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Changes in morphology and soil nutrient patterns of nebkhas in arid regions along a precipitation gradient

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research in cold and arid regions 2021年第3期13卷 256-267页

作者： WeiCheng Luo wenzhi zhao bing liu Heng Ren linze inland river basin research station Chinese Ecosystem Research NetworkKey Laboratory of Ecohydrology of Inland River BasinNorthwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China

Nebkhas, discrete mounds of sand and vegetation, are a common landscape feature critical to the stability of desert ecosystems and supported by limited precipitation. Nebkha morphology and spatial pattern vary in landscapes, but it is unclear how they change along precipitation gradients in arid and semi-arid regions. In this study we determined morphology and soil nutrient patterns of nebkha from different regions of northwestern china. The objective of this study was to understand zonal differences among nebkhas and how morphological characteristics and soil nutrient patterns of nebkha change along a precipitation gradient in northwestern china. Our results shows that mean annual precipitation(MAP) had significant effects on morphological characteristics of nebkhas such as height, area, and volume which significantly decreased with an increase in MAP. MAP had significant positive effects on shrub cover and species richness of nebkha. Soil nutrients such as soil organic matter(SOM), total carbon(TC), total nitrogen(TN), and total phosphorus(TP) in the 0-10 cm layer increased with an increase of MAP, and soil nutrient content within nebkhas was higher than in inter-nebkha *** concluded that nebkhas are "fertile islands" with an important role in ecosystem dynamics in study regions. Further,MAP is a key factor which determined zonal differences, morphological, and soil nutrients patterns of nebkhas. However,disturbance, such as animal grazing, and planted sand-stabilizing vegetation accelerated the degeneration of nebkha landscapes. We recommend implementation of protective measures for nebkhas in arid and semi-arid areas of china.

关键词： Nebkha morphology soil nutrient precipitation gradient arid and semi-arid lands

Assessing spatial and temporal variability in waterconsumption and the maintainability oasis maximumarea in an oasis region of Northwestern china

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research in cold and arid regions 2020年第4期12卷 217-233页

作者： XueXiang Chang wenzhi zhao XueLi Chang bing liu Jun Du Northwest institute of eco-Environment and Resources Chinese Academy of SciencesLinze Inland River Basin Research StationKey Laboratory of Ecohydrology of Inland River BasinCASLanzhouGansu 730000China School of Natural Resources and environmental engineering Ludong UniversityYantaiShandong 264025China

Water consumption is a key role in improving the efficiency and sustainability of water management in arid *** this study, we explored an approach based on meta-analysis, MODIS NDVI products, land-use spatial distribution, andsoil water physical parameters to gain insight into long-term and large scale distribution of land use and water consumption,maintain maximum Zhangye Oasis area according to heihe river runoff, and suitable water resource management inZhangye Oasis. This approach was initiated in order to improve the efficiency of irrigation and water resource managementin arid regions. Results showed that heihe river runoff can maintain a maximum Zhangye Oasis area of 22.49×104 *** the 2000−2016 growing seasons, actual oasis water consumption ranged from 11.35×108 m3 to 13.73×108 m3, witha mean of (12.89 ± 0.60)×108 m3;if maintaining agricultural production and oasis stability was chosen, oasis water consumptionranged from 10.24×108 m3 to 12.37×108 m3, with a mean of (11.62 ± 0.53)×108 m3. From the perspective of waterresources management and ecosystem stability, it is necessary to reduce the area of Zhangye Oasis or choose the minimumwater consumption method to manage the oasis, to ease the pressure of water shortage and maintain stable and sustainabledevelopment of the Zhangye Oasis. These results can provide future practical guidance for water resource management ofcoordinated development of the economy and the environment in an arid area.

