A decline in snow cover area of Passu and Ghulkin valleys between 1995 and 2022

The global cryosphere is experiencing accelerated melting due to climate change.Currently,the Karakoram anomaly is under discussion with a debate about the possibility that the anomaly may have recently ended.This study aims to evaluate the up-to-date changes in snow cover in the western Karakoram region.We observed the snow cover changes in Passu and Ghulkin valleys in the Hunza River basin(HRB)of the Karakoram through multitemporal Landsat satellite data between 1995 and 2022.We found a significant reduction in snow cover in these valleys,with an average reduction rate of 0.42 km~2/yr,resulting in a total reduction of~11.46 km~2 between 1995 and 2022.This reduction in snow cover is consistent with the mass loss of glaciers in the Karakoram region in recent years.The decline in snow cover in these valleys is also consistent with the meteorological data.The temperature in summer(June)has significantly increased whereas the precipitation in the accumulation season(March)has decreased.These rapid changes suggest that it is crucially important to monitor the snow cover on a regular basis to support downstream management of snowmelt runoff.In addition,there is a need of planning for mitigation and adaptation strategies for snow-related hazards.

Using Landsat images to monitor changes in the snow-covered area of selected glaciers in northern Pakistan

Landsat satellite images were used to map and monitor the snow-covered areas of four glaciers with different aspects(Passu: 36.473°N, 74.766°E;Momhil: 36.394°N, 75.085°E; Trivor: 36.249°N,74.968°E; and Kunyang: 36.083°N, 75.288°E) in the upper Indus basin, northern Pakistan, from 1990-2014. The snow-covered areas of the selected glaciers were identified and classified using supervised and rule-based image analysis techniques in three different seasons. Accuracy assessment of the classified images indicated that the supervised classification technique performed slightly better than the rule-based technique. Snow-covered areas on the selected glaciers were generally reduced during the study period but at different rates. Glaciers reached maximum areal snow coverage in winter and premonsoon seasons and minimum areal snow coverage in monsoon seasons, with the lowest snow-covered area occurring in August and September. The snowcovered area on Passu glacier decreased by 24.50%,3.15% and 11.25% in the pre-monsoon, monsoon and post-monsoon seasons, respectively. Similarly, the other three glaciers showed notable decreases in snow-covered area during the pre-and post-monsoon seasons; however, no clear changes were observed during monsoon seasons. During pre-monsoon seasons, the eastward-facing glacier lost comparatively more snow-covered area than the westward-facing glacier. The average seasonal glacier surface temperature calculated from the Landsat thermal band showed negative correlations of-0.67,-0.89,-0.75 and-0.77 with the average seasonal snowcovered areas of the Passu, Momhil, Trivor and Kunyang glaciers, respectively, during pre-monsoon seasons. Similarly, the air temperature collected from a nearby meteorological station showed an increasing trend, indicating that the snow-covered area reduction in the region was largely due to climate warming.

Spatio-temporal changes in the six major glaciers of the Chitral River basin(Hindukush Region of Pakistan)between 2001 and 2018

Glaciers in the northern Pakistan are a distinctive source of freshwater for the irrigation,drinking and industrial water supplies of the people living in those regions and downstream. These glaciers are under a direct global warming impact as indicated in many previous studies. In this study, we estimated the glacier dynamics in terms of Equilibrium Line Altitude(ELA), mass balance and the snout position variation using remote sensing data between 2001 and 2018. Six glaciers, having area≥ 20 km2 each, situated in the Chitral region(Hindukush Mountains) were investigated in this study. Digital Elevation Model(DEM) and available cloud-free continuous series of Landsat and Sentinel satellite images from minimum snow cover season were used to monitor the variability in the studied glaciers by keeping the status of glaciers in year 2001 as a reference. The annual climatic trends of mean temperature and total precipitation from Chitral weather station were detected using the nonparametric Mann-Kendall’s test. Results revealed a general increase in the ELA, decrease in the glacier mass balance and the retreat of snout position.Average upward shift in the ELA for the entire study area and data period was ~345 ± 93 m at a rate of^13 m.a-1 from the reference year’s position i.e.~4803 m asl. Estimated mean mass balance for the entire study area indicated a decline of-0.106 ± 0.295 m w.e. a-1. Periods of snout retreat and advance in different glaciers were found but the mean value over the entire study area was a retreat of-231 ± 140 m.No obvious relationship was found between the glacier variation trends and the available gauged climatic data possibly due to the presence of debris cover in ablation zones of all the studied glaciers which provides insulation and reduces the immediate climatic effects.

