基于MODIS NPP、EVI遥感影像,采用MVC法、一元线性回归法与Pearson相关分析法,探讨天山北坡昌吉州草地植被时空动态及其对同期气温、降水的响应。结果表明:2000—2020年,草地植被NPP、EVI均为跃动式显著递增,2016年后呈逐年递减;NPP、EV...基于MODIS NPP、EVI遥感影像,采用MVC法、一元线性回归法与Pearson相关分析法,探讨天山北坡昌吉州草地植被时空动态及其对同期气温、降水的响应。结果表明:2000—2020年,草地植被NPP、EVI均为跃动式显著递增,2016年后呈逐年递减;NPP、EVI多年均值为0.095 kg C·m^(-2)、0.186;相较于2000年(NPP=0.077 kg C·m^(-2)、EVI=0.166),2020年NPP(0.099 kg C·m^(-2))、EVI(0.194)分别增长了28.57%、16.87%。草地NPP空间异质性显著增加并呈扩大趋势,EVI空间差异逐年递增,变化范围分别为0.038 kg C·m^(-2)(NPP)、0.059(EVI)。在空间上,NPP、EVI多年平均分布具有差异;总体上,NPP、EVI随海拔升高而增加,但绿洲边缘、古尔班通古特沙漠南缘分布有高位EVI,面积占比65.01%的NPP与21.93%的EVI显著递增。9种草地类型植被NPP、EVI与降水呈显著正相关的面积占比远大于同期气温,不同类型草地对降水的响应具有差异。降水是草地植被的重要影响因子,但高海拔区域的适度增温有益于草地植被生长。展开更多
基于MOD17A3HGF NPP(Net primary productivity)与气温、降水量等数据,采用趋势分析与偏相关分析,在多个尺度(全疆、北疆与南疆、各地州市与11种草地类型)探讨了2000-2018年新疆天然草地NPP时空动态及其对气候变化的响应。结果表明:近2...基于MOD17A3HGF NPP(Net primary productivity)与气温、降水量等数据,采用趋势分析与偏相关分析,在多个尺度(全疆、北疆与南疆、各地州市与11种草地类型)探讨了2000-2018年新疆天然草地NPP时空动态及其对气候变化的响应。结果表明:近20 a新疆草地NPP呈波动递增,多年均值为0.103 kg C·m^(-2),由准噶尔西部山地、伊犁河谷、天山、阿尔泰山向准噶尔盆地、塔里木盆地逐渐降低;北疆草地多年平均NPP(0.149 kg C·m^(-2))高于南疆(0.055 kg C·m^(-2)),北疆、南疆草地NPP均表现为增加趋势;各地、州、市草地NPP总体为增加,但年际变化分异明显;11种天然草地类型(除高寒荒漠类)NPP表现为递增趋势,但不同草地类型存在差异。2000年后,新疆气候暖湿化有利于草地植被生长,但降水年际变化增强导致草地NPP年际波动剧烈。研究结果为新疆天然草地碳收支评估提供基础数据,能够促进天然草地健康评价以及可持续利用。展开更多
Drought-prone grasslands provide a critical resource for the millions of people who are dependent on livestock for food security.However,this ecosystem is potentially vulnerable to climate change(e.g.,precipitation)an...Drought-prone grasslands provide a critical resource for the millions of people who are dependent on livestock for food security.However,this ecosystem is potentially vulnerable to climate change(e.g.,precipitation)and human activity(e.g.,grazing).Despite this,the influences of precipitation and grazing on ecological functions of drought-prone grasslands in the Tianshan Mountains remain relatively unexplored.Therefore,we conducted a systematic field investigation and a clipping experiment(simulating different intensities of grazing)in a drought-prone grassland on the northern slopes of the Tianshan Mountains in China to examine the influences of precipitation and grazing on aboveground biomass(AGB),soil volumetric water content(SVWC),and precipitation use efficiency(PUE)during the period of 2014–2017.We obtained the meteorological and SVWC data using an HL20 Bowen ratio system and a PR2 soil profile hydrometer,respectively.We found that AGB was clearly affected by both the amount and seasonal pattern of precipitation,and that PUE may be relatively low in years with either low or excessive precipitation.The PUE values were generally higher in the rapid growing season(April–July)than in the entire growing season(April–October).Overall,moderate grazing can promote plant growth under water stress conditions.The SVWC value was higher in the clipped plots than in the unclipped plots in the rapid growing season(April–July),but it was lower in the clipped plots than in the unclipped plots in the slow growing season(August–October).Our findings can enhance the understanding of the ecological effects of precipitation and grazing in drought-prone grasslands and provide data that will support the effective local grassland management.展开更多
