Many bird species in montane regions exhibit altitudinal migration behavior;however,altitudinal migration of birds is still understudied,especially in Asia.Mt.Gongga(7556 m) is the highest peak of the Hengduan Mountai...Many bird species in montane regions exhibit altitudinal migration behavior;however,altitudinal migration of birds is still understudied,especially in Asia.Mt.Gongga(7556 m) is the highest peak of the Hengduan Mountains in Southwest China.The steep elevation gradient and the high bird diversity make the eastern slope of Mt.Gongga(Hailuo Valley) an ideal place for studying the altitudinal migration behavior patterns of birds.We synchronously recorded the local bird diversity,temperature and humidity at two sites(1800 and 3000 m a.s.l.) during three migration seasons from September 2020 to June 2021 to identify birds exhibiting altitudinal migration behavior.During our surveys,we recorded 146 bird species in total and 20 passerine bird species were altitudinal migrants according to our altitudinal migration formula.Among those 20 altitudinal migrant species,eight bird species displayed a typical altitudinal migration pattern(upward migration during the breeding season and downward migration during the non-breeding season).Moreover,temperature was correlated with the daily number of individuals(DNI) at each study site.Therefore,increasing temperatures possibly caused upward migration of birds(DNI decreased at 1800 m and increased at 3000 m) and vice versa.To further elaborate,the Rufousgorgeted Flycatcher(Ficedula strophiata),the species with the most prominent altitudinal migration behavior,initiated upward migration at a temperature of 11-12℃ at 1800 m and initiated downward migration at a temperature of 12-13℃ at 3000 m.Besides,humidity was positively correlated with the DNI.Therefore,increasing humidity(equals to increasing rainfall or snow) possibly caused downward migration of birds(DNI increased) and vice versa.Furthermore,bird species exhibiting a typical altitudinal migration behavior pattern are feeding on insects.Thus,the spatial and temporal changes of the invertebrate biomass might be an important ecological driver for the altitudinal migration of invertivorous(birds eating invertebrates) birds.This study provides fundamental data for the altitudinal migration of birds in the Hengduan Mountains and shows how altitudinal migration is seasonally dynamic across an elevational gradient in a subtropical mountain region.展开更多
Background:In biological systems,biological diversity often displays a rapid turn-over across elevations.This defining feature has made mountains classic systems for studying the spatial variation in diversity.Because...Background:In biological systems,biological diversity often displays a rapid turn-over across elevations.This defining feature has made mountains classic systems for studying the spatial variation in diversity.Because patterns of elevational diversity can vary among lineages and mountain systems it remains difficult to extrapolate findings from one montane region to another,or among lineages.In this study,we assessed patterns and drivers of avian diversity along an elevational gradient on the eastern slope of Mt.Gongga,the highest peak in the Hengduan Mountain Range in central China,and a mountain where comprehensive studies of avian diversity are still lacking.Methods:We surveyed bird species in eight 400-m elevational bands from 1200 to 4400 m a.s.l.between 2012 and 2017.To test the relationship between bird species richness and environmental factors,we examined the relative importance of seven ecological variables on breeding season distribution patterns:land area(LA),mean daily temperature(MDT),seasonal temperature range(STR),the mid-domain effect(MDE),seasonal precipitation(SP),invertebrate biomass(IB) and enhanced vegetation index(EVI).Climate data were obtained from five local meteorological stations and three temperature/relative humidity smart sensors in 2016.Results:A total of 219 bird species were recorded in the field,of which 204 were recorded during the breeding season(April–August).Species richness curves(calculated separately for total species,large-ranged species,and smallranged species) were all hump-shaped.Large-ranged species contributed more to the total species richness pattern than small-ranged species.EVI and IB were positively correlated with total species richness and small-ranged species richness.LA and MDT were positively correlated with small-ranged species richness,while STR and SP were negatively correlated with small-ranged species richness.MDE was positively correlated with large-ranged species richness.When we considered the combination of candidate factors using multiple regression models and model-averaging,total species richness and large-ranged species richness were correlated with STR(negative) and MDE(positive),while small-ranged species richness was correlated with STR(negative) and IB(positive).Conclusions:Although no single key factor or suite of factors could explain patterns of diversity,we found that MDE,IB and STR play important but varying roles in shaping the elevational richness patterns of different bird species categories.Model-averaging indicates that small-ranged species appear to be mostly influenced by IB,as opposed to large-ranged species,which exhibit patterns more consistent with the MDE model.Our data also indicate that the species richness varied between seasons,offering a promising direction for future work.展开更多
