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Sap Flow of Populus euphratica in a desert Riparian Forest in an Extreme Arid Region During the Growing Season

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Journal of Integrative Plant Biology 2007年第4期49卷 425-436页

作者： Jian-Hua Si Qi Feng Xiao-You Zhang Zong-Qiang Chang Yong-Hong Su Hai-Yang Xi Cold and Arid Region Environmental and Engineering research Institute the Chinese Academy of Sciences Alashan desert eco-hydrology experimental research station Lanzhou 730000 China

In the present study, the heat pulse technique was applied to investigate the stem sap flow of Populus euphratica in a desert riparian forest in an extreme arid region from April to October 2003 and from May to October 2004. The experimental sites were in Qidaoqiao （101 °10′ E, 41°59′ N） and Bayantaolai farm （101°14′ E, 42°01′ N） in Ejina county, in the low reaches of the Heihe River, China. The results indicated that the diurnal change in the velocity of sap flow showed minor fluctuations. At night, the rising of sap flow could be observed in the main tree species because of root pressure. During the growing season, the maximum average velocity was observed in July, followed by August, and the same velocity was observed in September and May; the minimum velocity was observed in October. The transpiration from June to August during the growing season accounted for approximately 70% of the annual total transpiration. The sap flow velocity of P. euphratica trees of different ages could be arranged in the order： 15 yr 〉 25 yr 〉 50 yr. Sap flow velocity was closely related to changes in micrometeorological factors, with average sap flow velocity showing a significant linear correlation with net radiation, air temperature and relative humidity.

关键词： desert riparian forest extreme arid region heat-pulse technique Populus euphratica sap flow velocity.

Tree-ring-based reconstruction of temperature variability(1445–2011) for the upper reaches of the Heihe River Basin, Northwest China

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Journal of Arid Land 2016年第1期8卷 60-76页

作者： WANG Yamin FENG Qi KANG Xingcheng Alxa desert eco-hydrology experimental research station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences University of Chinese Academy of Sciences

Long-term temperature variability has significant effects on runoff into the upper reaches of inland rivers. This paper developed a tree-ring chronology of Qilian juniper (Sabina przewalskii Kom.) from the upper tree-line of the middle Qilian Mountains within the upper reaches of Heihe River Basin, Northwest China for a long-term reconstruction of temperature at the study site. In this paper, tree-ring chronology was used to examine climate-growth associations considering local climate data obtained from Qilian Meteorological station. The results showed that temperatures correlated extremely well with standardized growth indices of trees (r=0.564, Peconstructed and explained 57.8% of the inter-annual to decadal temperature variance at the regional scale for the period 1961–2011. Spatial correlation patterns revealed that reconstructed temperature data and gridded temperature data had a significant correlation on a regional scale, indicating that the reconstruction represents climatic variations for an extended area surrounding the sampling sites. Analysis of the temperature reconstruction indicated that major cold periods occurred during the periods of 1450s–1480s, 1590s–1770s, 1810s–1890s, 1920s–1940s, and 1960s–1970s. Warm intervals occurred during 1490s–1580s, 1780s–1800s, 1900s–1910s, 1950s, and 1980s to present. The coldest 100-year and decadal periods occurred from 1490s–1580s and 1780s–1800s, respectively, while the warmest 100 years within the studied time period was the 20th century. Colder events and intervals coincided with wet or moist conditions in and near the study region. The reconstructed temperature agreed well with other temperature series reconstructed across the surrounding areas, demonstrating that this reconstructed temperature could be used to evaluate regional clima

关键词： tree-ring climatic response temperature reconstruction upper reaches of Heihe River Basin

Vegetation characteristics and soil properties of artificially remediated grasslands:The case study of the Shimenhe mining area in Qilian Mountains,northwest China

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research in Cold and Arid Regions 2024年第4期16卷 190-200页

作者： XiaoMei Yang Qi Feng Meng Zhu Key Laboratory of ecohydrology of Inland River Basin Alax Desert Eco-hydrology Experimental Research StationQilian Mountains Eco-Environment Research Center in Gansu ProvinceNorthwest Institute of Eco-Environment and ResourcesChinese Academy of Sciences(CAS)LanzhouGansu 730000China