文摘基于MODIS NPP、EVI遥感影像,采用MVC法、一元线性回归法与Pearson相关分析法,探讨天山北坡昌吉州草地植被时空动态及其对同期气温、降水的响应。结果表明:2000—2020年,草地植被NPP、EVI均为跃动式显著递增,2016年后呈逐年递减;NPP、EVI多年均值为0.095 kg C·m^(-2)、0.186;相较于2000年(NPP=0.077 kg C·m^(-2)、EVI=0.166),2020年NPP(0.099 kg C·m^(-2))、EVI(0.194)分别增长了28.57%、16.87%。草地NPP空间异质性显著增加并呈扩大趋势,EVI空间差异逐年递增,变化范围分别为0.038 kg C·m^(-2)(NPP)、0.059(EVI)。在空间上,NPP、EVI多年平均分布具有差异;总体上,NPP、EVI随海拔升高而增加,但绿洲边缘、古尔班通古特沙漠南缘分布有高位EVI,面积占比65.01%的NPP与21.93%的EVI显著递增。9种草地类型植被NPP、EVI与降水呈显著正相关的面积占比远大于同期气温,不同类型草地对降水的响应具有差异。降水是草地植被的重要影响因子,但高海拔区域的适度增温有益于草地植被生长。
文摘基于MOD17A3HGF NPP(Net primary productivity)与气温、降水量等数据,采用趋势分析与偏相关分析,在多个尺度(全疆、北疆与南疆、各地州市与11种草地类型)探讨了2000-2018年新疆天然草地NPP时空动态及其对气候变化的响应。结果表明:近20 a新疆草地NPP呈波动递增,多年均值为0.103 kg C·m^(-2),由准噶尔西部山地、伊犁河谷、天山、阿尔泰山向准噶尔盆地、塔里木盆地逐渐降低;北疆草地多年平均NPP(0.149 kg C·m^(-2))高于南疆(0.055 kg C·m^(-2)),北疆、南疆草地NPP均表现为增加趋势;各地、州、市草地NPP总体为增加,但年际变化分异明显;11种天然草地类型(除高寒荒漠类)NPP表现为递增趋势,但不同草地类型存在差异。2000年后,新疆气候暖湿化有利于草地植被生长,但降水年际变化增强导致草地NPP年际波动剧烈。研究结果为新疆天然草地碳收支评估提供基础数据,能够促进天然草地健康评价以及可持续利用。
基金This research was funded by the Chinese Academy of Science(CAS)“Light of West China”Program(2018Title:“The effect of grazing on grassland productivity in the basin of Qinghai Lake”)+3 种基金the Key R&D and Transformation Projects in Qinghai Province of China(2018-SF-146)the Province Natural Foundation of Qinghai(2017-S-1-04,2020-ZJ-925)the Xinjiang Uygur Autonomous Region Grassland Ecological Restoration and Subsidy Monitoring Support Project(XJCYZZ202001)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0302).
文摘Drought-prone grasslands provide a critical resource for the millions of people who are dependent on livestock for food security.However,this ecosystem is potentially vulnerable to climate change(e.g.,precipitation)and human activity(e.g.,grazing).Despite this,the influences of precipitation and grazing on ecological functions of drought-prone grasslands in the Tianshan Mountains remain relatively unexplored.Therefore,we conducted a systematic field investigation and a clipping experiment(simulating different intensities of grazing)in a drought-prone grassland on the northern slopes of the Tianshan Mountains in China to examine the influences of precipitation and grazing on aboveground biomass(AGB),soil volumetric water content(SVWC),and precipitation use efficiency(PUE)during the period of 2014–2017.We obtained the meteorological and SVWC data using an HL20 Bowen ratio system and a PR2 soil profile hydrometer,respectively.We found that AGB was clearly affected by both the amount and seasonal pattern of precipitation,and that PUE may be relatively low in years with either low or excessive precipitation.The PUE values were generally higher in the rapid growing season(April–July)than in the entire growing season(April–October).Overall,moderate grazing can promote plant growth under water stress conditions.The SVWC value was higher in the clipped plots than in the unclipped plots in the rapid growing season(April–July),but it was lower in the clipped plots than in the unclipped plots in the slow growing season(August–October).Our findings can enhance the understanding of the ecological effects of precipitation and grazing in drought-prone grasslands and provide data that will support the effective local grassland management.
