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  • 宁夏河东沙地不同坡度柠条绵鸡儿(Caragana korshinskii)水分利用策略差异

    分类: 生物学 >> 生态学 提交时间: 2022-08-09 合作期刊: 《干旱区地理》

    摘要:为探讨全球气候变化背景下多元线性混合模型(IsoSource)和贝叶斯混合模型(MixSIAR)解析宁夏河东沙地柠条绵鸡儿(Caragana korshinskii)水分利用策略差异及适用性,利用氢氧稳定同位素技术,结合直接对比法、IsoSource模型和MixSIAR模型对比分析不同坡度(6°、10°、16°和24°)样地柠条绵鸡儿在生长季不同时期对各潜在水源的利用率,并评估两种模型的植物水分溯源效果。结果表明:柠条绵鸡儿对不同土层深度土壤水的利用存在明显的季节性差异,生长季初期,随着坡度的增大,柠条绵鸡儿对中层土壤水的利用率呈现出先增大后减小的趋势;生长季中期,随坡度增大,柠条绵鸡儿主要水分来源由深层土壤转移至浅层土壤;生长季后期,柠条绵鸡儿主要水分来源随着坡度的增大由浅层土壤转移至深层土壤。基于直接对比法的定性判断结果,IsoSource模型和MixSIAR模型计算坡度6°、10°和16°样地柠条锦鸡儿主要水分来源利用率的适用性均较高;而Mix⁃SIAR模型计算坡度24°样地柠条绵鸡儿主要的水分来源以及其贡献率具有更高的可靠性。Iso⁃Source模型更适合解析较小坡度(6°和16°)样地柠条绵鸡儿的水分利用策略;而MixSIAR模型解析较大坡度(10°和24°)样地柠条绵鸡儿水分利用策略的适用性更好。研究结果可为我国干旱区植物水分来源鉴别方法的选择提供科学参考。

  • 基于Cubist 模型的天山北坡草地鼠群密度时空分布特征

    分类: 生物学 >> 生态学 提交时间: 2022-08-09 合作期刊: 《干旱区地理》

    摘要:鼠害是影响草原生态健康的重要因素,了解小型啮齿动物种群密度时空分布特征,对精准的鼠害综合防治具有重要意义。以往对小型啮齿动物时空分布的研究多局限于静态的站点分布或小范围的种群密度时间变化分析,缺乏对较大时空尺度小型啮齿动物种群密度变化的分析。从已发表的文献中收集了天山北坡草地1982—2015年小尺度的有效洞口密度实地调查信息,同时结合环境因子数据,再根据海拔将研究区划分为≤900 m和>900 m 2类,运用Cubist模型和随机森林模型,分析有效洞口密度时空分布。结果表明:(1)1982—2015年天山北坡海拔≤900 m地区的有效洞口密度总体呈增加趋势,而海拔>900 m的地区总体呈减少趋势。基于Cubist模型构建有效洞口密度与环境因子的模型拟合精度明显优于随机森林模型。(2)植被状况、气象因子和放牧强度是天山北坡有效洞口密度时空分布主要的环境驱动因素。在天山北坡内海拔≤900 m和>900 m的地区中,有效洞口密度的驱动机制存在着显著差异。(3)在海拔≤900 m地区,影响有效洞口密度时空分布主要是叶面积指数,而对于海拔>900 m地区为归一化植被指数。这可能是受到大沙鼠(Rhom⁃bomys opimus)和黄兔尾鼠(Eolagurus luteus)消耗不同类型植被的影响。

  • Tree-ring δ15N of Qinghai spruce in the central Qilian Mountains of China: Is pre-treatment of wood samples necessary?

