In the context of ongoing climate change,rela-tionships between tree growth and climate present uncertain-ties,which limits the predictions of future forest dynamics.Northwest China is a region undergoing notable warm...In the context of ongoing climate change,rela-tionships between tree growth and climate present uncertain-ties,which limits the predictions of future forest dynamics.Northwest China is a region undergoing notable warming and increased precipitation;how forests in this region will respond to climate change has not been fully understood.We used dendrochronological methods to examine the rela-tionship between climate and the radial growth of four tree species in a riparian forest habitat in Altai region:European aspen(Populus tremula),bitter poplar(Populus laurifolia),Swedish birch(Betula pendula),and Siberian spruce(Picea obovata).The results reveal that European aspen was insen-sitive to climate changes.In contrast,bitter poplar showed a positive response to elevated temperatures and negative to increased moisture during the growing season.Swedish birch and Siberian spruce were adversely affected by higher temperatures but benefited from increased precipitation.A moving correlation analysis suggested that,against a back-drop of continuous warming,growth patterns of these spe-cies will diverge:European aspen will require close moni-toring,bitter poplar may likely to show accelerated growth,and the growth of Swedish birch and Siberian spruce may be inhibited,leading to a decline.These findings offer insight into the future dynamics of riparian forests under changing climate.展开更多
Using Landsat remote sensing images, we analyzed changes in each land use type and transitions among different land use types during land use and land cover change （LUCC） in Ningwu County, located in the eastern Loe...Using Landsat remote sensing images, we analyzed changes in each land use type and transitions among different land use types during land use and land cover change （LUCC） in Ningwu County, located in the eastern Loess Plateau of China, from 1990 to 2010. We found that grassland, woodland, and farmland were the main land use types in the study area, and the area of each type changed slightly from 1990 to 2010, whereas the area of water, construction land, and unused land increased greatly. For the whole area, the net change and total change were insignificant due to weak human activity intensity in most of the study area, and the LUCC was dominated by quasi-balanced two-way transitions from 1990 to 2010. The insignificant overall amount of LUCC appears to have resulted from offsetting of rapid increases in population, economic growth, and the im- plementation of a program to return farmland to woodland and grassland in 2000. This program converted more farmland into woodland and grassland from 2000 to 2010 than from 1990 to 2000, but reclamation of woodland and grassland for use as farmland continued from 2000 to 2010, and is a cause for concern to the local government.展开更多
To combat soil erosion and desertification,large-scale sandstorm control programs have been put in place since 2000 in the agro-pastoral transitional zone of northern China.Vegetation dynamics as well as soil wind ero...To combat soil erosion and desertification,large-scale sandstorm control programs have been put in place since 2000 in the agro-pastoral transitional zone of northern China.Vegetation dynamics as well as soil wind erosion control effects are very important for assessing the ecological success of sandstorm control programs in China.However,no comprehensive evaluation of vegetation dynamics and soil wind erosion control effects in this region has been achieved.In this study,we illustrate the vegetation and soil wind erosion dynamics of sandstorm control programs in the northern Shanxi Province using remote sensing data and soil wind erosion models.There was a significant increase in vegetation cover for 63.59% of the study area from 2001 to 2014 and a significant decrease for 2.00% of the study area.The normalized difference vegetation index (NDVI) showed that the largest increase occurred in autumn.Soil wind erosion mass decreased from 20.90 million tons in 2001 to 7.65 million tons in 2014.Compared with 2001,the soil wind erosion moduli were reduced by 43.05%,36.16%,and 62.66% in 2005,2010,and 2014,respectively.Spatially,soil wind erosion in most of the study area was alleviated between 2001 and 2014.The relationship between NDVI and soil wind erosion mass showed that the increased vegetation coverage reduced the soil wind erosion mass.In addition,wind was the main driving force behind the soil wind erosion dynamics.The results indicate that the vegetation coverage has increased and soil wind erosion mass has been reduced following the implementation of the sandstorm control programs.However,the ecological effects of the sandstorm control programs may vary over different periods.While the programs appear to be beneficial in the short term,there may be unintended consequences in the long term.Research on the sustainability of the ecological benefits of sandstorm control programs needs to be conducted in the future.展开更多