Based on biomass investigations, soil respiration an d plant photosynthesis measurement of dominant trees in Hailuogou valley o f Mt. Gongga, Southwest China, the carbon (C) storage, absorption and release for several...Based on biomass investigations, soil respiration an d plant photosynthesis measurement of dominant trees in Hailuogou valley o f Mt. Gongga, Southwest China, the carbon (C) storage, absorption and release for several typical woodlands in sub-alpine zones have been di scussed. For Abies fabri forest of 3,000 m above sea level, the C stor age amount is 177.4 t/ha for above-ground biomass and 143.2 t/ha for s oil below-ground biomass. The annual gross C fixed by vegetation photo synthesis is 20-24 t/ha. The C release by canopy respiration is 3.0-5.5 t/ha for arbors and 10-19 t/ha for surface soil and roots. The annual net C f ixed of forest ecosystem is about 6.0-7.1 t/ha. At lower elevations, t he amount of C released by woodlands is higher than that of woods a t higher elevations. The C fixed capacity of renewed forest with middle-aged t rees is higher than that of mature forest. Before becoming over-matured forest, woodland is an important sink of C whereas bareland in woods is the source of atmospheric C.展开更多
On 5th September 2022,a magnitude Ms-6.8 earthquake occurred nearby Mt.Gongga,western Sichuan.The stability of the glaciers in east Mt.Gongga close to the epicenter was widely concerned due to the strong shake trigger...On 5th September 2022,a magnitude Ms-6.8 earthquake occurred nearby Mt.Gongga,western Sichuan.The stability of the glaciers in east Mt.Gongga close to the epicenter was widely concerned due to the strong shake triggered by the earthquake.Using multi-source observations(including in-situ photographs,remote sensing datasets before and after the event),we carried out a preliminary assessment of the stability and hazard risks of the Hailuogou(HLG)glacier.Triggered by the earthquake,a small block of fractured ice at the lowest part of icefall collapsed.The magnitude of the coseismic ice avalanche was relatively small,which is comparable in size to most ice avalanches over the past seven years,but much less than the previous mapped largest one(03 April 2018,runout~699 m).One most recent large(runout~608 m)ice avalanche occurred between 01 and 04 September,just before the earthquake,likely unloaded large amount of ice mass and made a larger ice avalanche avoided during the earthquake shake.Nevertheless,the momentum of collapsed snow-icerock mass could be safely unloaded over a wide and gentler-slope ice tongue area,limiting its mobility and the risk of a cascading hazard.Glacier-wide surface flow dynamics monitored by Sentinel-1 satellite SAR time series(12 September 2021–19 September 2022)show that HLG glacier velocity was generally consistent before and after the earthquake.The entire HLG glacier exhibited more stable than expected,with almost no abnormal features detected in its upper accumulation part,the lower ice tongue,and its lateral paraglacial slopes.Since the glacier valley has experienced remarkable downwasting and the paraglacial environment has been strongly disturbed and destabilized,we suggested that,to efficiently evaluate glacier-related cascading hazard risks,it is also necessary to systematically combine multi-source observations(e.g.,high-resolution UAV survey,radar/Lidar scan,ground investigation,monitoring and warning systems)to continuously monitor the regional glacier anomalies in the post-earthquake seismic active areas.展开更多
Great change, associated with global warming, has occurred at the Hailuogou （海螺沟） glacier, Mt. Gongga （贡嘎）, China, since the early 20th century. Various data indicate that the glacier has retreated 1 822 m in...Great change, associated with global warming, has occurred at the Hailuogou （海螺沟） glacier, Mt. Gongga （贡嘎）, China, since the early 20th century. Various data indicate that the glacier has retreated 1 822 m in the past 106 years, with an annual mean retreat of 17.2 m, and the front elevation has risen by 300 m since 1823. Comparison of glacier variations and temperature fluctuations in China and the Northern Hemisphere, over the last 100 years, indicates that glacier retreat stages occurred during the warm phase, and vice versa. Mass balance records during 1959/60-2003/04 have shown that the glacier has suffered a constant mass loss of snow and ice. The accumulated mass balance, -10.83 m water equivalent, indicates an annual mean value of -0.24 m water equivalent. The correlation between the mass balance and temperature is significant, which also indicates that climate warming is the crucial cause of glacier loss. Local hydrological and climatic data demonstrate that runoff from the glacier has been increasing both seasonally and annually. The correlation analysis and trend analysis indicate that ice and snow melted water is the main cause of an increase in the runoff. As the climate has become warmer, changes in the glacier surface morphology have obviously occurred. These include a decrease in glacier thickness, enlargement of glacial caves, and reduction of the size of clefts on the glacier surface. The ablation period has lengthened and the ablation area has expanded. A variety of factors thus provide evidence that the Hailuogou glacier has suffered a rapid loss of snow and ice as a result of climatic warming.展开更多