关键词： meta-analysis water consumption land-use spatial and temporal distribution runoff Northwestern china

Effects of shrub presence and shrub species on ground beetle assemblages (Carabidae,Curculionidae and Tenebrionidae) in a sandy desert,northwestern china

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Journal of arid Land 2015年第1期7卷 110-121页

作者： JiLiang liu wenzhi zhao FengRui LI linze inland river basin research station Chinese Ecosystem Research Network laboratory of ecohydrology and Integrated river basin science Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences

Shrub presence has an important effect on the structuring of ground beetles in desert ecosystems. In this study, in order to determine how shrubs and different species influence ground beetle assemblages in a sandy desert scrubland dominated by two different shrub species, namely Calligonum mongolicum and Nitraria sphaerocarpa, we sampled the ground beetles using pitfall traps during spring, summer and autumn in 2012. At the community level, the activity density of the ground beetles was shown to be significantly higher under shrubs than in intershrub bare habitats in spring; but an opposite pattern occurred in autumn, suggesting the presence of sea- son-specific shrub effects on the activity density of the ground beetles. Meanwhile, at the trophic group level, the activity density and species richness of predators were significantly greater under shrubs than in intershrub bare habitats in spring, whereas an opposite trend occurred on the activity density in autumn. N. sphaerocarpa shrubs had a positive effect on the activity density of herbivores in the three seasons, and C. mongolicum shrubs had a positive effect on the activity density of detritivores in spring and autumn. At the species level, more Microdera sp. was captured under shrubs than in intershrub bare habitats in spring. During the same time, we also found that C. mongolicum shrubs had a positive effect on Blaps gobiensis in spring, Carabus sp. in autumn, and Tentyria sp. in spring and autumn, and N. sphaerocarpa shrubs had a positive effect on Cyphogenia chinensis, Sternoplax setosa in spring and summer, and Curculionidae sp. 1 in summer and autumn. The study results suggest that shrub presence, shrub species and season variation are important factors for ground beetle assemblages in this desert ecosystem, but the responses of beetles differed among trophic and taxonomic levels.

关键词： Calligonum mongolicum Nitraria sphaerocarpa ground beetle assemblages sandy desert ecosystem heihe river basin

Biodiversity, productivity, and temporal stability in a natural grassland ecosystem of china

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research in cold and arid regions 2018年第4期10卷 293-304页

作者： bing liu wenzhi zhao YangYang Meng Chan liu linze inland river basin research station Key Laboratory of Ecohydrology of Inland River Basin Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences

Understanding the effect of biodiversity on ecosystem function is critical to promoting the sustainability of ecosystems and species conservation in natural ecosystems. We observed species composition, species richness and aboveground biomass,and simulated the competitive assemblages in a natural grassland ecosystem of china, aiming to test some assumptions and predictions about biodiversity–stability relationships. Our results show that aboveground productivity and temporal stability increased significantly with increasing species richness, and via a combination of overyielding, species asynchrony, and portfolio effects. Species interactions resulted in overyielding caused by trait-independent complementarity, and were not offset by a negative dominance effect and trait-dependent complementarity effect. Therefore, the mechanisms underlying the biodiversity effect shifted from the selection effect to the complementarity effect as diversity increased, and both effects were coexisted but the complementarity effect represent a mechanism that facilitates long term species coexistence in a natural grassland ecosystem of china.

关键词： biodiversity productivity temporal stability overyielding effect species interactions complementarity effect selection effect

Evapotranspiration of an oasis-desert transition zone in the middle stream of heihe river, Northwest china

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Journal of arid Land 2014年第5期6卷 529-539页

作者： LiWen zhao wenzhi zhao linze inland river basin research station Chinese Ecosystem Network Research Key laboratory of ecohydrology of inland river basin Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences

