Background： Canopy structure, defined by leaf area index （LAI）, fractional vegetation cover （FCover） and fraction of absorbed photosynthetically active radiation （fAPAR）, regulates a wide range of forest functi...Background： Canopy structure, defined by leaf area index （LAI）, fractional vegetation cover （FCover） and fraction of absorbed photosynthetically active radiation （fAPAR）, regulates a wide range of forest functions and ecosystem services. Spatially consistent field-measurements of canopy structure are however lacking, particularly for the tropics. Methods： Here, we introduce the Global LAI database： a global dataset of field-based canopy structure measurements spanning tropical forests in four continents （Africa, Asia, Australia and the Americas）. We use these measurements to test for climate dependencies within and across continents, and to test for the potential of anthropogenic disturbance and forest protection to modulate those dependences. Results： Using data collected from 887 tropical forest plots, we show that maximum water deficit, defined across the most arid months of the year, is an important predictor of canopy structure, with all three canopy attributes declining significantly with increasing water deficit. Canopy attributes also increase with minimum temperature, and with the protection of forests according to both active （within protected areas） and passive measures （through topography）. Once protection and continent effects are accounted for, other anthropogenic measures （e.g. human population） do not improve the model. Conclusions： We conclude that canopy structure in the tropics is primarily a consequence of forest adaptation to the maximum water deficits historically experienced within a given region. Climate change, and in particular changes in drought regimes may thus affect forest structure and function, but forest protection may offer some resilience against this effect.展开更多
Background:Investigations of running gait among barefoot and populations have revealed a diversity of foot strike behaviors,with some preferentially employing a rearfoot strike(RFS) as the foot touches down while othe...Background:Investigations of running gait among barefoot and populations have revealed a diversity of foot strike behaviors,with some preferentially employing a rearfoot strike(RFS) as the foot touches down while others employ a midfoot strike(MFS) or forefoot strike(FFS).Here,we report foot strike behavior and joint angles among traditional Hadza hunter-gatherers living in Northern Tanzania.Methods:Hadza adults(n = 26) and juveniles(n = 14) ran at a range of speeds(adults:mean 3.4 ± 0.7 m/s,juveniles:mean 3.2 ± 0.5 m/s) over an outdoor trackway while being recorded via high-speed digital video.Foot strike type(RFS.MFS.or FFS) and hind limb segment angles at foot strike were recorded.Results:Hadza men preferentially employed MFS(86.7%of men),while Hadza women and juveniles preferentially employed RFS(90.9%and85.7%of women and juveniles,respectively).No FFS was recorded.Speed,the presence of footwear(sandals vs.barefoot),and trial duration had no effect on foot strike type.Conclusion:Unlike other habitually barefoot populations which prefer FFS while running.Hadza men preferred MFS.and Hadza women and juveniles preferred RFS.Sex and age differences in foot strike behavior among Hadza adults may reflect differences in running experience,with men learning to prefer MFS as they accumulate more running experience.展开更多
The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly...The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool assemblage.These two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C methods.They represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 ka.Our studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya Devu.The contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large scale.Combining new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans.展开更多
For decades,the so-called Peking Man(Homo erectus pekinensis)at Zhoukoudian has been considered to be a hominin that engaged in the controlled production and management of fire.However,relatively recent analyses have ...For decades,the so-called Peking Man(Homo erectus pekinensis)at Zhoukoudian has been considered to be a hominin that engaged in the controlled production and management of fire.However,relatively recent analyses have cast doubt on this assertion.The most compelling reason for this doubt was the absence of siliceous aggregates in the Zhoukoudian deposits.This study presents evidence establishing the controlled use of fire by Homo erectus pekinensis through analyses of four soil samples sourced from Layers 4 and 6 at Zhoukoudian Locality 1.These results demonstrate that all four specimens contain siliceous aggregates as well as elemental carbon,and the potassium content of the insoluble residues of these specimens ranges between 1.21%and 2.94%.The analyses provide strong evidence of the in situ use of fire by Homo erectus pekinensis.展开更多
