bai and Xinru Wan contributed equally to this work and co-first author of this article.ĭespite the essential role that vertebrate scavengers play in ecosystems, most studies have been conducted in Europe and North America, and there is a lack of information on vertebrate scavengers in vast regions of the world. It is necessary to take actions to preserve the isolated populations of Brandt's voles from the effects of accelerated climate change and human disturbance. Our study suggests that the rapid climate change over the past decades contributed to the range contraction of its southern boundary of this keystone species in the steppe grassland of China. The disappearance threshold of maximum air temperature of Brandt's voles in the warmest month (27.50 ± 1.61☌) was similar to the lower critical temperature of its thermal neutral zone. The southern boundary retreated northward at a speed of 99.0 km per decade with the temperature rise of 0.36☌. Human stressors and high vegetation coverage increased the probability of local disappearance of voles in years of abundant precipitation. We found climate warming attributed to local disappearance and range contraction for southern populations of Brandt's voles from 1971 to 2020. We projected the distribution change of Brandt's voles under future climate warming scenarios. The year following the last observation year was used to estimate the disappearance threshold of Brandt's voles. We used logistic generalized additive models to quantify the relationship between local disappearance probability of Brandt's voles and environmental variables. In this study, we examined the association of climate warming and human disturbance stressors with local disappearance probability of Brandt's voles (Lasiopodomys brandtii) in a steppe grassland in northern China.
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Climate warming and human disturbance are known to be key drivers in causing range contraction of many species, but quantitative assessment on their distinctive and interactive effects on local disappearance is still rare. An extension to the known wintering range of the Steppe Eagle Aquila nipalensis, in the Poonch and Jhelum Valleys, Azad Jammu and Kashmir, Pakistan.ġ.
we suggest that the addition of the study area to the wintering range map of the species and recommend annual monitoring of the population. waste from slaughterhouses and other anthropogenic sources appeared to be the main food source since the largest eagle concentrations were at dump sites. Site counts averaged ten birds and ranged from 63 at Hajira, a waste dump, to just two, at Kalas. Mixed wintering groups of adults and immatures, averaging 154 individuals annually, were counted in two survey years. It adds another 6,730km2 to the known wintering range. The present study investigated new distributional records from the Poonch and Jhelum valleys of Azad Jammu and Kashmir, beyond the range of the current IUCN distribution map for Pakistan. The endangered Steppe Eagle Aquila nipalensis is a winter migrant to Pakistan but baseline data regarding its current distribution and population status there is sparse. Altitudes, height of nest location and nest size (diameter, depth, height) did not influence the number of eggs layed and young fledged successfully. All nests were located between 1100-2500 masl. Average clutch size was 1.9 (0.6 SD, 1-3, n=43) and the number of young fledged per pair was 0.89 (0.8, 0-3, n = 37).
Only one pair occupied a nest platform from among the 100 platforms built by our team in 2002. Breeding pairs prefer to nest in the midst of 20-30 cm high rocks or rock columns on top or on the side of hills in the center of active colonies of voles. Steppe Eagles are mostly ground nesters and their diet is comprised mostly of Brandt's Vole (Lasiopodomys brandti). The year did not affect nest site selection and there was no difference between type of nest site and clutch size or the number of young fledged successfully. Of the total of 49 nests evaluated, 22 (47.8%) were placed on the ground, 15 (32.6%) were on rock columns and large boulders, 4 (8.7%) on cliffs, one on a tree (2.2%), and 4 (8.7%) on artificial substrates (2 on abandoned car cabins, 1 on a car tyre and 1 on an artificial nest platform).
We studied 49 breeding pairs for a decade, 1998-2007. The Steppe Eagle is a migratory species in Mongolia that breeds in the forest, high mountains, and different types of steppes.
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