三北工程区植被恢复对土壤风蚀的影响及植被恢复潜力研究

三北地区是我国重要的生态屏障,分析2000—2019年三北防护林体系建设工程（简称：三北工程）区植被恢复时空变化状况,厘定人类活动与气候要素对植被恢复的贡献,探究植被恢复对土壤风蚀影响,评估植被恢复潜力空间,可为三北防护林体系建设工程未来规划管理和科学施策提供参考。本文在选取植被覆盖度和植被净初级生产力表征植被恢复状况基础上,利用地面数据,结合模型模拟,定量评估了2000—2019年三北防护林体系建设工程区植被恢复程度及其对土壤风蚀的影响,并对植被恢复潜力进行探究。研究结果表明：① 2000—2019年植被恢复程度高、较高的面积,占总面积的35.29%和13.16%,主要分布在黄土高原区及北部区域和风沙区与东北华北平原农区的部分地区。人类活动与气候因素对植被恢复贡献率为10.45%和89.55%;② 土壤风蚀以轻度侵蚀和微度侵蚀为主,呈逐年下降趋势,剧烈侵蚀面积减少了66.45%,防风固沙服务得到进一步提升。植被恢复程度与土壤风蚀模数呈负相关关系,植被恢复程度较好有助于降低土壤风蚀模数;③ 三北工程区森林、草地和荒漠生态系统仍有8.16%的恢复潜力,内蒙古高原北部部分地区、哈顺戈壁北部和准噶尔盆地西北部及周边区域、黄土高原南部部分区域存在较大恢复潜力。     

近30年来青海省三江源区草地的土壤侵蚀时空分析

分析了青海省三江源区草地生态系统土壤侵蚀的空间差异,以及草地退化与土壤侵蚀的关系,并对该区近30年来土壤侵蚀的动念变化进行描述.结果表明,该区域微度以上土壤侵蚀面积占源区总面积的46.47%,而草地生态系统发生微度以上土壤侵蚀的面积比例达56.04%.源区土壤侵蚀类型是以冻融侵蚀伴随着水力侵蚀或风力侵蚀的复合侵蚀为主,...     

三江源南部草地退化时空特征分析

本文利用三江源南部1977年MSS、1990年TM和2004年TM三期遥感影像,结合1∶10万地形图、1∶100万草地图、1∶100万植被图和野外考察等资料,分析该区草地退化的时空变化特征和规律。结果表明:该区草地总体呈轻度退化,即为轻度破碎化退化、轻度覆盖度下降、轻度破碎化和轻度覆盖度下降复合型退化,共占研究区退化总面积的84.3%;轻度退化草地主要散布在唐古拉山东北部区域,中度退化草地多数分布于河流、居民点周围,草地轻度沙化/盐化退化主要发生在湖盆周围、河岸附近、滩地等区域。草地退化面积随海拔高度升高近似于正态分布,退化面积集中4 400～5 300m左右。1977～1990年和1990～2004年前后两期草地退化面积占研究区草地面积12.6%和18.9%,指示着草地状况的恶化。同时,对前后两个时段比较发现,草地退化发生以破碎化为先导,随后发生覆盖度持续降低。沼泽和沼泽化草甸的变化反映了区内气候的趋干化。另外,受气候条件等因素的影响,前期草地和沼泽变化有转好迹象。     

青海湖流域植被盖度时空变化研究

高寒区植被变化一直是气候和生态学领域关注的热点问题。本研究基于MODIS NDVI数据计算的植被覆盖度数据和高分辨率气象数据,分析了青海湖流域2001-2017年植被覆盖度分布格局及动态变化,探讨了其对气候变化、人类活动和冻土退化的响应。结果表明：① 近十几年青海湖流域植被覆盖度整体表现为增加趋势,不同植被类型增幅存在差异性,草地增幅最大,达到6.1%/10a,其它植被类型增幅在2%~3%/10a之间;② 流域局部地区仍存在植被退化现象,研究期植被退化面积表现为先增加后减小的变化趋势。2006-2011年重度退化区集中在青海湖东岸,2011-2017年重度退化区集中在流域的西北部,这些区域是青海湖流域荒漠分布区,植被覆盖度较低,是今后生态恢复需重点关注的区域;③ 气候变化是流域植被覆盖度变化的主导因素,气候变化对青海湖流域主要植被类型覆盖度变化的贡献率为84.21%,对草原、草甸和灌丛植被覆盖度变化的贡献率分别为81.84%、87.47%和75.96%;④ 人类活动对流域主要植被类型覆盖度变化的贡献率为15.79%,对草原、草甸和灌丛植被覆盖度变化的贡献率分别为18.16%、12.53%和24.04%,环青海湖地区人类活动对植被恢复有促进效应,在青海湖流域北部部分地区人类活动的破坏力度仍大于建设力度;⑤ 冻土退化对青海湖流域草甸和灌丛植被覆盖度变化影响很小,主要影响草原植被覆盖度变化,冻土退化造成草原植被覆盖度增长速率减小了1.2%/10a。     