    分类: 生物学 >> 生态学 提交时间: 2022-06-20 合作期刊: 《干旱区科学》

    摘要:Abstract: A knowledge of the tree-ring stable nitrogen isotope ratio (δ15N) can deepen our understanding of forest ecosystem dynamics by indicating the long-term availability, cycling and sources of nitrogen (N). However, the radial mobility of N blurs the interannual variations in the long-term N records. Previous studies of the chemical extraction of tree rings before analysis had produced inconsistent results and it is still unclear whether it is necessary to pre-treat wood samples from specific tree species to remove soluble N compounds before determining the δ15N values. We compared the effects of pre-treatment with organic solvents and hot ultrapure water on the N concentration and δ15N of tree rings from endemic Qinghai spruce (Picea crassifolia) growing in the interior of the central Qilian Mountains, China, during the last 60 a. We assessed the effects of different preparation protocols on the removal of the labile N compounds and investigated the need to pre-treat wood samples before determining the δ15N values of tree rings. Increasing trends of the tree-ring N concentration were consistently observed in both the extracted and unextracted wood samples. The total N removed by extraction with organic solvents was about 17.60%, with a significantly higher amount in the sapwood section (P<0.01). The δ15N values of tree rings decreased consistently from 1960 to 2019 in both the extracted and unextracted wood samples. Extraction with organic solvents increased the δ15N values markedly by about 5.2‰ and reduced the variations in the δ15N series. However, extraction with hot ultrapure water had little effect, with only a slight decrease in the δ15N values of about 0.5‰. Our results showed that the radial pattern in the inter-ring movement of N in Qinghai spruce was not minimized by extraction with either organic solvents or hot ultrapure water. It is unnecessary to conduct hot ultrapure water extraction for the wood samples from Qinghai spruce because of its negligible effect on the removal of the labile N. The δ15N variation trend of tree rings in the unextracted wood samples was not influenced by the heartwood–sapwood transition zone. We suggest that the δ15N values of the unextracted wood samples of the climate-sensitive Qinghai spruce could be used to explore the ecophysiological dynamics while focusing on the long-term variations.

  • Dependency of litter decomposition on litter quality, climate change, and grassland type in the alpine grassland of Tianshan Mountains, Northwest China

    分类: 生物学 >> 生态学 提交时间: 2022-06-17 合作期刊: 《干旱区科学》

    摘要:

    Abstract: Litter decomposition is an important component of the nutrient recycling process and is highly sensitive to climate change. However, the impacts of warming and increased precipitation on litter decomposition have not been well studied, especially in the alpine grassland of Tianshan Mountains. We conducted a manipulative warming and increased precipitation experiment combined with different grassland types to examine the impact of litter quality and climate change on the litter decomposition rate based on three dominant species (Astragalus mongholicus, Potentilla anserina, and Festuca ovina) in Tianshan Mountains from 2019 to 2021. The results of this study indicated there were significant differences in litter quality, specific leaf area, and leaf dry matter content. In addition, litter quality exerted significant effects on litter decomposition, and the litter decomposition rate varied in different grassland types. Increased precipitation significantly accelerated the litter decomposition of P. anserina; however, it had no significant effect on the litter decomposition of A. mongholicus and F. ovina. However, warming consistently decreased the litter decomposition rate, with the strongest impact on the litter decomposition of F. ovina. There was a significant interaction between increased precipitation and litter type, but there was no significant interaction between warming and litter type. These results indicated that warming and increased precipitation significantly influenced litter decomposition; however, the strength was dependent on litter quality. In addition, soil water content played a crucial role in regulating litter decomposition in different grassland types. Moreover, we found that the litter decomposition rate exhibited a hump-shaped or linear response to the increase of soil water content. Our study emphasizes that ongoing climate change significantly altered litter decomposition in the alpine grassland, which is of great significance for understanding the nutrient supply and turnover of litter.

  • Water use characteristics of different pioneer shrubs at different ages in western Chinese Loess Plateau: Evidence from δ2H offset correction

    分类: 生物学 >> 生态学 提交时间: 2022-06-17 合作期刊: 《干旱区科学》

    摘要:

    Abstract: Caragana korshinskii Kom. and Tamarix ramosissima Ledeb. are pioneer shrubs for water and soil conservation, and for windbreak and sand fixation in arid and semi-arid areas. Understanding the water use characteristics of different pioneer shrubs at different ages is of great importance for their survival when extreme rainfall occurs. In recent years, the stable isotope tracing technique has been used in exploring the water use strategies of plants. However, the widespread δ2H offsets of stem water from its potential sources result in conflicting interpretations of water utilization of plants in arid and semi-arid areas. In this study, we used three sets of hydrogen and oxygen stable isotope data (δ2H and δ18O, corrected δ2H_c1 based on SW-excess and δ18O, and corrected δ2H_c2 based on −8.1‰ and δ18O) as inputs for the MixSIAR model to explore the water use characteristics of C. korshinskii and T. ramosissima at different ages and in response to rainfall. The results showed that δ2H_c1 and δ18O have the best performance, and the contribution rate of deep soil water was underestimated because of δ2H offset. During the dry periods, C. korshinskii and T. ramosissima at different ages both obtained mostly water from deeper soil layers. After rainfall, the proportions of surface (0–10 cm) and shallow (10–40 cm) soil water for C. korshinskii and T. ramosissima at different ages both increased. Nevertheless, there were different response mechanisms of these two plants for rainfall. In addition, C. korshinskii absorbed various potential water sources, while T. ramosissima only used deep water. These flexible water use characteristics of C. korshinskii and T. ramosissima might facilitate the coexistence of plants once extreme rainfall occurs. Thus, reasonable allocation of different plants may be a good vegetation restoration program in western Chinese Loess Plateau.