Retrospectively evaluating the efficacy of revegetation practices is helpful in planning and imple-menting future ecosystem restoration programs(ERP).Having a good understanding of how human activities can affect vege...Retrospectively evaluating the efficacy of revegetation practices is helpful in planning and imple-menting future ecosystem restoration programs(ERP).Having a good understanding of how human activities can affect vegetation cover,both before and after ERP,is particularly important in sandstorm hotspot areas.The Beijing-Tianjin Sandstorm Source Region(BTSSR)is one such area.We conducted an investigation into vegetation dynamics within the BTSSR.This was done using remote sensing data in conjunction with climate data sets and land use data spanning the 1982-2014 period.The relationships between climatic factors(such as precipitation and temperature),and vegetative change were modeled using a neural network method.By a process of residual analysis,the proportions of human-induced vegetative change both before and after the ERP were established.Our results show that:1)before the ERP(1982-2000),40.96%of the study area exhibited significantly progressive vegetation changes(p<0.05).This proportion decreased to encom-pass only 20.23%of the study area in the period following the ERP(2001-2014).2)89.55%of the study area showed signs of human-induced vegetation degradation before the ERP.Between 2001 and 2014 however,following ERP,this figure fell to only 27.78%.3)ERP implementation led to visible improvements in vegetative conditions within the BTSSR,especially in areas where ecological restoration measures were directly and anthropogenically applied.These results highlight the benefits that positive human action(i.e.,revegetation initiatives implemented under the framework of an ERP)have brought to the BTSSR.展开更多
基金supported by the Natural Science Foundation of Shanxi Province(202203021221008)the Special Funding for Shanxi Provincial Science and Technology Innovation Talent Team(202204051001010)the National Natural Science Foundation of China(41701047).
文摘In the context of ongoing climate change,rela-tionships between tree growth and climate present uncertain-ties,which limits the predictions of future forest dynamics.Northwest China is a region undergoing notable warming and increased precipitation;how forests in this region will respond to climate change has not been fully understood.We used dendrochronological methods to examine the rela-tionship between climate and the radial growth of four tree species in a riparian forest habitat in Altai region:European aspen(Populus tremula),bitter poplar(Populus laurifolia),Swedish birch(Betula pendula),and Siberian spruce(Picea obovata).The results reveal that European aspen was insen-sitive to climate changes.In contrast,bitter poplar showed a positive response to elevated temperatures and negative to increased moisture during the growing season.Swedish birch and Siberian spruce were adversely affected by higher temperatures but benefited from increased precipitation.A moving correlation analysis suggested that,against a back-drop of continuous warming,growth patterns of these spe-cies will diverge:European aspen will require close moni-toring,bitter poplar may likely to show accelerated growth,and the growth of Swedish birch and Siberian spruce may be inhibited,leading to a decline.These findings offer insight into the future dynamics of riparian forests under changing climate.
基金supported by the Open Fund Project of the Key Laboratory of Desert and Desertification, Chinese Academy of Sciences (No. KLDD-2014-001)the Important Specialized Science and Technology Item of Shanxi Province, China (No. 20121101011)the Natural Science Foundation of China (Nos. 41271513, 41271030)
文摘Using Landsat remote sensing images, we analyzed changes in each land use type and transitions among different land use types during land use and land cover change （LUCC） in Ningwu County, located in the eastern Loess Plateau of China, from 1990 to 2010. We found that grassland, woodland, and farmland were the main land use types in the study area, and the area of each type changed slightly from 1990 to 2010, whereas the area of water, construction land, and unused land increased greatly. For the whole area, the net change and total change were insignificant due to weak human activity intensity in most of the study area, and the LUCC was dominated by quasi-balanced two-way transitions from 1990 to 2010. The insignificant overall amount of LUCC appears to have resulted from offsetting of rapid increases in population, economic growth, and the im- plementation of a program to return farmland to woodland and grassland in 2000. This program converted more farmland into woodland and grassland from 2000 to 2010 than from 1990 to 2000, but reclamation of woodland and grassland for use as farmland continued from 2000 to 2010, and is a cause for concern to the local government.
