The Horqin Sandy Land（HSL）, the largest sandy land in the semi-arid agro-pastoral ecotone of Northeast China, has been subject to desertification during the past century. In response, and to control the desertificat...The Horqin Sandy Land（HSL）, the largest sandy land in the semi-arid agro-pastoral ecotone of Northeast China, has been subject to desertification during the past century. In response, and to control the desertification,government implemented the Three-North Shelter/Protective Forest Program, world＇s largest ecological reforestation/afforestation restoration program. The program began in1978 and will continue for 75 years until 2050. Understanding the dynamics of desertification and its driving forces is a precondition for controlling desertification.However, there is little evidence to directly link causal effects with desertification process（i.e., on the changing area of sandy land） because desertification is a complex process,that can be affected by vegetation（including vegetation cover and extent of shelter forests） and water factors such as precipitation, surface soil moisture, and evapotranspiration.The objectives of this study were to identify how influencing factors, especially shelter forests, affected desertification in HSL over a recent decade. We used Landsat TM imagery analysis and path analysis to identify the effects of spatiotemporal changes in water and vegetation parameters during2000–2010. Desertification was controlled during the study period, as indicated by a decrease in desert area at a rate of163.3 km2year-1and an increase in the area with reduced intensity or extent of desertification. Total vegetation cover in HSL increased by 10.6 % during the study period and this factor exerted the greatest direct and indirect effects on slowing desertification. The contribution of total vegetation cover to controlling desertification increased with the intensity of desertification. On slightly and extremely severe desertified areas, vegetation cover contributed 5 and 42 % of the desertification reduction, respectively. There were significant correlations between total vegetation cover and water conditions（i.e., evapotranspiration and precipitation）and the area of shelter forests（P ／ 0.0001）, in which water conditions and the existence of shelter forests contributed49.7 and 12.8 % to total vegetation cover, respectively. The area of shelter forests increased sharply due to program efforts, but only shrub forests had significant direct effects on reducing the area of desertification categorized as slightly desertified. The reason for the lack of direct effect of increased arbor forests（accounting for 95.3 % of the total increase in shelter forests） on reducing desertification might be that the selected arbor species were not suited to water conditions（low precipitation, high evapotranspiration） prevailing at HSL. The establishment of shelter forests aided control of desertification in the HSL region, but the effect was less than expected. Effective control of desertification in the HSL region or other similar sandy areas will require greater improvements in vegetation cover. In particular,shrub species should be selected for plantation with reference to their potential to survive and reproduce in the harsh climatic and weather conditions typical of desertified areas.展开更多
The Shelterbelt Forest System Program in northeast, north and northwest China （the Three-North Shelterbelt Program, TNSP） is the largest ecological reforestation program in the world. TNSP vegetation research has im...The Shelterbelt Forest System Program in northeast, north and northwest China （the Three-North Shelterbelt Program, TNSP） is the largest ecological reforestation program in the world. TNSP vegetation research has important ecological meaning and profound social and economic signiifcance. Here, spatio-temporal variation in vegetation cover under the TNSP was examined using the NDVI average method, major climatic factors such as temperature and precipitation, and linear regression trend analysis from 1982 to 2006. We found that in the past 25 years, NDVI vegetation in the study area has consistently risen at a rate of 0.007 per decade. Vegetation cover, temperature and precipitation are positively correlated. The area of vegetation associated with precipitation is larger than the area related to temperature;precipitation is the key factor affecting vegetation growth across the TNSP. From 1982 to 2006, regions with improved vegetation cover were found in the central and southern part of the Greater Khingan Mountains, central part of the Lesser Khingan Mountains, northeastern part of the Changbai Mountains, Yanshan Mountians, Western Liaoning Hilly Region, Altai Mountains, Tien Shan Mountains, eastern part of the Qilian Mountains, eastern part of the northwest desert as wel as southern part of the Gul y Region of the Loess Plateau. However, vegetation cover declined on both sides of the Greater Khingan Mountains, western part of the Hulun Buir Plateau, northern part of the Sanjiang Plain, southern part of Horqin Sandy Land, southern part of the northwest desert and northern part of the Gul y Region of the Loess Plateau.展开更多
