High-elevation forests are among the most climate-sensitive ecosystems,and understanding their growth responses is crucial for predicting ecological consequences under future climate change.The climate sensitivity of ...High-elevation forests are among the most climate-sensitive ecosystems,and understanding their growth responses is crucial for predicting ecological consequences under future climate change.The climate sensitivity of tree species in the Hyrcanian forests in the Alborz Mountains of northern Iran,one of the southernmost temperate deciduous forests in the Northern Hemisphere,remains largely unexplored.In particular,Acer hyrcanum Fisch.&C.A.Mey.,growing mainly at high elevations,has not yet been studied in detail in dendroclimatology.Here,we present the first tree-ring chronology of Acer hyrcanum spanning 1814-2022 and analyze its growth-climate relationships to assess how this species reflects climatic sensitivity at the upper forest limit.The results reveal significant positive correlations between tree-ring width and temperature,particularly from May to September,suggesting that warmer growing-season temperatures enhance tree growth.In contrast,tree-ring width showed negative correlations with precipitation and standardized precipitation-evapotranspiration index,especially from January to May,and with cloud cover from March to May.These findings suggest that moisture availability does not limit radial growth in Acer hyrcanum and that the precipitation and water surplus signals may instead reflect the influence of cloud cover,which reduces sunlight availability during critical early-season months.This study contributes to the growing body of dendroclimatic research in the Alborz Mountains and,more broadly,on Acer species,particularly in high-elevation ecosystems where such studies are scarce.It also provides valuable insights into how Acer hyrcanum may respond to future climate change.展开更多
Adaptations to extreme environmental conditions are intriguing. Animal skin, which directly interacts with external environment, plays diverse and important roles in adaptive evolution. The thin and bare skin of amphi...Adaptations to extreme environmental conditions are intriguing. Animal skin, which directly interacts with external environment, plays diverse and important roles in adaptive evolution. The thin and bare skin of amphibians is sensitive to external environmental conditions and, thus, it facilitates investigations into adaptations for living in extreme environments. Herein, we compare the structures of skin in four anuran species living at elevations ranging from 100 m to 4500 m to assess phenotypic innovations in the skin of Nanorana parkeri, which lives at extremely high elevations. Analyses reveal similar basic skin structures, but N. parkeri differs from the other species by having more epidermal capillaries and granular glands, which correlate highly with responses to hypoxia and/or ultraviolet(UV) radiation. Further intraspecific comparisons from frogs taken at ~4500 m and ~2900 m reveal that all of the changes are fixed. Changes occurring only in the higher elevation population, such as possessing more skin pigments, may represent local adaptations to coldness and/or UV radiation. These results provide a morphological basis for understanding further the molecular adaptations of these frogs.展开更多
Understanding the process of adaptation is a key mission in modern evolutionary biology.Animals living at high elevations face challenges in energy meta bolism due to several environmental constraints(e.g., oxygen sup...Understanding the process of adaptation is a key mission in modern evolutionary biology.Animals living at high elevations face challenges in energy meta bolism due to several environmental constraints(e.g., oxygen supply, food availa bility,and movement time). Animal behavioral processes are intimately related to energy meta bolism, and therefore, behavioral modifica tions are expected to be an important mechanism for high-elevation adaptation. We tested this behavioral adaptation hypothesis using va ria tions of motion visual displays in toad-headed agamid lizards of the genus Phr ynocephalus. We predicted tha t complexity of visual motion displays would decrease with the increase of elevation, because motion visual displays are energetically costly. Displays of 12 Phr ynocephalus species were collected with elevations ranging from sea level to 4600 m. We quantified display complexity using the number of display components, display duration, pathways of display components, as well as display speed for each species. Association between display complexity and elevation was analyzed using the phylogenetic generalized least squares(PGLS)model. We found that both the number of display components and the average value of tail coil speed were negatively correlated with elevation, suggesting that toad-headed lizards living at high-elevation areas reduced their display complexity to cope with the environmental constraints. Our research provides direct evidence for high-elevation adaptation from a behavioral aspect and illustrates the potential impacts of environment heterogeneity on motion visual display diversification.展开更多