Forensic taphonomy as a discipline requires standardization to satisfy Daubert criteria for sci-entific data to be admissible in court.In response,there has been a shift towards quantifica-tion of methodology and esti...Forensic taphonomy as a discipline requires standardization to satisfy Daubert criteria for sci-entific data to be admissible in court.In response,there has been a shift towards quantifica-tion of methodology and estimating the postmortem interval.Despite these advances,there are still biases and limitations within the discipline not explicitly addressed in the early stages of experimental design nor in final published works.In this article,unresolved debates with respect to the conductance and reporting of forensic taphonomic research are reviewed,beginning with the nature of experimental cadavers,human or animal analogues and their body size,and second,the forensic realism of experimental setups,specifically with respect to caging,clothing and number of carcases.Pigs,albeit imperfect,are a good model to gain a general idea of the trends that may be seen in humans in subsequent validation studies in facilities where human donors are available.To date,there is no consen-sus among taphonomists on the extent of the effect that body mass has on decomposition progression.More research is required with both human cadavers and non-human analogues that builds on our current knowledge of forensic taphonomy to answer these nagging questions.This will enable the discipline to make the reliable assumption that pigs and donor decomposition data can be applied to homicide cases.A suite of experimental design aspects is suggested to ensure systematic and standardized data collection across differ-ent biogeoclimatic circumstances to identify and quantify the effects of potential confounding variables.Such studies in multiple,varied biogeographic circumstances with standardized protocols,equipment and carrion will facilitate independent global validation of patterns.These factors are reviewed to show the need for adjustments in experimental design to ensure relevance and applicability of data within locally realistic forensic situations.The initiation of a global decomposition data network for forensic taphonomists is recommended.展开更多
Understanding the determinants of ranging patterns in species susceptible to habitat fragmentation is fundamental for assessing their long-term adaptability to an increasingly human-dominated landscape.The aim of this...Understanding the determinants of ranging patterns in species susceptible to habitat fragmentation is fundamental for assessing their long-term adaptability to an increasingly human-dominated landscape.The aim of this study was to determine and compare the influence of ground-based food availability,remotely sensed plant productivity,and indigenous forest use on the ranging patterns of the endangered samango monkey(Cercopithecus albogularis schwarzi).We collected monthly ranging data on two habituated samango monkey groups,from February 2012 to December 2016,from our field site in the Soutpansberg Mountains,South Africa.We used linear mixed models to explore how food availability,plant productivity,and indigenous forest use influenced monthly ranging patterns,while controlling for group size,number of sample days and day length.We found that as more areas of high plant productivity(derived from remotely sensed EVI)were incorporated into the ranging area,both total and core monthly ranging areas decreased.In addition,both total ranging area and mean monthly daily path length decreased as more indigenous forest was incorporated into the ranging area.However,we found no effect of either ground-based food availability or remotely sensed plant productivity on ranging patterns.Our findings demonstrate the behavioral flexibility in samango monkey ranging,as samangos can utilize matrix habitat during periods of low productivity but are ultimately dependent on access to indigenous forest patches.In addition,we highlight the potential of using remotely sensed areas of high plant productivity to predict ranging patterns in a small ranging,forest-dwelling guenon,over ground-based estimates of food availability.展开更多
The Xiaohe Cemetery archaeological site （Cal. 4-3.5 ka BP） is one of the most important Bronze Age sites in Xinjiang, China. Although the surrounding environment is an extremely arid desert now, abundant archaeologi...The Xiaohe Cemetery archaeological site （Cal. 4-3.5 ka BP） is one of the most important Bronze Age sites in Xinjiang, China. Although the surrounding environment is an extremely arid desert now, abundant archaeological remains indicate that human occupation was common during certain periods in the Holocene. Field investigations and laboratory analyses of a sediment profile near the Xiaohe Cemetery indicate that while the regional environment was arid desert throughout the Holocene there were three episodes of lake forma- tion near the site in the periods 4.8-3.5 ka BP, 2.6-2.1 ka BP and 1.2-0.9 ka BP. Geomorphic and hydrological investigations reveal that a lake or lakes formed in a low-lying area when water was derived initially from the Kongque River and then shunted into the Xiaohe River basin. Low amounts of active chemical elements in lacustrine sediment between 4.8-3.5 ka BP indicate abundant and continuous water volume in the lake; the content