The mining of limestone mines plays a crucial role in societal and economic ***,mining activities have led to destructive variations in grassland ecology and soil,causing numerous environmental problems,and effective artificial restoration measures have been used to restore grasslands in the Shimenhe mining areas to different *** this study,we investigated,examined and analyzed plant community structure and its correlation with soil properties across varying degrees of alpine grassland restoration in Qilian Mountains Shimenhe restoration mines using the sample method,and studied the changes in species diversity using five diversity indexes(Simpson index,Shannon index,Margalef index,Dominance index and Evenness index).This study showed that the plant community characteristics with high recovered degree(HRD)> middle recovered degree(MRD)> low recovered degree(LRD)> very low recovered degree(VLRD),11 plant genera comprising 11 species across 10 families were *** families with robust ecological adaptability included Leguminosae,Rosaceae,Gramineae,Asteraceae,and *** highest Simpson,Shannon,Margalef and Evenness index of HRD grassland community species were 0.82,1.96,1.66 and 0.89,*** highest Dominance index of VLRD grassland community species was 0.34,which required several restoration methods such as spraying and *** pH and EC tended to decrease with increasing restoration,SOC,SMC,TP,AP,NH4-N,TN,AN and NO3-N tended to increase and the content of soil environmental factors contributed to vegetation growth across various restoration levels the mine *** conclusion,our study indicated that the community structure gradually diversified and soil properties changed positively with the increase of restoration degrees in the Qilian Mountains Shimenhe mine,and the best results of HRD restoration were *** study provides the theoretical basis for the restoration and conservation of grassland

关键词： Alpine mining area grassland Grassland ecosystem Mine restoration Plant characteristics Soil properties Qilian mountains

Comparable water use of two contrasting riparian forests in the lower Heihe River basin, Northwest China

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Journal of Forestry research 2018年第5期29卷 1215-1224页

作者： Tengfei Yu Qi Feng Jianhua Si Xiaoyou Zhang Haiyang Xi Chunyan Zhao Alxa desert eco-hydrology experimental research station Northwest Institute of Eco-Environment and ResourcesChinese Academy of Sciences Lanzhou 730000 China Key Laboratory of eco-hydrology of Inland River Basin Chinese Academy of Sciences Lanzhou 730000 China Gansu hydrology and Water Resources Engineering research Center Lanzhou 730000 China

Understanding forest ecosystem evapotranspiration（ET） is crucial for water-limited environments,particularly those that lack adequate quantified data such as the lower Heihe River basin of northwest China which is primarily dominated by Tamarix ramosissima *** Populus euphratica ***,we selected the growing season for 2 years （2012 and 2014） of two such forests under similar meteorological conditions to compare ET using the eddy covariance（EC） *** the growing seasons,daily ET of *** ranged from 0.3 to 8.0 mm day^（-1） with a mean of 3.6 mm day^（-1）,and daily ET of *** ranged from 0.9 to 7.9 mm day^（-1） with a mean of 4.6 mm day^（-1） for a total of 548 and 707 mm,*** significantly higher ET of the *** stand was directly linked to high soil evaporation rates under sufficient water availability from *** the soil evaporation was disregarded,water use was comparable to two contrasting riparian forests,a *** forest with a total transpiration of 465 mm and a *** forest with 473 *** analysis demonstrated that climate factors accounted for at least 80% of ET variation in both forest *** conclusion,water use of the riparian forests was low and comparable in this arid region,that suggest the long-term plant adaptation to the local climate and conditions of water availability.

关键词： Eddy covariance Evapotranspiration Heihe River basin Riparian forest

Non-growing season soil CO_2 efflux and its changes in an alpine meadow ecosystem of the Qilian Mountains,Northwest China

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Journal of Arid Land 2013年第4期5卷 488-499页

作者： ZongQiang CHANG XiaoQing LIU Qi FENG ZongXi CHE HaiYang XI YongHong SU JianHua SI Alashan desert eco-hydrology experimental research station Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences Gansu hydrology and Water Resources Engineering Center Academy of Water Resource Conservation Forests in Qilian Mountains of Gansu Province