HSP90 AA1 is part of the heat shock protein 90 gene family and has important functions against heat stress. We report a case of molecular level parallel evolution of the HSP90 AA1 gene in high elevation amphibians. HS...HSP90 AA1 is part of the heat shock protein 90 gene family and has important functions against heat stress. We report a case of molecular level parallel evolution of the HSP90 AA1 gene in high elevation amphibians. HSP90 AA1 gene sequences of four high-elevation anurans, Bufo gargarizans, Nanorana parkeri, Rana kukunoris, and Scutiger boulengeri, were compared along with five of their low-elevation relatives. A total of 16 amino-acid sites were identified as parallel evolution between N. parkeri and R. kukunoris. We generated both model based（Zhang and Kumar＇s test） and empirical data based（parallel/divergence plotting） null distributions for non-parallel evolution, and both methods clearly determined that the observed number of parallel substitutions were significantly more than the null expectation. Furthermore, on the HSP90 AA1 gene tree, N. parkeri and R. kukunoris formed a strongly supported clade that was away from their respective relatives. This study provides a clear case of molecular parallel evolution, which may have significant implications in understanding the genetic mechanisms of high-elevation adaptation.展开更多
Climate change is generating range shifts in many organisms,notably along the elevational gradient in mountainous environments.However,moving up in elevation exposes organisms to lower oxygen availability,which may re...Climate change is generating range shifts in many organisms,notably along the elevational gradient in mountainous environments.However,moving up in elevation exposes organisms to lower oxygen availability,which may reduce the successful reproduction and development of oviparous organisms.To test this possibility in an upwardcolonizing species,we artificially incubated developing embryos of the viperine snake(Natrix maura)using a split-clutch design,in conditions of extreme high elevation(hypoxia at 2877 m above sea level;72%sea-level equivalent O2 availability)or low elevation(control group;i.e.normoxia at 436 m above sea level).Hatching success did not differ between the two treatments.Embryos developing at extreme high elevation had higher heart rates and hatched earlier,resulting in hatchlings that were smaller in body size and slower swimmers compared to their siblings incubated at lower elevation.Furthermore,post-hatching reciprocal transplant of juveniles showed that snakes which developed at extreme high elevation,when transferred back to low elevation,did not recover full performance compared to their siblings from the low elevation incubation treatment.These results suggest that incubation at extreme high elevation,including the effects of hypoxia,will not prevent oviparous ectotherms from producing viable young,but may pose significant physiological challenges on developing offspring in ovo.These early-life performance limitations imposed by extreme high elevation could have negative consequences on adult phenotypes,including on fitness-related traits.展开更多
aSoil degradation caused by soil erosion is one of the world's most critical environmental issues.Soil erosion in the Tianshan Mountains has caused various environmental problems in the surrounding areas.This stud...aSoil degradation caused by soil erosion is one of the world's most critical environmental issues.Soil erosion in the Tianshan Mountains has caused various environmental problems in the surrounding areas.This study used remote sensing data to analyze the distribution of the factors influencing soil erosion,and the revised universal soil loss equation(RUSLE)to calculate the total amount and distribution characteristics of soil erosion in the Tianshan Mountains in 2019.Due to the large error of RUSLE in soil erosion estimation in mountainous areas,this study modified RUSLE equation based on the characteristics of snow cover in the Tianshan Mountains.The results show that the average soil erosion was 1690.3 t/(km^(2)·year),of which insignificant erosion,slight erosion and moderate erosion accounted for 42,8%,22.4%and 9.9%,respectively.Severe erosion and above accounted for 13.3%.The accuracy of the soil erosion modulus calculated by the RUSLE was only 61.9%,with an average error of 1631.9 t/(km^(2)·year).The average error of the double-coefficient correction method was 1259.1 t/(km^(2)·year),and the average error of the modified formula method was reduced by 40.3%compared with the RUSLE,reaching 973.7 t/(km^(2)·year),and its accuracy reached 76.2%.Very severe erosion and catastrophic erosion are distributed on mountain ridges with higher elevation and on the northern area with higher precipitation.Snow cover has a certain inhibitory effect on soil erosion,and snow cover in alpine mountains is a factor that cannot be ignored in soil erosion research.展开更多