三北防护林体系建设工程区(以下简称"三北工程区")早期的植被建设忽略了水资源承载力,对三北防护林的可持续维护产生了不利影响。为落实"以水定林草"的发展理念,在三个空间尺度上,基于1951—2018年降水量,采用Mann-...三北防护林体系建设工程区(以下简称"三北工程区")早期的植被建设忽略了水资源承载力,对三北防护林的可持续维护产生了不利影响。为落实"以水定林草"的发展理念,在三个空间尺度上,基于1951—2018年降水量,采用Mann-Kendall非参数检验方法、自回归积分滑动平均模型(Autoregressive Integrated Moving Average Model,ARIMA)和地理信息系统空间分析等方法,开展全年、生长季和非生长季降水量多尺度变化趋势与未来30年预测研究,结果表明:"三北工程区"全年和生长季降水量呈增长趋势的面积百分比分别为73.64%和70.10%,主要分布在西北荒漠区;非生长季降水量呈增长趋势的面积比例达92.06%,除黄土高原南部和风沙区的少部分地区而外,均呈增长趋势。全年、生长季和非生长季降水量呈增长趋势且置信度为90%以上的面积百分比分别为45.43%、37.31%和36.79%。18个重点建设区的雷达统计图显示:生长季与全年降水量的变化趋势一致,由东向西,松辽平原等7个区域以不显著减少趋势为主,松嫩平原等7个区域以不显著增长趋势为主,西部的柴达木盆地等4个区域以显著性达到90%或95%的增长趋势为主;非生长季除晋陕峡谷、泾河渭河流域以非显著减少趋势为主而外,其他地区均以增长趋势为主。5个"重点县"的降水统计量UFk与其反序统计量UBk两条曲线出现交点,表明年降水量有突变发生,库尔勒市、磴口县、科尔沁左翼后旗UFk与UBk曲线多处出现交点,表明年降水量突变发生频繁。采用ARIMA预测得出未来30年的年降水量,计算得到未来30年间的年降水量变化数据,并绘制其空间分布图。本研究可为三北工程区开展基于水资源承载能力的林草资源优化配置提供基础数据,为发展"雨养林草植被"提供科学支撑。展开更多
基金supported by grants from the National Nature Science Foundation of China(31025007)the Knowledge Innovation Program of the Chinese Academy of Sciences(KZCX1-YW-08-02)
文摘The Horqin Sandy Land（HSL）, the largest sandy land in the semi-arid agro-pastoral ecotone of Northeast China, has been subject to desertification during the past century. In response, and to control the desertification,government implemented the Three-North Shelter/Protective Forest Program, world＇s largest ecological reforestation/afforestation restoration program. The program began in1978 and will continue for 75 years until 2050. Understanding the dynamics of desertification and its driving forces is a precondition for controlling desertification.However, there is little evidence to directly link causal effects with desertification process（i.e., on the changing area of sandy land） because desertification is a complex process,that can be affected by vegetation（including vegetation cover and extent of shelter forests） and water factors such as precipitation, surface soil moisture, and evapotranspiration.The objectives of this study were to identify how influencing factors, especially shelter forests, affected desertification in HSL over a recent decade. We used Landsat TM imagery analysis and path analysis to identify the effects of spatiotemporal changes in water and vegetation parameters during2000–2010. Desertification was controlled during the study period, as indicated by a decrease in desert area at a rate of163.3 km2year-1and an increase in the area with reduced intensity or extent of desertification. Total vegetation cover in HSL increased by 10.6 % during the study period and this factor exerted the greatest direct and indirect effects on slowing desertification. The contribution of total vegetation cover to controlling desertification increased with the intensity of desertification. On slightly and extremely severe desertified areas, vegetation cover contributed 5 and 42 % of the desertification reduction, respectively. There were significant correlations between total vegetation cover and water conditions（i.e., evapotranspiration and precipitation）and the area of shelter forests（P ／ 0.0001）, in which water conditions and the existence of shelter forests contributed49.7 and 12.8 % to total vegetation cover, respectively. The area of shelter forests increased sharply due to program efforts, but only shrub forests had significant direct effects on reducing the area of desertification categorized as slightly desertified. The reason for the lack of direct effect of increased arbor forests（accounting for 95.3 % of the total increase in shelter forests） on reducing desertification might be that the selected arbor species were not suited to water conditions（low precipitation, high evapotranspiration） prevailing at HSL. The establishment of shelter forests aided control of desertification in the HSL region, but the effect was less than expected. Effective control of desertification in the HSL region or other similar sandy areas will require greater improvements in vegetation cover. In particular,shrub species should be selected for plantation with reference to their potential to survive and reproduce in the harsh climatic and weather conditions typical of desertified areas.