Most soil respiration measurements are conducted during the growing *** tundra and boreal forest ecosystems,cumulative,non-growing season soil CO2 fluxes are reported to be a significant component of these systems＇ annual carbon ***,little information exists on soil CO2 efflux during the non-growing season from alpine ***,comparing measurements of soil respiration taken annually versus during the growing season will improve the accuracy of estimating ecosystem carbon budgets,as well as predicting the response of soil CO2 efflux to climate *** this study,we measured soil CO2 efflux and its spatial and temporal changes for different altitudes during the non-growing season in an alpine meadow located in the Qilian Mountains,Northwest *** experiments on the soil CO2 efflux of alpine meadow from the Qilian Mountains were conducted along an elevation gradient from October 2010 to April *** measured the soil CO2 efflux,and analyzed the effects of soil water content and soil temperature on this *** results show that soil CO2 efflux gradually decreased along the elevation gradient during the non-growing *** daily variation of soil CO2 efflux appeared as a single-peak *** soil CO2 efflux was low at night,with the lowest value occurring between 02：00-06：***,values started to rise rapidly between 07：00-08：30,and then descend again between 16：00-18：*** peak soil CO2 efflux appeared from 11：00 to 16：*** soil CO2 efflux values gradually decreased from October to February of the next year and started to increase in ***-growing season Q10 （the multiplier to the respiration rate for a 10℃ increase in temperature） was increased with raising altitude and average Q10 of the Qilian Mountains was generally higher than the average growing season Q10 of the Heihe River ***,non-growing season soil CO2 efflux was relatively high in October and early spring and low in the *** soil CO2

关键词： non-growing season soil CO2 efflux spatial and temporal variation alpine meadow Q10 values Qilian Mountains

Evapotranspiration of a Populus euphratica Oliv. forest and its controlling factors in the lower Heihe River Basin,Northwest China

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research in Cold and Arid Regions 2017年第2期9卷 175-182页

作者： TengFei Yu Qi Feng JianHua Si XiaoYou Zhang ChunYan Zhao alax desert eco-hydrology experimental research station Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Lanzhou Gansu 730000 China Key Laboratory of eco-hydrology of Inland River Basin Chinese Academy of Sciences Lanzhou Gansu 730000 China Gansu hydrology and Water Resources Engineering research Center Lanzhou Gansu 730000 China

Evapotranspiration (ET) within an ecosystem is crucial for die water-limited environment that currently lacks adequate quantification in the arid region of Northwest China, mainly covered by phreatophytes, such as the Populus euphratica Oliv. tree and the Tamarix ramosissima Ledeb. shrub species. Accordingly. ET was measured for an entire year using eddy covariance (EC) in P. euphratica stands in the lower Heihe River Basin, Northwest China. During the growing season, the total ET was 850 mm, with a mean of 4.0 mm/d, Which is obviously more than that observed at tree-level and stand level scales, which was likely due to the different level of soil evaporation induced by irrigation via water conveyance. Factors associated with ET fall into either environmental or plant eco-physiological categories. Environmental factors account for at least 79% variation of ET and the linear relationship between ET and the voundwater table (GWT) revealed the potential water use of P. euphratica forests under the non-water stress condition with die GWT less than 3 m deep. Plant eco-physiological parameters, specifically die leaf area 'index (LAI), have direct impact on the seasonal pattern of ET which provides a valuable reference to the wide-area estimates of ET for riparian forests by using LAI. In conclusion, P. euphratica forests have high water use after water conveyance, which may be the result of long-term adapting to local climates and limited water availability.

关键词： evapotranspiration eddy covariance Populus euphratica Oliv. forest Bei he River Basin

How changes of groundwater level affect the desert riparian forest ecosystem in the Ejina Oasis,Northwest China

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research in Cold and Arid Regions 2019年第1期11卷 62-80页

作者： HaiYang Xi JingTian Zhang Qi Feng Lu Zhang JianHua Si TengFei Yu Key Laboratory of ecohydrology of Inland River Basin Institute of Eco-Environment and Resources Chinese Academy of Sciences Alashan desert eco-hydrology experimental research station University of Chinese Academy of Sciences CSIRO Land and Water Flagship