of active chemical elements increased between 2.6-2.1 ka BP but was still at a relatively low level, suggesting a declining amount of water and diminished inflow. Between 1.2-0.9 ka BP there was a very high content of active elements, suggesting decreased water volume and indicating that the lake was stagnate. In contrast, the general climate condition shows that there had a warm-humid stage at 8-6 ka BP, a cool-humid stage at 6-2.9 ka BP and a warm-dry stage at 2.9-0.9 ka BP in this region. The hydrological evolutions around Xiaohe Cemetery did not have one-to-one correspondence with climate changes. Regional comparison indicates that broad-scale climatic conditions played an important role through its influences on the water volume of the Tarim River and Kongque River. But, the formation of the lakes and their level were controlled by geomorphic conditions that influenced how much water volume could be shunted to Xiaohe River from Kongque River. Human occupation of the Xiaohe Cemetery and nearby regions during the Bronze Age and Han-Jin period （202 BC-420 AD） corresponded to the two earlier lake periods, while no human activities existed in the third lake period because of the decreased water volume.展开更多
基金supported by the‘Uncovering the variable roles of fire in savannah ecosystems’project,funded by Leverhulme Trust under grant IN-2014-022 and‘Resilience in East African Landscapes’project funded by European Commission Marie Curie Initial Training Network(FP7-PEOPLE-2013-ITN project number606879)funding from Australian Research Council,IUCN Sustain/African Wildlife Foundation and University of York Research Pump Priming Fund+1 种基金funding through the European Research Council ERC-2011-St G_20101109(project number 281986)and the British Ecological Society-Ecologists in Africa programmesupport through the‘Climate Change Impacts on Ecosystem Services and Food Security in Eastern Africa(CHIESA)’project(2011–2015),which was funded by the Ministry for Foreign Affairs of Finland,and coordinated by the International Centre of Insect Physiology and Ecology(icipe)in Nairobi,Kenya
文摘Background： Canopy structure, defined by leaf area index （LAI）, fractional vegetation cover （FCover） and fraction of absorbed photosynthetically active radiation （fAPAR）, regulates a wide range of forest functions and ecosystem services. Spatially consistent field-measurements of canopy structure are however lacking, particularly for the tropics. Methods： Here, we introduce the Global LAI database： a global dataset of field-based canopy structure measurements spanning tropical forests in four continents （Africa, Asia, Australia and the Americas）. We use these measurements to test for climate dependencies within and across continents, and to test for the potential of anthropogenic disturbance and forest protection to modulate those dependences. Results： Using data collected from 887 tropical forest plots, we show that maximum water deficit, defined across the most arid months of the year, is an important predictor of canopy structure, with all three canopy attributes declining significantly with increasing water deficit. Canopy attributes also increase with minimum temperature, and with the protection of forests according to both active （within protected areas） and passive measures （through topography）. Once protection and continent effects are accounted for, other anthropogenic measures （e.g. human population） do not improve the model. Conclusions： We conclude that canopy structure in the tropics is primarily a consequence of forest adaptation to the maximum water deficits historically experienced within a given region. Climate change, and in particular changes in drought regimes may thus affect forest structure and function, but forest protection may offer some resilience against this effect.
基金the National Science Foundation(BCS-0850815)Hunter College
文摘Background:Investigations of running gait among barefoot and populations have revealed a diversity of foot strike behaviors,with some preferentially employing a rearfoot strike(RFS) as the foot touches down while others employ a midfoot strike(MFS) or forefoot strike(FFS).Here,we report foot strike behavior and joint angles among traditional Hadza hunter-gatherers living in Northern Tanzania.Methods:Hadza adults(n = 26) and juveniles(n = 14) ran at a range of speeds(adults:mean 3.4 ± 0.7 m/s,juveniles:mean 3.2 ± 0.5 m/s) over an outdoor trackway while being recorded via high-speed digital video.Foot strike type(RFS.MFS.or FFS) and hind limb segment angles at foot strike were recorded.Results:Hadza men preferentially employed MFS(86.7%of men),while Hadza women and juveniles preferentially employed RFS(90.9%and85.7%of women and juveniles,respectively).No FFS was recorded.Speed,the presence of footwear(sandals vs.barefoot),and trial duration had no effect on foot strike type.Conclusion:Unlike other habitually barefoot populations which prefer FFS while running.Hadza men preferred MFS.and Hadza women and juveniles preferred RFS.Sex and age differences in foot strike behavior among Hadza adults may reflect differences in running experience,with men learning to prefer MFS as they accumulate more running experience.