基金the Natural Science Foundation of Shanxi Province (No.201701D221216)National Natural Science Foundation of China (Grant Nos.41401643 and 41475050).
文摘To combat soil erosion and desertification,large-scale sandstorm control programs have been put in place since 2000 in the agro-pastoral transitional zone of northern China.Vegetation dynamics as well as soil wind erosion control effects are very important for assessing the ecological success of sandstorm control programs in China.However,no comprehensive evaluation of vegetation dynamics and soil wind erosion control effects in this region has been achieved.In this study,we illustrate the vegetation and soil wind erosion dynamics of sandstorm control programs in the northern Shanxi Province using remote sensing data and soil wind erosion models.There was a significant increase in vegetation cover for 63.59% of the study area from 2001 to 2014 and a significant decrease for 2.00% of the study area.The normalized difference vegetation index (NDVI) showed that the largest increase occurred in autumn.Soil wind erosion mass decreased from 20.90 million tons in 2001 to 7.65 million tons in 2014.Compared with 2001,the soil wind erosion moduli were reduced by 43.05%,36.16%,and 62.66% in 2005,2010,and 2014,respectively.Spatially,soil wind erosion in most of the study area was alleviated between 2001 and 2014.The relationship between NDVI and soil wind erosion mass showed that the increased vegetation coverage reduced the soil wind erosion mass.In addition,wind was the main driving force behind the soil wind erosion dynamics.The results indicate that the vegetation coverage has increased and soil wind erosion mass has been reduced following the implementation of the sandstorm control programs.However,the ecological effects of the sandstorm control programs may vary over different periods.While the programs appear to be beneficial in the short term,there may be unintended consequences in the long term.Research on the sustainability of the ecological benefits of sandstorm control programs needs to be conducted in the future.
基金financial supports from the National Natural Science Foundation of China(Grant Nos.41977412,U1810101,and 41871193)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2020L0014)Higher Education Institution Project of Shanxi Province:Ecological Remediation of Soil Pollution Disciplines Group(No.20181401).
文摘Retrospectively evaluating the efficacy of revegetation practices is helpful in planning and imple-menting future ecosystem restoration programs(ERP).Having a good understanding of how human activities can affect vegetation cover,both before and after ERP,is particularly important in sandstorm hotspot areas.The Beijing-Tianjin Sandstorm Source Region(BTSSR)is one such area.We conducted an investigation into vegetation dynamics within the BTSSR.This was done using remote sensing data in conjunction with climate data sets and land use data spanning the 1982-2014 period.The relationships between climatic factors(such as precipitation and temperature),and vegetative change were modeled using a neural network method.By a process of residual analysis,the proportions of human-induced vegetative change both before and after the ERP were established.Our results show that:1)before the ERP(1982-2000),40.96%of the study area exhibited significantly progressive vegetation changes(p<0.05).This proportion decreased to encom-pass only 20.23%of the study area in the period following the ERP(2001-2014).2)89.55%of the study area showed signs of human-induced vegetation degradation before the ERP.Between 2001 and 2014 however,following ERP,this figure fell to only 27.78%.3)ERP implementation led to visible improvements in vegetative conditions within the BTSSR,especially in areas where ecological restoration measures were directly and anthropogenically applied.These results highlight the benefits that positive human action(i.e.,revegetation initiatives implemented under the framework of an ERP)have brought to the BTSSR.