Background:Global climate change has had significant effects on animal distribution and population dynamics in mid-latitude alpine areas,but we know little about the basic ecology of high-altitude species due to the d...Background:Global climate change has had significant effects on animal distribution and population dynamics in mid-latitude alpine areas,but we know little about the basic ecology of high-altitude species due to the difficulties of conducting field research in the harsh climate and habitat present at high elevations.The Tibetan Snowcock(Tetraogallus tibetanus) is a little-known phasianid distributing in alpine areas at extremely high elevations in the mountains surrounding the Tibetan Plateau.Estimating the species occupancy rate and discussing the factors affecting its distribution based on infrared-triggered camera techniques would provide both a baseline to measure the influence of global warming and valuable information on its conservation and ecology.Methods:We used infrared-triggered cameras to investigate the Tibetan Snowcock on the western slope of Mt.Gongga from June to November 2016.We used the R package "overlap" to visualize its activity pattern,and used an occupancy model to both examine its habitat use as well as to determine the most influential variables affecting its habitat use.Results:Using 103 camera traps over 9213 camera-days,we recorded 428 instances of Tibetan Snowcock.The diel activity peaks of Tibetan Snowcock occurred during the periods of 8:00-10:00 am and 18:00-20:00 pm.The model estimate of occupancy for Tibetan Snowcock(0.830) was slightly higher than the na?ve site occupancy based on camera detections(0.663),indicating a wider use of habitat than the camera traps recorded.Elevation,slope,settlement density,road density,and EVI(enhanced vegetation index) were the most influential variables for its habitat use.Conclusions:The Tibetan Snowcock is confirmed to be diurnal.This species prefers an environment with a high elevation,gentle slope,and low EVI,apparently facing a trade-off between predator risk,foraging efficiency,and food availability.When human impact was low,there was a positive correlation between the habitat use of the Tibetan Snowcock and both its road and settlement densities.Infrared cameras and proper survey design are valuable for investigating extreme alpine phasianids.展开更多
基金the National Natural Science Foundation of China(No.32270454)the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019QZKK0501).
文摘Many bird species in montane regions exhibit altitudinal migration behavior;however,altitudinal migration of birds is still understudied,especially in Asia.Mt.Gongga(7556 m) is the highest peak of the Hengduan Mountains in Southwest China.The steep elevation gradient and the high bird diversity make the eastern slope of Mt.Gongga(Hailuo Valley) an ideal place for studying the altitudinal migration behavior patterns of birds.We synchronously recorded the local bird diversity,temperature and humidity at two sites(1800 and 3000 m a.s.l.) during three migration seasons from September 2020 to June 2021 to identify birds exhibiting altitudinal migration behavior.During our surveys,we recorded 146 bird species in total and 20 passerine bird species were altitudinal migrants according to our altitudinal migration formula.Among those 20 altitudinal migrant species,eight bird species displayed a typical altitudinal migration pattern(upward migration during the breeding season and downward migration during the non-breeding season).Moreover,temperature was correlated with the daily number of individuals(DNI) at each study site.Therefore,increasing temperatures possibly caused upward migration of birds(DNI decreased at 1800 m and increased at 3000 m) and vice versa.To further elaborate,the Rufousgorgeted Flycatcher(Ficedula strophiata),the species with the most prominent altitudinal migration behavior,initiated upward migration at a temperature of 11-12℃ at 1800 m and initiated downward migration at a temperature of 12-13℃ at 3000 m.Besides,humidity was positively correlated with the DNI.Therefore,increasing humidity(equals to increasing rainfall or snow) possibly caused downward migration of birds(DNI increased) and vice versa.Furthermore,bird species exhibiting a typical altitudinal migration behavior pattern are feeding on insects.Thus,the spatial and temporal changes of the invertebrate biomass might be an important ecological driver for the altitudinal migration of invertivorous(birds eating invertebrates) birds.This study provides fundamental data for the altitudinal migration of birds in the Hengduan Mountains and shows how altitudinal migration is seasonally dynamic across an elevational gradient in a subtropical mountain region.