基金supported by the National Natural Science Foundation of China(Grant Nos.41888101,41977380 and 42072033)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB26000000 and XDA2004010102)+3 种基金the Second Tibetan Plateau Scientific Expedition and Research(Grant No.2019QZKK0601)the National Social Science Foundation of China(Grant No.21@WTK001)supported by the Chinese Academy of Sciences President’s International Fellowship Initiative Award(Grant No.2018VCA0016)the Je Tsongkhapa Endowment for Central and Inner Asian Archaeology at the University of Arizona。
文摘The timing and mechanisms of the human occupation of the demanding high-altitude Tibetan Plateau environment are of great interest.Here,we report on our reinvestigations and dating of the Nwya Devu site,located nearly 4600 meters above sea level on the central Tibetan Plateau.A new microblade techno-complex was identified on a lower lake shore at this site,distinct from the previously reported blade tool assemblage.These two lithic assemblages were dated to 45.6±2.6 and10.3±0.5 ka using optically stimulated luminescence and accelerator mass spectrometry^(14)C methods.They represent,respectively,the earliest known Paleolithic and microlithic sites on the interior Tibetan Plateau,indicating multiple occupation episodes of hunter-gatherers during the past 45 ka.Our studies reveal that relatively stable depositional conditions and a paleoenvironment characterized by a comparatively warm climate facilitated these multiple occupations at Nwya Devu.The contemporaneous occurrence of the Upper Paleolithic blade technology on the Tibetan Plateau and most of Eurasia between 50 and 40 ka indicates rapid,large-scale dispersals of humans that profoundly affected human demography on a large scale.Combining new archaeological evidence and previously reported genetic data,we conclude that the Tibetan Plateau provided a relatively stable habitat for Upper Paleolithic hunter-gatherers,which may have contributed to the complex and multiple-origin gene pool of present-day Tibetans.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA05130202)was identified as a Major Basic Research Project of the Ministry of Science and Technology of China(2007FY110200)Support was also received from the State Administration of Work Safety
文摘For decades,the so-called Peking Man(Homo erectus pekinensis)at Zhoukoudian has been considered to be a hominin that engaged in the controlled production and management of fire.However,relatively recent analyses have cast doubt on this assertion.The most compelling reason for this doubt was the absence of siliceous aggregates in the Zhoukoudian deposits.This study presents evidence establishing the controlled use of fire by Homo erectus pekinensis through analyses of four soil samples sourced from Layers 4 and 6 at Zhoukoudian Locality 1.These results demonstrate that all four specimens contain siliceous aggregates as well as elemental carbon,and the potassium content of the insoluble residues of these specimens ranges between 1.21%and 2.94%.The analyses provide strong evidence of the in situ use of fire by Homo erectus pekinensis.
文摘Forensic taphonomy as a discipline requires standardization to satisfy Daubert criteria for sci-entific data to be admissible in court.In response,there has been a shift towards quantifica-tion of methodology and estimating the postmortem interval.Despite these advances,there are still biases and limitations within the discipline not explicitly addressed in the early stages of experimental design nor in final published works.In this article,unresolved debates with respect to the conductance and reporting of forensic taphonomic research are reviewed,beginning with the nature of experimental cadavers,human or animal analogues and their body size,and second,the forensic realism of experimental setups,specifically with respect to caging,clothing and number of carcases.Pigs,albeit imperfect,are a good model to gain a general idea of the trends that may be seen in humans in subsequent validation studies in facilities where human donors are available.To date,there is no consen-sus among taphonomists on the extent of the effect that body mass has on decomposition progression.More research is required with both human cadavers and non-human analogues that builds on our current knowledge of forensic taphonomy to answer these nagging questions.This will enable the discipline to make the reliable assumption that pigs and donor decomposition data can be applied to homicide cases.A suite of experimental design aspects is suggested to ensure systematic and standardized data collection across differ-ent biogeoclimatic circumstances to identify and quantify the effects of potential confounding variables.Such studies in multiple,varied biogeographic circumstances with standardized protocols,equipment and carrion will facilitate independent global validation of patterns.These factors are reviewed to show the need for adjustments in experimental design to ensure relevance and applicability of data within locally realistic forensic situations.The initiation of a global decomposition data network for forensic taphonomists is recommended.