Groundwater is a key factor controlling the growth of vegetation in desert riparian systems. It is important to recognise how groundwater changes affect the riparian forest ecosystem. This information will not only help us to understand the ecological and hydrological process of the riparian forest but also provide support for ecological recovery of riparian forests and water-resources management of arid inland river basins. This study aims to estimate the suitability of the Water Vegetation Energy and Solute Modelling(WAVES) model to simulate the Ejina desert riparian forest ecosystem changes,China, to assess effects of groundwater-depth change on the canopy leaf area index(LAI) and water budgets, and to ascertain the suitable groundwater depth for preserving the stability and structure of desert riparian forest. Results demonstrated that the WAVES model can simulate changes to ecological and hydrological processes. The annual mean water consumption of a Tamarix chinensis riparian forest was less than that of a Populus euphratica riparian forest, and the canopy LAI of the desert riparian forest should increase as groundwater depth decreases. Groundwater changes could significantly influence water budgets for T. chinensis and P. euphratica riparian forests and show the positive and negative effects on vegetation growth and water budgets of riparian forests. Maintaining the annual mean groundwater depth at around 1.7-2.7 m is critical for healthy riparian forest growth. This study highlights the importance of considering groundwater-change impacts on desert riparian vegetation and water-balance applications in ecological restoration and efficient water-resource management in the Heihe River Basin.

关键词： groundwater changes desert riparian forest Ejina Oasis WAVES leaf area index(LAI) water budgets

ecohydrological change mechanism of a rainfed revegetation ecosystem at southeastern edge of Tengger desert,Northwest China

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Science China Earth Sciences 2004年第Z1期47卷 71-77页

作者： XIAO Honglang CHENG Guodong LI Xinrong SONG Yaoxuan WANG Xinping Shapotou desert experimental research station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Shapotou Desert Experimental Research Station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Shapotou Desert Experimental Research Station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Shapotou Desert Experimental Research Station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Shapotou Desert Experimental Research Station Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

Study is made on a 45 km-long artificial ecosystem without irrigation in Tengger desert on the basis of long-term ecological monitoring and ecohydrological *** in water allocation, utilization, cycle and balance patterns in more than 40-year evolution of the soil-plant system are analyzed. The formation of a drought horizon in shrub rhizosphere and its effect, ecohydrological function of the crust and its effect on the soil-plant system change are discussed. Driven by water self-regulation and water stress, the soil-plant system is going to develop towards the steppe desert to ensure more effective use and optimum collocation of water resource.

关键词： ecohydrology, artificial ecosystem, soil-plant evolution, water balance, drought horizon, bio-crust, Chinese desert.

Effects of shrub species and microhabitats on dew formation in a revegetation-stabilized desert ecosystem in Shapotou, northern China

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Journal of Arid Land 2014年第4期6卷 389-399页

作者： YanXia PAN XinPing WANG Shapotou desert experimental research station Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences

Dew is an important supplement water source in arid and semi-arid areas. In order to determine the dew formation on different kinds of soils associated with various shrub species and microhabitats, we performed measurement of accumulated dew formation amount and duration in October 2009 in a revegetation-stabilized arid desert ecosystem in Shapotou area, northern China. The results indicated that the accumulated dew formation amount was four times larger at open spaces as compared to under the canopy, and it was nearly twice as much under living Artemisia ordosica plants（L.A.） as compared to under living Caragana korshinskii plants（L.C.）. The opposite characteristics were found for dew duration between different microhabitats. Dew amounts at different vertical heights around the shrub stands were in the order of 50 cm above the canopy〉the canopy edge〉under the canopy. Dew amount continued to increase after dawn, and the proportion of average accumulated dew amount after dawn accounting for the average maximum amount increased from above the canopy to under the canopy. Dew formation duration after sunrise accounted for more than 50% of the total formation duration during the day time. Contrary to the distribution characteristics of dew amount, dew duration after dawn and total dew formation duration during the day time were both highest under the canopy, followed by at the canopy edge and then at 50 cm above the canopy. The portion of dew duration after dawn accounting for the total dew duration during the day time increased from above the canopy to under the canopy. From these results, we may conclude that dew availability as a supplemental water resource for improving the microhabitats in water-limited arid ecosystems is position dependent especially for the plant microhabitats at different stands layers.

关键词： dew amount dew duration shrub species microhabitat soil surface type