六盘水市土壤侵蚀时空特征及影响因素分析

六盘水市是我国生态地位极其重要,水土流失又较为严重的城市。近些年,六盘水市实施了一系列生态工程,为了定量分析六盘水市土壤侵蚀状况及其影响因素,本文基于RUSLE模型,利用降雨数据、遥感影像数据、土地利用数据等,对贵州省六盘水市1990-2015年土壤侵蚀模数和土壤侵蚀量进行定量模拟,分析其时空动态变化,利用地理探测器定量分析影响因素,并进行空间相关性分析,结果表明： ① 六盘水市土壤侵蚀以微度和中度侵蚀为主。土壤侵蚀严重地区主要分布在北盘江流域与南盘江流域交界处以及喀斯特山地地区,煤矿开采使植被覆盖等抑制土壤侵蚀因子减少作用,使局部地区土壤侵蚀程度加剧。② 1990-2010年平均土壤侵蚀模数整体为下降趋势,2010-2015年为上升趋势。其中2000年平均土壤侵蚀模数最大,2010年平均土壤侵蚀模数最小。该变化由降雨可蚀性因子和植被覆盖度因子综合影响所致。③ 植被覆盖度因子和多年平均降雨量因子是影响区域土壤侵蚀空间分布的重要因素。未利用土地、植被覆盖度小于0.3、坡度在25°以上和降雨量在1543~1593 mm之间的地区为高风险侵蚀区域。④ 植被覆盖度与土壤侵蚀在空间上全部呈负相关性,降雨因子与土壤侵蚀在空间上存在负相关性和正相关性。⑤ 土壤侵蚀改善区域大多分布在生态工程区域内,生态工程建设能够改善土壤侵蚀情况,不同生态工程保护侧重点不同导致土壤侵蚀改善程度不同。退耕还林还草工程对六盘水市土壤侵蚀的改善具有重要意义,六盘水市更宜退耕还林。     

中国北方典型农牧交错区的土壤风蚀危险度研究

土壤风蚀及其引发的土地退化、沙化和沙尘暴是中国北方严重的环境问题之一。通过定量评估中国北方典型农牧交错地区土壤风蚀危险程度,可以为区域生态环境的保护和生态修复提供科学支撑。本文基于文献调研、兼顾数据的可获得性,建立了包括风场强度、植被覆盖率、地形起伏度、土壤干燥度等因子在内的风蚀危险程度评价指标体系。同时,依据遥感参数反演和地面气象观测数据,在地理信息系统技术支持下,形成了上述因子的空间分布数据。另外,利用层次分析方法,构建土壤风蚀危险度评价模型,得到研究区土壤风蚀危险度的空间分布。最后,结合研究区土地利用数据,探讨了风蚀危险度空间分布格局的自然环境和土地利用背景。研究表明:研究区土壤风蚀极险型区域面积为1.47×10⁴km²,强险型区域面积为6.09×10⁴km²,危险型区域面积为3.47×10⁴km²,轻险型区域面积为3.45×10⁴km²,无险型区域面积为2.19×10⁴km²。本区土壤风蚀危险度呈现出从东南到西北逐渐增强的趋势,这与区域的植被、气候,以及土地利用的空间格局具有内在的有机联系。     

1975-2009年锡林郭勒盟东部地区草地退化态势及其空间格局分析

研究采用锡林郭勒盟东部3旗、市(东乌珠穆沁旗、西乌珠穆沁旗以及锡林浩特市)1975年MSS数据、1990,2000\2005年的Landsat TM数据,以及2009年的HJ-1等遥感影像,在分析研究区陆地植被覆盖与变化特点的基础上,建立了研究区草地变化遥感解译的分类系统,构建了锡林郭勒盟东部地区5期草地现状、4期草地...     

自然生态环境遥感动态监测与GIS分析评价——以山西“煤田之乡”的乡宁矿区为例

以1990、2000和2007年三期遥感影像为主体数据源,选取有"煤田之乡"称誉的山西省乡宁县作为实验区,采用遥感与GIS相结合的手段,在建立生态环境评价指标体系的基础上,利用生态环境状况指数(EI),对研究区生态环境进行监测与评价。结果表明:(1)1990-2007年,实验区耕地面积持续减少;林地面积先减少后增加,总体上显著增大;草地面积先增加后减少,总体呈减少趋势;建筑用地面积持续增加;未利用地面积先增加后减少,总体呈减少趋势。(2)1990-2007年,高植被覆盖地区面积先减少后增大,低植被覆盖地区面积持续减少,中度植被覆盖地区面积有所增加。(3)1990-2007年,轻度土壤侵蚀面积先增大后减小,总体面积变化不大;中度侵蚀面积先减小,后显著增大,总体呈增大趋势;重度侵蚀面积先增大,后显著减小,总体呈减小趋势。(4)1990-2000年,实验区生态环境状况明显变差;2000-2007年,生态环境状况显著变好;1990年到2007年生态环境状况略微变好,总体上先明显变差,后显著变好。     