Environmental and spatial factors play important roles in generating and maintaining biodiversity.However,little is known about the main environmental and spatial correlates of multiple facets(taxonomic,functional and...Environmental and spatial factors play important roles in generating and maintaining biodiversity.However,little is known about the main environmental and spatial correlates of multiple facets(taxonomic,functional and phylogenetic)of freshwater communities at high altitudes,particularly in phytoplankton assemblages.We assessed the diversity patterns and structure of phytoplankton assemblages across the Qinghai Lake basin,a typical high-altitude region in the Qinghai-Tibet Plateau that encompasses Qinghai Lake(QL)and its inflowing tributaries(IT).We found that assemblage structure and diversity differed between the QL and IT in summer and autumn.QL sites supported higher algal density(dominated by cyanobacteria)than IT sites,which were domi-nated by diatoms.This contrasts with the historical dominance of diatoms in this lake and serves as an early warning of potential future algal blooms in this high-altitude biodiversity hotspot.Most taxonomic metrics were significantly higher in IT than in QL both seasons,whereas functional evenness,functional dispersion,taxonomic diversity and average taxonomic distinctness were higher in QL.This contrasting pattern likely results from lower competition pressures and more efficient resource use in lentic than in lotic waters.Environmental and spatial variables influencing phytoplankton assemblages varied among different diversity metrics,although environ-mental factors generally prevailed.However,the significant effect of spatial eigenvectors may also highlight the importance of mass effect on phytoplankton assemblages.This study clarifies our understanding of the patterns and main correlates of phytoplankton assemblages in a high-altitude lake,and has implications for future man-agement programs aimed at monitoring phytoplankton dynamics and assemblage trajectories in the Qinghai-Tibet Plateau and other extreme environments.展开更多
基金supported by the Alexander von Humboldt Foundation(AvH),which provided a research stay for HM(Humboldt-ID number 1222705).
文摘High-elevation forests are among the most climate-sensitive ecosystems,and understanding their growth responses is crucial for predicting ecological consequences under future climate change.The climate sensitivity of tree species in the Hyrcanian forests in the Alborz Mountains of northern Iran,one of the southernmost temperate deciduous forests in the Northern Hemisphere,remains largely unexplored.In particular,Acer hyrcanum Fisch.&C.A.Mey.,growing mainly at high elevations,has not yet been studied in detail in dendroclimatology.Here,we present the first tree-ring chronology of Acer hyrcanum spanning 1814-2022 and analyze its growth-climate relationships to assess how this species reflects climatic sensitivity at the upper forest limit.The results reveal significant positive correlations between tree-ring width and temperature,particularly from May to September,suggesting that warmer growing-season temperatures enhance tree growth.In contrast,tree-ring width showed negative correlations with precipitation and standardized precipitation-evapotranspiration index,especially from January to May,and with cloud cover from March to May.These findings suggest that moisture availability does not limit radial growth in Acer hyrcanum and that the precipitation and water surplus signals may instead reflect the influence of cloud cover,which reduces sunlight availability during critical early-season months.This study contributes to the growing body of dendroclimatic research in the Alborz Mountains and,more broadly,on Acer species,particularly in high-elevation ecosystems where such studies are scarce.It also provides valuable insights into how Acer hyrcanum may respond to future climate change.
基金supported by the National Natural Science Foundation of China Grant (31671326 and 31871275)supported by the Youth Innovation Promotion Association, Chinese Academy of Science, China
文摘Adaptations to extreme environmental conditions are intriguing. Animal skin, which directly interacts with external environment, plays diverse and important roles in adaptive evolution. The thin and bare skin of amphibians is sensitive to external environmental conditions and, thus, it facilitates investigations into adaptations for living in extreme environments. Herein, we compare the structures of skin in four anuran species living at elevations ranging from 100 m to 4500 m to assess phenotypic innovations in the skin of Nanorana parkeri, which lives at extremely high elevations. Analyses reveal similar basic skin structures, but N. parkeri differs from the other species by having more epidermal capillaries and granular glands, which correlate highly with responses to hypoxia and/or ultraviolet(UV) radiation. Further intraspecific comparisons from frogs taken at ~4500 m and ~2900 m reveal that all of the changes are fixed. Changes occurring only in the higher elevation population, such as possessing more skin pigments, may represent local adaptations to coldness and/or UV radiation. These results provide a morphological basis for understanding further the molecular adaptations of these frogs.