As a main component in water balance, evapotranspiration is of great importance for water saving and irrigation-measure making, especially in arid or semiarid regions. Although studies of evapotranspiration have been conducted for a long time, studies concentrated on oasis-desert transition zone are very limited. On the basis of the meteorological data and other parameters（e.g. leaf area index（LAI）） of an oasis-desert transition zone in the middle stream of heihe river from 2005 to 2011, this paper calculated both reference（ET0） and actual evapotranspiration（ETc） using FAO56 Penman-Monteith and Penman-Monteith models, respectively. In combination with pan evaporation（Ep） measured by E601 pan evaporator, four aspects were analyzed：（1） ET0 was firstly verified by Ep;（2） Characteristics of ET0 and ETc were compared, while the influencing factors were also analyzed;（3） Since meteorological data are often unavailable for estimating ET0 through FAO56 Penman-Monteith model in this region, pan evaporation coefficient（Kp） is very important when using observed Ep to predict ET0. Under this circumstance, an empirical formula of Kp was put forward for this region;（4） Crop coefficient（Kc）, an important index to reflect evapotranspiration, was also analyzed. Results show that mean annual values of ET0 and ETc were 840 and 221 mm, respectively. On the daily bases, ET0 and ETc were 2.3 and 0.6 mm/d, respectively. The annual tendency of ET0 and ETc was very similar, but their amplitude was obviously different. The differences among ET0 and ETc were mainly attributed to the different meteorological variables and leaf area index. The calculated Kc was about 0.25 and showed little variation during the growing season, indicating that available water（e.g. precipitation and irrigation） of about 221 mm/a was required to keep the water balance in this region. The results provide an comprehensive analysis of evapotranspiration for an oasis-desert transition zone in the middle stream of heihe

关键词： evapotranspiration pan evaporation water requirement arid region oasis-desert transition zone

The effect of hydrologic process changes on NDVI in the desert-oasis ecotone of the Hexi Corridor

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science china Earth sciences 2014年第12期57卷 3107-3117页

作者： zhao wenzhi CHANG XueLi linze inland river basin research station Key Laboratory of Ecohydrology of Inland River Basin Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences School of Geography and Planning Ludong University

In the arid inland river basins of northwestern china,human activities control almost all the surface hydrologic *** potential effects of these altered hydrologic processes are gradually becoming clear,especially since the 2000 implementation of the integrated water resources management projects in the Shiyang river,the heihe river,the Tarim river,and the Shuler *** the appearance of these eco-hydrology changes and consequent environmental effects in the oasis has attracted broad attention,related research is still ***-hydrological process changes in the desert-oasis ecotone were investigated in the Pingchuan irrigation district in the middle reaches of the heihe *** results showed that the annual average amount of surface water irrigation during the past 20 years has decreased by 1.498×107 m3,while the annual average amount of well irrigation has increased by 1.457×107 m3,since 2000,when the State Council of china approved the water diversion scheme for the heihe river *** groundwater depth before the water diversion scheme generally varied between2.44–3.19 m(average 2.73±0.24 m),while that after the water diversion scheme has varied between 3.08–4.01 m(average3.79±0.62 m).The distribution area of3 m groundwater depth increased from 853 to 3843 ***,although the hydrologic processes changed dramatically,no significant effects on vegetation productivity in the desert-oasis ecotone were detected during the study period.

关键词： Hexi Corridor desert-oasis ecotone Pingchuan irrigation district hydrologic processes groundwater depth NDVI

The effects of the identity of shrub species on the distribution and diversity of ground arthropods in a sandy desert ecosystem of northwestern china

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research in cold and arid regions 2014年第6期6卷 587-596页

作者： JiLiang liu wenzhi zhao FengRui Li linze inland river basin research station Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of Sciences