基金National Natural Science Foundation of China(4117111640961038)
文摘The Shelterbelt Forest System Program in northeast, north and northwest China （the Three-North Shelterbelt Program, TNSP） is the largest ecological reforestation program in the world. TNSP vegetation research has important ecological meaning and profound social and economic signiifcance. Here, spatio-temporal variation in vegetation cover under the TNSP was examined using the NDVI average method, major climatic factors such as temperature and precipitation, and linear regression trend analysis from 1982 to 2006. We found that in the past 25 years, NDVI vegetation in the study area has consistently risen at a rate of 0.007 per decade. Vegetation cover, temperature and precipitation are positively correlated. The area of vegetation associated with precipitation is larger than the area related to temperature;precipitation is the key factor affecting vegetation growth across the TNSP. From 1982 to 2006, regions with improved vegetation cover were found in the central and southern part of the Greater Khingan Mountains, central part of the Lesser Khingan Mountains, northeastern part of the Changbai Mountains, Yanshan Mountians, Western Liaoning Hilly Region, Altai Mountains, Tien Shan Mountains, eastern part of the Qilian Mountains, eastern part of the northwest desert as wel as southern part of the Gul y Region of the Loess Plateau. However, vegetation cover declined on both sides of the Greater Khingan Mountains, western part of the Hulun Buir Plateau, northern part of the Sanjiang Plain, southern part of Horqin Sandy Land, southern part of the northwest desert and northern part of the Gul y Region of the Loess Plateau.
文摘三北防护林体系建设工程区(以下简称"三北工程区")早期的植被建设忽略了水资源承载力,对三北防护林的可持续维护产生了不利影响。为落实"以水定林草"的发展理念,在三个空间尺度上,基于1951—2018年降水量,采用Mann-Kendall非参数检验方法、自回归积分滑动平均模型(Autoregressive Integrated Moving Average Model,ARIMA)和地理信息系统空间分析等方法,开展全年、生长季和非生长季降水量多尺度变化趋势与未来30年预测研究,结果表明:"三北工程区"全年和生长季降水量呈增长趋势的面积百分比分别为73.64%和70.10%,主要分布在西北荒漠区;非生长季降水量呈增长趋势的面积比例达92.06%,除黄土高原南部和风沙区的少部分地区而外,均呈增长趋势。全年、生长季和非生长季降水量呈增长趋势且置信度为90%以上的面积百分比分别为45.43%、37.31%和36.79%。18个重点建设区的雷达统计图显示:生长季与全年降水量的变化趋势一致,由东向西,松辽平原等7个区域以不显著减少趋势为主,松嫩平原等7个区域以不显著增长趋势为主,西部的柴达木盆地等4个区域以显著性达到90%或95%的增长趋势为主;非生长季除晋陕峡谷、泾河渭河流域以非显著减少趋势为主而外,其他地区均以增长趋势为主。5个"重点县"的降水统计量UFk与其反序统计量UBk两条曲线出现交点,表明年降水量有突变发生,库尔勒市、磴口县、科尔沁左翼后旗UFk与UBk曲线多处出现交点,表明年降水量突变发生频繁。采用ARIMA预测得出未来30年的年降水量,计算得到未来30年间的年降水量变化数据,并绘制其空间分布图。本研究可为三北工程区开展基于水资源承载能力的林草资源优化配置提供基础数据,为发展"雨养林草植被"提供科学支撑。