基金supported by the National Natural Science Foundation of China Granted to Yongjie Wu(No.31501851,31772478)the Chinese Academy of Sciences Visiting Professorship for Senior International Scientists to Per Alstrom(No.2011T2S04)
文摘Background:In biological systems,biological diversity often displays a rapid turn-over across elevations.This defining feature has made mountains classic systems for studying the spatial variation in diversity.Because patterns of elevational diversity can vary among lineages and mountain systems it remains difficult to extrapolate findings from one montane region to another,or among lineages.In this study,we assessed patterns and drivers of avian diversity along an elevational gradient on the eastern slope of Mt.Gongga,the highest peak in the Hengduan Mountain Range in central China,and a mountain where comprehensive studies of avian diversity are still lacking.Methods:We surveyed bird species in eight 400-m elevational bands from 1200 to 4400 m a.s.l.between 2012 and 2017.To test the relationship between bird species richness and environmental factors,we examined the relative importance of seven ecological variables on breeding season distribution patterns:land area(LA),mean daily temperature(MDT),seasonal temperature range(STR),the mid-domain effect(MDE),seasonal precipitation(SP),invertebrate biomass(IB) and enhanced vegetation index(EVI).Climate data were obtained from five local meteorological stations and three temperature/relative humidity smart sensors in 2016.Results:A total of 219 bird species were recorded in the field,of which 204 were recorded during the breeding season(April–August).Species richness curves(calculated separately for total species,large-ranged species,and smallranged species) were all hump-shaped.Large-ranged species contributed more to the total species richness pattern than small-ranged species.EVI and IB were positively correlated with total species richness and small-ranged species richness.LA and MDT were positively correlated with small-ranged species richness,while STR and SP were negatively correlated with small-ranged species richness.MDE was positively correlated with large-ranged species richness.When we considered the combination of candidate factors using multiple regression models and model-averaging,total species richness and large-ranged species richness were correlated with STR(negative) and MDE(positive),while small-ranged species richness was correlated with STR(negative) and IB(positive).Conclusions:Although no single key factor or suite of factors could explain patterns of diversity,we found that MDE,IB and STR play important but varying roles in shaping the elevational richness patterns of different bird species categories.Model-averaging indicates that small-ranged species appear to be mostly influenced by IB,as opposed to large-ranged species,which exhibit patterns more consistent with the MDE model.Our data also indicate that the species richness varied between seasons,offering a promising direction for future work.
基金The National Natural Science Foundation of China, G1998040800 The Key Project for Basic Research on the Tibetan Plateau of CAS, No.KZ951-A1-204 No.KZ95T-06
文摘Based on biomass investigations, soil respiration an d plant photosynthesis measurement of dominant trees in Hailuogou valley o f Mt. Gongga, Southwest China, the carbon (C) storage, absorption and release for several typical woodlands in sub-alpine zones have been di scussed. For Abies fabri forest of 3,000 m above sea level, the C stor age amount is 177.4 t/ha for above-ground biomass and 143.2 t/ha for s oil below-ground biomass. The annual gross C fixed by vegetation photo synthesis is 20-24 t/ha. The C release by canopy respiration is 3.0-5.5 t/ha for arbors and 10-19 t/ha for surface soil and roots. The annual net C f ixed of forest ecosystem is about 6.0-7.1 t/ha. At lower elevations, t he amount of C released by woodlands is higher than that of woods a t higher elevations. The C fixed capacity of renewed forest with middle-aged t rees is higher than that of mature forest. Before becoming over-matured forest, woodland is an important sink of C whereas bareland in woods is the source of atmospheric C.
基金funded by the Natural Science Foundation of China(Grants Nos.41871069 and 42071084)Outstanding Youth Scholars Foundation of Sichuan Province(Grants No.2021JDJQ0009)。
文摘On 5th September 2022,a magnitude Ms-6.8 earthquake occurred nearby Mt.Gongga,western Sichuan.The stability of the glaciers in east Mt.Gongga close to the epicenter was widely concerned due to the strong shake triggered by the earthquake.Using multi-source observations(including in-situ photographs,remote sensing datasets before and after the event),we carried out a preliminary assessment of the stability and hazard risks of the Hailuogou(HLG)glacier.Triggered by the earthquake,a small block of fractured ice at the lowest part of icefall collapsed.The magnitude of the coseismic ice avalanche was relatively small,which is comparable in size to most ice avalanches over the past seven years,but much less than the previous mapped largest one(03 April 2018,runout~699 m).One most recent large(runout~608 m)ice avalanche occurred between 01 and 04 September,just before the earthquake,likely unloaded large amount of ice mass and made a larger ice avalanche avoided during the earthquake shake.Nevertheless,the momentum of collapsed snow-icerock mass could be safely unloaded over a wide and gentler-slope ice tongue area,limiting its mobility and the risk of a cascading hazard.Glacier-wide surface flow dynamics monitored by Sentinel-1 satellite SAR time series(12 September 2021–19 September 2022)show that HLG glacier velocity was generally consistent before and after the earthquake.The entire HLG glacier exhibited more stable than expected,with almost no abnormal features detected in its upper accumulation part,the lower ice tongue,and its lateral paraglacial slopes.Since the glacier valley has experienced remarkable downwasting and the paraglacial environment has been strongly disturbed and destabilized,we suggested that,to efficiently evaluate glacier-related cascading hazard risks,it is also necessary to systematically combine multi-source observations(e.g.,high-resolution UAV survey,radar/Lidar scan,ground investigation,monitoring and warning systems)to continuously monitor the regional glacier anomalies in the post-earthquake seismic active areas.