Shrub is an important factor on structuring ground arthropod communities in desert ecosystems. In this study, in order to determine how shrubs and their species influence ground arthropod distribution patterns in a sandy desert scrubland dominated by two different shrub species, Calligonum mongolicum and Nitraria sphaerocarpa, the ground arthropods were sampled with pitfall traps during spring, summer and autumn. At the community level, total arthropod abundance was shown to be significantly higher under shrubs than in intershrub bare areas in spring; similar patterns occurred in terms of the richness of arthropod groups in the spring and over three seasons, suggesting season-specific shrub presence effects on arthropod activity. In addition, more arthropods were found under N. sphaerocarpa shrubs than under C. rnongolicum shrubs in autumn, suggesting season-specific effects of shrub species of arthropod activity, whereas more arthropods taxa were captured under C. mongoIicum than N. sphaerocarpa. At the trophic group level, the abundances of predator and herbivore arthropods were significantly greater under shrubs than in intershrub bare habitats, whereas herbivore arthropods were more abundant under N. sphaerocarpa than C. rnongolicum, and an opposite rule was detected for predator arthropods At the family level, the mean abundances of Carabidae, Curculionidae, Gnaphosidae and Lycosidae were significantly higher in the shrub microhabitats than in the intershrub bare habitat, there was no significant difference between habitats on the mean abundances of Formicidae and Tenebrionidae. The study results suggested that shrub presence and shrub species variation are important determinants of ground arthropod assemblages in this desert ecosystem, but the responses of ar- thropods differed among trophic and taxonomic groups.

关键词： heihe river basin sandy desert ecosystem ground arthropods shrub shrub species

Water consumption in artificial desert oasis based on net primary productivity

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science china Earth sciences 2010年第9期53卷 1358-1364页

作者： zhao wenzhi NIU ZuiRong CHANG XueLi LI ShouBo laboratory of ecohydrology and Integrated river basin science Cold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China linze inland river basin research station Chinese Ecosystem Research NetworkLanzhou 730000China Geography and Resource Management College Ludong UniversityYantai 264025China

Analysis of the water consumption is the basis for water allocation in oasis. However, the method of estimating oasis water consumption remains a great challenge. Based on net primary productivity (NPP) and the transpiration coefficient, a vegetation water consumption model was developed to estimate the water consumption in desert oasis in ERDAS environment. Our results demonstrated that the ecosystem in the middle reaches of the heihe oasis consumed water of 18.41×108-21.9×108 m3 for irrigation. Without taking precipitation into account, the water consumption in farmland accounted for 77.1%-77.8% (or about 13.97×108-16.84×108 m3) of the oasis vegetation water consumption and in the farmland protection system accounting for 22%. The growing period precipitation in desert environments is about 7.02×108 m3, and the total annual precipitation is about 8.29×108 m3. The modeled water consumption of desert vegetation, however, is about 4.57×108 m3, equivalent to only 65% of the growing period precipitation or 55% of the total annual precipitation. The modeled value equals to the cumulative precipitation of greater than 5 mm, which is defined as the effective precipitation in arid desert.

关键词： net primary productivity (NPP) transpiration coefficient water consumption oasis

Impact of soil conditions on the physiological characteristics of maize plants in an arid region, Northwest china

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research in cold and arid regions 2016年第4期8卷 334-342页

作者： LiWen zhao ZhiBin He wenzhi zhao linze inland river basin research station Chinese Ecosystem Network Research Key laboratory of ecohydrology of inland river basin Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences

Overuse of irrigation water to ensure the crop yield of maize plants has caused serious water shortage problems in the middle reach of heihe river, china. Thus, further research on the physiological characteristics, i.e., photosynthetic rate and leaf transpiration rate, are urgently needed to develop an efficient irrigation management system. In this paper, we selected two common soil textures （sandy loam, sand） and three one-time irrigation volumes （60 mm, 20 mm, 0 mm） in order to analyze the impact of soil conditions on the physiological characteristics of maize plants. Physiological and meteorological factors, soil water content and plant growing parameters were synchronously monitored on Jun. 30, Jul. 25 and Aug. 27 of 2012. The results indicate that sandy loam is better than sand for the growth of maize plants and single irrigation may provide limited influence on the physiological characteristics. Thus, increasing irrigation times and decreasing one-time volume is suggested for an efficient irrigation system.

关键词： photosynthesis leaf transpiration water use efficiency maize plant soil water content