基于NDVI的＂三江源区＂植被覆盖及分布状况分析

以“三江源”地区为研究对象，对该区遥感影像NDVI指数的提取，对植被盖度多级灰度分割，并通过野外的查证，对“三江源区”植被覆盖及其分布状况进行了系统的分析研究，为以后“三江源区”的草地分布状况以及其变化趋势的研究奠定了良好的基础。     

徐州市水土流失时空变化研究

本文以3S技术为支撑,在修正水土流失方程（RUSLE）的基础上,针对徐州黄泛平原-丘陵地带的特殊地形地貌、对2000年以来徐州市水土流失时空变化特征进行了分析。结果表明：2000-2014年徐州市土壤侵蚀等级以微度为主,微度侵蚀面积占总侵蚀面积多年平均达到76.34%;中度侵蚀次之,所占比例在10%~17%间;剧烈侵蚀所占比例最少。轻度及以上土壤侵蚀等级主要发生在中部微山湖下游、京杭大运河一带的丘陵岗地地区、主城区与故黄河北岸的黄泛平原地区,以及丰县、新沂、邳州的局部区域;土壤侵蚀存在一定程度年际变化特征,睢宁、丰县、邳州的部分地区侵蚀面积年际变化较为明显,土壤侵蚀总面积整体上呈现下降趋势。     

PREDICTION OF SEDIMENT REDUCING BENEFIT UNDER DIFFERENT RAINFALL CONDITIONS AND CONTROL DEGREES ON THE LOESS PLATEAU DEGREES ON THE LOESS PLATEAU

Soilerosionisoneofthemostseriousenvironmentalproblemsinthepresentworld.Itnotonlyrestrictstheproductionofagriculturebadly,butalsothreatensthenaturalenvironmentonwhichhumanbeinglive.Andthismakethemankindconfrontedwithtremendouschallenge.OntheLoessPlateau,soilandwaterlossisterrible,environmentisweak,anditshighsandyieldmakestheriverwayinthelowerreachesoftheHuanghe(Yellow)Riverfilledup,riverbeddrivenup,floodthreatprickedup,andresultsingreathiddentroublestothecontrollingoffloodandtherunningofirrig…     

Did Ecological Engineering Projects Have a Significant Effect on Large-scale Vegetation Restoration in Beijing-Tianjin Sand Source Region,China? A Remote Sensing Approach

Aiming for the restoration of degraded ecosystems, many ecological engineering projects have been implemented around the world. This study investigates the ecological engineering project effectiveness on vegetation restoration in the Beijing-Tianjin Sand Source Region(BTSSR) from 2000 to 2010 based on the rain use efficiency(RUE) trend in relation to the land cover. More than half of the BTSSR experienced a vegetation productivity increase from 2000 to 2010, with the increasing intensity being sensitive to the indicators chosen. A clear tendency towards smaller increasing areas was shown when using the net primary productivity(NPP, 51.30%) instead of the accumulated normalized difference vegetation index(59.30%). The short-term variation in the precipitation and intra-seasonal precipitation distribution had a great impact on the remote sensing-based vegetation productivity. However, the residual trends method(RESTREND) effectively eliminated this correlation, while incorporating the variance and skewness of the precipitation distribution increased the models′ ability to explain the vegetation productivity variation. The RUE combined with land cover dynamics was valid for the effectiveness assessment of the ecological engineering projects on vegetation restoration. Particularly, the result based on growing season accumulated normalized difference vegetation index(ΣNDVI) residuals was the most effective, showing that 47.39% of the BTSSR experienced vegetation restoration from 2000 to 2010. The effectiveness of the ecological engineering projects differed for each subarea and was proportional to the strength of ecological engineering. The water erosion region dominated by woodland showed the best restoration, followed by the wind-water erosion crisscross regions, while the wind erosion regions dominated by grassland showed the worst effect. Seriously degraded regions still cover more area in the BTSSR than restored regions. Therefore, more future effort should be put in restoring degraded land.     