基金supported by grants from the National Natural Science Foundation of China(grant numbers:31872233,31572273)to Y.QI。
文摘Understanding the process of adaptation is a key mission in modern evolutionary biology.Animals living at high elevations face challenges in energy meta bolism due to several environmental constraints(e.g., oxygen supply, food availa bility,and movement time). Animal behavioral processes are intimately related to energy meta bolism, and therefore, behavioral modifica tions are expected to be an important mechanism for high-elevation adaptation. We tested this behavioral adaptation hypothesis using va ria tions of motion visual displays in toad-headed agamid lizards of the genus Phr ynocephalus. We predicted tha t complexity of visual motion displays would decrease with the increase of elevation, because motion visual displays are energetically costly. Displays of 12 Phr ynocephalus species were collected with elevations ranging from sea level to 4600 m. We quantified display complexity using the number of display components, display duration, pathways of display components, as well as display speed for each species. Association between display complexity and elevation was analyzed using the phylogenetic generalized least squares(PGLS)model. We found that both the number of display components and the average value of tail coil speed were negatively correlated with elevation, suggesting that toad-headed lizards living at high-elevation areas reduced their display complexity to cope with the environmental constraints. Our research provides direct evidence for high-elevation adaptation from a behavioral aspect and illustrates the potential impacts of environment heterogeneity on motion visual display diversification.
基金supported by the National Nature Science Foundation of China (grant number 31328021 to Jinzhong FU)NSERC of Canada (a discovery grant to Jinzhong FU)
文摘HSP90 AA1 is part of the heat shock protein 90 gene family and has important functions against heat stress. We report a case of molecular level parallel evolution of the HSP90 AA1 gene in high elevation amphibians. HSP90 AA1 gene sequences of four high-elevation anurans, Bufo gargarizans, Nanorana parkeri, Rana kukunoris, and Scutiger boulengeri, were compared along with five of their low-elevation relatives. A total of 16 amino-acid sites were identified as parallel evolution between N. parkeri and R. kukunoris. We generated both model based（Zhang and Kumar＇s test） and empirical data based（parallel/divergence plotting） null distributions for non-parallel evolution, and both methods clearly determined that the observed number of parallel substitutions were significantly more than the null expectation. Furthermore, on the HSP90 AA1 gene tree, N. parkeri and R. kukunoris formed a strongly supported clade that was away from their respective relatives. This study provides a clear case of molecular parallel evolution, which may have significant implications in understanding the genetic mechanisms of high-elevation adaptation.
基金the French Laboratory of Excellence project“TULIP”(ANR-10-LABX-41,ANR-11-IDEX-0002-02)INTERREG POCTEFA ECTOPYR(no.EFA031/15)+2 种基金the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 752299All experimental protocols(including animal collection,housing,experimentation,and release)were approved by the DREAL Midi-Pyrénées(Direction Régionale de l’Environnement,de l’Aménagement et du Logement)and by the Préfectures of Ariège,Aude,Haute-Garonne,Hautes-Pyrénées,and Pyrénées Orientales districts(ArrêtéPréfectoral No.2017-s-02 du 30 mars 2017)and ethical committee(APAFIS#16359-201808011445465 v4)All experiments were carried out in accordance with the approved guidelines.Animal caretakers and handlers were trained to use wildlife in scientific purposes(Decree No.2013-118 du 01 février 2013 and approval of the Ministry of Agriculture under No.I-75-MNHN-F1-15 du 17 juin 2015).