Erratum to:Spatio-temporal changes in the six major glaciers of the Chitral River basin(Hindukush Region of Pakistan)between 2001 and 2018

The article Spatio-temporal changes in the six major glaciers of the Chitral River basin(Hindukush Region of Pakistan)between 2001 and 2018,written by Jawaria GUL,Sher MUHAMMAD,LIU Shi-yin,Siddique ULLAH,Shakeel AHMAD,Huma HAYAT and Adnan Ahmad TAHIR,was originally published Online First without Open Access.After publication in volume 17,issue 3,page 572-587,the author decided to opt for Open Choice and to make the article an Open Access publication.Therefore,the copyright of the article has been changed to C The Author(s)2020 and the article is forthwith distributed under the terms of the Creative Commons Attribution 4.0 International License(http://creativecommons.org/licenses/by/4.0/),which permits use,duplication,adaptation,distribution and reproduction in any medium or format,as long as you give appropriate credit to the original author(s)and the source,provide a link to the Creative Commons license,and indicate if changes were made.The original version of this article has been revised due to a retrospective Open Access order.

Genome-wide association analysis for stripe rust resistance in spring wheat(Triticum aestivum L.) germplasm

Stripe rust is a continuous threat to wheat crop all over the world.It causes considerable yield losses in wheat crop every year.Continuous deployment of adult plant resistance(APR)genes in newly developing wheat cultivars is the most judicious strategy to combat this disease.Herein,we dissected the genetics underpinning stripe rust resistance in Pakistani wheat germplasm.An association panel of 94 spring wheat genotypes was phenotyped for two years to score the infestation of stripe rust on each accession and was scanned with 203 polymorphic SSRs.Based on D’measure,linkage disequilibrium(LD)exhibited between loci distant up to 45 c M.Marker-trait associations(MTAs)were determined using mixed linear model(MLM).Total 31 quantitative trait loci(QTLs)were observed on all 21 wheat chromosomes.Twelve QTLs were newly discovered as well as 19 QTLs and 35 previously reported Yr genes were validated in Pakistani wheat germplasm.The major QTLs were QYr.uaf.2 AL and QYr.uaf.3 BS(PVE,11.9%).Dissection of genes from the newly observed QTLs can provide new APR genes to improve genetic resources for APR resistance in wheat crop.

Identifying glyphosate-tolerant maize by soaking seeds in glyphosate solution

The identification of glyphosate-tolerant maize genotypes by field spraying with glyphosate is time-consuming, costly and requires treatment of a large area. We report a potentially better technique of seed-soaking to identify glyphosate-tolerant maize genotypes. The effects of soaking maize seeds in glyphosate solution under controlled conditions were studied on seed germination rate, seedling morphological indices, seedling growth and leaf chlorophyll content. These responses were compared among a glyphosate-tolerant transgenic maize cultivar CC-2, glyphosate-susceptible inbred line Zheng 58（the recurrent parent of CC-2） and hybrid cultivar Zhengdan 1002. The results showed that the germination rate, seedling morphological indices and leaf chlorophyll content of glyphosate-tolerant CC-2 seeds did not change significantly among five different concentrations of glyphosate treatment（0 to 2%）. In contrast, germination rates, seedling morphological indices and leaf chlorophyll contents of Zheng 58 and Zhengdan 1002 seeds were significantly negatively affected by exposure to increasing concentrations of glyphosate. The glyphosate-tolerant inbred line CC-2 displayed a strong tolerance to glyphosate after soaking in 0.1 to 2.0% glyphosate solutions, while both the inbred line Zheng 58 and hybrid Zhengdan 1002 were susceptible to glyphosate. The accuracy of the glyphosate-soaking method for screening glyphosate-tolerant maize was confirmed using a field spraying trial.

喜马拉雅山区高山冰缘植物并不能从变暖中受益

普遍认为变暖有利于高山植被生态系统,并已经导致冰缘植物向高海拔的扩张.珠峰山谷金字塔气象站(海拔5050 m)1994~2018的气象记录显示,高海拔山区呈显著的暖干化趋势.然而,我们依然不清楚暖干化是否对冰缘植被更新和分布造成显著影响?本研究在喜马拉雅山中段3个山谷建立了8块(30 m×120 m)滇藏方枝柏(Juniperus indica)和高山柏(Juniperus squamata)灌木线样地(海拔介于4344~5074 m之间).样地调查揭示,自20世纪90年代之前所有样地种群更新呈增加的趋势,然而90年代以来更新持续下降.种群更新与春季、夏季温度之间呈现显著的负相关关系,暗示了暖干化加剧了水分胁迫,并限制了种群的更新.另外,近60年来所有灌木线位置稳定.近30年遥感数据也证实,研究区冰缘植被无变绿趋势,甚至出现2%-6%的植被生长减弱现象.因此,进一步研究应该探讨冰缘植被生长减弱对喜马拉雅山区水循环和生物多样性的影响.