文摘Understanding the determinants of ranging patterns in species susceptible to habitat fragmentation is fundamental for assessing their long-term adaptability to an increasingly human-dominated landscape.The aim of this study was to determine and compare the influence of ground-based food availability,remotely sensed plant productivity,and indigenous forest use on the ranging patterns of the endangered samango monkey(Cercopithecus albogularis schwarzi).We collected monthly ranging data on two habituated samango monkey groups,from February 2012 to December 2016,from our field site in the Soutpansberg Mountains,South Africa.We used linear mixed models to explore how food availability,plant productivity,and indigenous forest use influenced monthly ranging patterns,while controlling for group size,number of sample days and day length.We found that as more areas of high plant productivity(derived from remotely sensed EVI)were incorporated into the ranging area,both total and core monthly ranging areas decreased.In addition,both total ranging area and mean monthly daily path length decreased as more indigenous forest was incorporated into the ranging area.However,we found no effect of either ground-based food availability or remotely sensed plant productivity on ranging patterns.Our findings demonstrate the behavioral flexibility in samango monkey ranging,as samangos can utilize matrix habitat during periods of low productivity but are ultimately dependent on access to indigenous forest patches.In addition,we highlight the potential of using remotely sensed areas of high plant productivity to predict ranging patterns in a small ranging,forest-dwelling guenon,over ground-based estimates of food availability.
基金Major Program of National Social Science Foundation of China, No.11＆ZD183 National Key Project of Scientific and Technical Supporting Program of China, No.2013BAK08B02 National Natural Science Foundation of China, No.41171006
文摘The Xiaohe Cemetery archaeological site （Cal. 4-3.5 ka BP） is one of the most important Bronze Age sites in Xinjiang, China. Although the surrounding environment is an extremely arid desert now, abundant archaeological remains indicate that human occupation was common during certain periods in the Holocene. Field investigations and laboratory analyses of a sediment profile near the Xiaohe Cemetery indicate that while the regional environment was arid desert throughout the Holocene there were three episodes of lake forma- tion near the site in the periods 4.8-3.5 ka BP, 2.6-2.1 ka BP and 1.2-0.9 ka BP. Geomorphic and hydrological investigations reveal that a lake or lakes formed in a low-lying area when water was derived initially from the Kongque River and then shunted into the Xiaohe River basin. Low amounts of active chemical elements in lacustrine sediment between 4.8-3.5 ka BP indicate abundant and continuous water volume in the lake; the content of active chemical elements increased between 2.6-2.1 ka BP but was still at a relatively low level, suggesting a declining amount of water and diminished inflow. Between 1.2-0.9 ka BP there was a very high content of active elements, suggesting decreased water volume and indicating that the lake was stagnate. In contrast, the general climate condition shows that there had a warm-humid stage at 8-6 ka BP, a cool-humid stage at 6-2.9 ka BP and a warm-dry stage at 2.9-0.9 ka BP in this region. The hydrological evolutions around Xiaohe Cemetery did not have one-to-one correspondence with climate changes. Regional comparison indicates that broad-scale climatic conditions played an important role through its influences on the water volume of the Tarim River and Kongque River. But, the formation of the lakes and their level were controlled by geomorphic conditions that influenced how much water volume could be shunted to Xiaohe River from Kongque River. Human occupation of the Xiaohe Cemetery and nearby regions during the Bronze Age and Han-Jin period （202 BC-420 AD） corresponded to the two earlier lake periods, while no human activities existed in the third lake period because of the decreased water volume.