文摘Climate change is generating range shifts in many organisms,notably along the elevational gradient in mountainous environments.However,moving up in elevation exposes organisms to lower oxygen availability,which may reduce the successful reproduction and development of oviparous organisms.To test this possibility in an upwardcolonizing species,we artificially incubated developing embryos of the viperine snake(Natrix maura)using a split-clutch design,in conditions of extreme high elevation(hypoxia at 2877 m above sea level;72%sea-level equivalent O2 availability)or low elevation(control group;i.e.normoxia at 436 m above sea level).Hatching success did not differ between the two treatments.Embryos developing at extreme high elevation had higher heart rates and hatched earlier,resulting in hatchlings that were smaller in body size and slower swimmers compared to their siblings incubated at lower elevation.Furthermore,post-hatching reciprocal transplant of juveniles showed that snakes which developed at extreme high elevation,when transferred back to low elevation,did not recover full performance compared to their siblings from the low elevation incubation treatment.These results suggest that incubation at extreme high elevation,including the effects of hypoxia,will not prevent oviparous ectotherms from producing viable young,but may pose significant physiological challenges on developing offspring in ovo.These early-life performance limitations imposed by extreme high elevation could have negative consequences on adult phenotypes,including on fitness-related traits.
基金supported by the Third Xinjiang Scientific Expedition and Research Program (Grant No. 2022xjkk0602)National Cryosphere Desert Data Center (No. 2021kf02)Xinjiang Jiaotou’s Unveiling and Commanding System Project in 2021 (ZKXFWCG 2022060004)。
文摘aSoil degradation caused by soil erosion is one of the world's most critical environmental issues.Soil erosion in the Tianshan Mountains has caused various environmental problems in the surrounding areas.This study used remote sensing data to analyze the distribution of the factors influencing soil erosion,and the revised universal soil loss equation(RUSLE)to calculate the total amount and distribution characteristics of soil erosion in the Tianshan Mountains in 2019.Due to the large error of RUSLE in soil erosion estimation in mountainous areas,this study modified RUSLE equation based on the characteristics of snow cover in the Tianshan Mountains.The results show that the average soil erosion was 1690.3 t/(km^(2)·year),of which insignificant erosion,slight erosion and moderate erosion accounted for 42,8%,22.4%and 9.9%,respectively.Severe erosion and above accounted for 13.3%.The accuracy of the soil erosion modulus calculated by the RUSLE was only 61.9%,with an average error of 1631.9 t/(km^(2)·year).The average error of the double-coefficient correction method was 1259.1 t/(km^(2)·year),and the average error of the modified formula method was reduced by 40.3%compared with the RUSLE,reaching 973.7 t/(km^(2)·year),and its accuracy reached 76.2%.Very severe erosion and catastrophic erosion are distributed on mountain ridges with higher elevation and on the northern area with higher precipitation.Snow cover has a certain inhibitory effect on soil erosion,and snow cover in alpine mountains is a factor that cannot be ignored in soil erosion research.
基金supported by the National Natural Science Foundation of China(No.32371744).
文摘Environmental and spatial factors play important roles in generating and maintaining biodiversity.However,little is known about the main environmental and spatial correlates of multiple facets(taxonomic,functional and phylogenetic)of freshwater communities at high altitudes,particularly in phytoplankton assemblages.We assessed the diversity patterns and structure of phytoplankton assemblages across the Qinghai Lake basin,a typical high-altitude region in the Qinghai-Tibet Plateau that encompasses Qinghai Lake(QL)and its inflowing tributaries(IT).We found that assemblage structure and diversity differed between the QL and IT in summer and autumn.QL sites supported higher algal density(dominated by cyanobacteria)than IT sites,which were domi-nated by diatoms.This contrasts with the historical dominance of diatoms in this lake and serves as an early warning of potential future algal blooms in this high-altitude biodiversity hotspot.Most taxonomic metrics were significantly higher in IT than in QL both seasons,whereas functional evenness,functional dispersion,taxonomic diversity and average taxonomic distinctness were higher in QL.This contrasting pattern likely results from lower competition pressures and more efficient resource use in lentic than in lotic waters.Environmental and spatial variables influencing phytoplankton assemblages varied among different diversity metrics,although environ-mental factors generally prevailed.However,the significant effect of spatial eigenvectors may also highlight the importance of mass effect on phytoplankton assemblages.This study clarifies our understanding of the patterns and main correlates of phytoplankton assemblages in a high-altitude lake,and has implications for future man-agement programs aimed at monitoring phytoplankton dynamics and assemblage trajectories in the Qinghai-Tibet Plateau and other extreme environments.