基金Major Directionality Program of the Chinese Academy of Sciences (KZCXZ-YW-317)Key Project of the National Natural Science Foundation of China (No. 90511007)+2 种基金National Basic Research Program of China (No. 2007CB411201)Innovative Research International Partnership Project of the Chinese Academy of Sciences (CXTD-Z2005-2)Project for Outstanding Young Scientists of the National Natural Science Foundation of China (No. 40121101).
文摘Great change, associated with global warming, has occurred at the Hailuogou （海螺沟） glacier, Mt. Gongga （贡嘎）, China, since the early 20th century. Various data indicate that the glacier has retreated 1 822 m in the past 106 years, with an annual mean retreat of 17.2 m, and the front elevation has risen by 300 m since 1823. Comparison of glacier variations and temperature fluctuations in China and the Northern Hemisphere, over the last 100 years, indicates that glacier retreat stages occurred during the warm phase, and vice versa. Mass balance records during 1959/60-2003/04 have shown that the glacier has suffered a constant mass loss of snow and ice. The accumulated mass balance, -10.83 m water equivalent, indicates an annual mean value of -0.24 m water equivalent. The correlation between the mass balance and temperature is significant, which also indicates that climate warming is the crucial cause of glacier loss. Local hydrological and climatic data demonstrate that runoff from the glacier has been increasing both seasonally and annually. The correlation analysis and trend analysis indicate that ice and snow melted water is the main cause of an increase in the runoff. As the climate has become warmer, changes in the glacier surface morphology have obviously occurred. These include a decrease in glacier thickness, enlargement of glacial caves, and reduction of the size of clefts on the glacier surface. The ablation period has lengthened and the ablation area has expanded. A variety of factors thus provide evidence that the Hailuogou glacier has suffered a rapid loss of snow and ice as a result of climatic warming.
基金supported by the National Natural Science Foundation of China(No.31772478,31501851)the Administration of the Gongga Mountain National Nature Reserve
文摘Background:Global climate change has had significant effects on animal distribution and population dynamics in mid-latitude alpine areas,but we know little about the basic ecology of high-altitude species due to the difficulties of conducting field research in the harsh climate and habitat present at high elevations.The Tibetan Snowcock(Tetraogallus tibetanus) is a little-known phasianid distributing in alpine areas at extremely high elevations in the mountains surrounding the Tibetan Plateau.Estimating the species occupancy rate and discussing the factors affecting its distribution based on infrared-triggered camera techniques would provide both a baseline to measure the influence of global warming and valuable information on its conservation and ecology.Methods:We used infrared-triggered cameras to investigate the Tibetan Snowcock on the western slope of Mt.Gongga from June to November 2016.We used the R package "overlap" to visualize its activity pattern,and used an occupancy model to both examine its habitat use as well as to determine the most influential variables affecting its habitat use.Results:Using 103 camera traps over 9213 camera-days,we recorded 428 instances of Tibetan Snowcock.The diel activity peaks of Tibetan Snowcock occurred during the periods of 8:00-10:00 am and 18:00-20:00 pm.The model estimate of occupancy for Tibetan Snowcock(0.830) was slightly higher than the na?ve site occupancy based on camera detections(0.663),indicating a wider use of habitat than the camera traps recorded.Elevation,slope,settlement density,road density,and EVI(enhanced vegetation index) were the most influential variables for its habitat use.Conclusions:The Tibetan Snowcock is confirmed to be diurnal.This species prefers an environment with a high elevation,gentle slope,and low EVI,apparently facing a trade-off between predator risk,foraging efficiency,and food availability.When human impact was low,there was a positive correlation between the habitat use of the Tibetan Snowcock and both its road and settlement densities.Infrared cameras and proper survey design are valuable for investigating extreme alpine phasianids.