Spatio-temporal variation of wind erosion in Inner Mongolia of China between 2001 and 2010

Using Geographic Information System(GIS), based on wind speed, precipitation, topographic, soil, vegetation coverage and land use data of Inner Mongolia between 2001 and 2010, we applied the revised wind erosion equation(RWEQ) model to simulate wind erosion intensity. The results showed that an area of approximately 47.8 × 10~4 km~2 experienced wind erosion in 2010, 23.2% of this erosion could be rated as severe, and 46.0% as moderate. Both the area and the intensity of wind erosion had decreased from 2001 to 2010, the wind erosion area reduced 10.1%, and wind erosion intensity decreased by 29.4%. Precipitation, wind speed, population size and urbanization in rural areas, and gross domestic product of primary industry(GDP1) were the main factors influencing wind erosion. Overall, these factors accounted for 88.8% of the wind erosion. These results indicated that the decrease in wind erosion over the past decade related to the increase in precipitation and the decrease in the number of windy days, while modest urban development and optimization of the economic structure might partially reduced the level of ecological pressure, highlighting the importance of human activities in controlling wind erosion.     

Soil Erosion and Vegetation Succession in Alpine Kobresia Steppe Meadow Caused by Plateau Pika A Case Study of Nagqu County, Tibet

This paper evaluated the impacts of mounds created by the plateau pika (Ochotona curzoniae) on the vege- tation composition, structure, and species diversity of an alpine Kobresia steppe meadow in Nagqu County, Tibet Autonomous Region, China. Based on mound height or the depth of erosion pit, we defined five stages of erosion and compared the floristic features of communities at these stages with those in undisturbed sites. In the study area, the mounds and pits covered up to 7% of the total area. Lancea tibetica, Lamiophlomis rotata, and Potentilla bifurca were the dominant species in erosion pits, and Kobresia pygmaea, the dominant species in undisturbed sites, became a com- panion species in eroded areas. In the process of erosion, the original vegetation was covered by soil ejected by the pika, then the mounds were gradually eroded by wind and rain, and finally erosion pits formed. The vegetation coverage in- creased with increasing erosion stages but remained significantly lower than that in undisturbed sites. Improved coverage eventually reduced soil erosion, and pit depth eventually stabilized at around 20cm. Aboveground biomass increased with increasing erosion stage, but the proportion of low-quality forage reached more than 94%. The richness index and Shannon-Wiener index increased significantly with increasing erosion stage, but the richness index in mound and pit areas was significantly lower than that in undisturbed sites.     

Spatial and temporal change patterns of freeze-thaw erosion in the three-river source region under the stress of climate warming

The three-river source region(TRSR), located in the Qinghai-Tibet Plateau in China, suffers from serious freeze-thaw(FT) erosion in China. Considering the unique eco-environment and the driving factors of the FT process in the TRSR, we introduce the driving force factors of FT erosion(rainfall erosivity and wind field intensity during FT period) and precipitation during the FT period(indicating the phase-changed water content). The objective was to establish an improved evaluation method of FT erosion in the TRSR. The method has good applicability in the study region with an overall precision of 92%. The spatial and temporal changes of FT erosion from 2000 to 2015 are analyzed. Results show that FT erosion is widely distributed in the TRSR, with slight and mild erosion being the most widely distributed, followed by moderate erosion. Among the three sub-regions, the source region of the Yellow River has the slightest erosion intensity, whereas the erosion intensity of the source region of Yangtze River is the most severe. A slight improvement can be observed in the condition of FTerosion over the whole study region from 2000 to 2015. Vegetation coverage is the dominant factor affecting the intensity of FT erosion in the zones with sparse vegetation or bare land, whereas the climate factors play an important role in high vegetation coverage area. Slopes28° also have a significant effect on the intensity of FT erosion in the zones. The results can provide a scientific basis for the prevention and management of the soil FT erosion in the TRSR.     

10年来锡林郭勒盟草原植被长势变化及其影响因子分析

对草原植被长势变化的监测,及其与气候因子关系的分析,对生态环境治理及保护具有重要意义。本文利用250m的MODIS-NDVI数据,构建草原植被长势指数(MGI),分析了16天间隔的植被长势变化及其与降水、气温的相关性和对降水响应的滞后性。得到锡盟3种草原类型区2001-2010年草原长势变化情况,及降水、气温在草原生长不同阶段对草原长势的影响。研究结果表明:(1)在空间上长势东部变化好于中部与西部,北部好于南部;时间上2003年长势最好、2001年长势最差。(2)锡盟内3种草原类型区MGI均与降水关系明显,与气温相关性不显著,降水对温性草原区长势变化的影响最大。(3)在草原生长的不同阶段,影响因子不同,前期与后期主要受气温影响,中期主要受降水影响,草原生长对降水存在明显的滞后,一般在32-48天,同时指出草原植被在不同时间段对降水响应的滞后时间。     

Comprehensive evaluation on agricultural environment in western China

Introduction Western China is vast in area with different landforms and ecosystems, and its environment is deteriorated with different agricultural productivities. The northwestern region is very drought for lack of rainfall, and desertification there is serious with difficulty in vegetation restoration, while in the southwestern region the land is fragile, vegetation is degraded and water and soil loss serious. Even worse, for the lack of effective management, new environmental problems deriv…