  • Spatiotemporal variations and driving factors of habitat quality in the loess hilly area of the Yellow River Basin: A case study of Lanzhou City, China

    分类: 生物学 >> 生态学 提交时间: 2022-06-17 合作期刊: 《干旱区科学》

    摘要:

    Abstract: Rapid industrialization and urbanization have led to the most serious habitat degradation in China, especially in the loess hilly area of the Yellow River Basin, where the ecological environment is relatively fragile. The contradiction between economic development and ecological environment protection has aroused widespread concern. In this study, we used the habitat quality of Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST-HQ) model at different scales to evaluate the dynamic evolution characteristics of habitat quality in Lanzhou City, Gansu Province of China. The spatiotemporal variations of habitat quality were analyzed by spatial autocorrelation. A Geographical Detector (Geodetector) model was used to explore the driving factors that influencing the spatial differentiation of habitat quality, including natural factors, socio-economic factors, and ecological protection factors. The results showed that the habitat quality index of Lanzhou City decreased from 0.4638 to 0.4548 during 2000–2018. The areas with reduced the habitat quality index were mainly located in the Yellow River Basin and Qinwangchuan Basin, where are the main urban areas and the new economic development areas, respectively. The spatial distribution of habitat quality presented a trend of high in the surrounding areas and low in the middle, and showed a significant positive spatial autocorrelation. With the increase of study scale, the spatial distribution of habitat quality changed from concentrated to dispersed. The spatial differentiation of habitat quality in the study area was the result of multiple factors. Among them, topographic relief and slope were the key factors. The synergistic enhancement among these driving factors intensified the spatial differentiation of habitat quality. The findings of this study can provide a scientific basis for land resources utilization and ecosystem restoration in the arid and semi-arid land.

  • Changes in diversity, composition and assembly processes of soil microbial communities during Robinia pseudoacacia L. restoration on the Loess Plateau, China

    分类: 生物学 >> 生态学 提交时间: 2022-06-13 合作期刊: 《干旱区科学》

    摘要:

    Abstract: Robinia pseudoacacia L. (RP) restoration has increased vegetation cover in semi-arid regions on the Loess Plateau of China, but ecological problems have also occurred due to RP restoration, such as reduced soil moisture. Further, it is still uncertain how microbial diversity, composition and assembly processes change with RP restoration in semi-arid regions. Therefore, amplicon sequencing of small subunit ribosomal ribonucleic acid (16S rRNA) and internal transcribed spacer (ITS) genes was performed to study soil bacterial and fungal diversity, composition and assembly processes at four study sites with different stand ages of RP plantations (Y10, RP plantation with stand ages less than 10 a; Y15, RP plantation with stand ages approximately 15 a; Y25, RP plantation with stand ages approximately 25 a; and Y40, RP plantation with stand ages approximately 40 a) along a 40-a chronosequence on the Loess Plateau. The diversity of soil bacteria and fungi increased significantly during the restoration period from 10 to 15 a (P<0.05). However, compared with Y15, bacterial diversity was lower at Y25 and Y40, and fungal diversity remained stable during the restoration period between 25 and 40 a. The relative abundances of Proteobacteria and Ascomycota increased during the restoration period from 10 to 15 a. Conversely, after 15 a of restoration, they both decreased, whereas the relative abundances of Actinomycetes, Acidobacteria and Basidiomycota gradually increased. The variations in soil bacterial communities were mainly related to changes in soil total nitrogen, nitrate nitrogen and moisture contents, while soil fungal communities were mainly shaped by soil organic carbon and nitrate nitrogen contents. Bacterial communities were structured by the heterogeneous selection and stochastic process, while fungal communities were structured primarily by the stochastic process. The RP restoration induced an increase in the relative importance of heterogeneous selection on bacterial communities. Overall, this study reveals the changes in microbial diversity, community composition and assembly processes with RP restoration on the Loess Plateau and provides a new perspective on the effects of vegetation restoration on soil microbial communities in semi-arid regions.

  • 干旱区梨园不同覆盖条件下土壤环境因子综合性评价研究

    分类: 生物学 >> 生态学 提交时间: 2022-06-09 合作期刊: 《干旱区地理》

    摘要:

    在干旱沿黄灌区开展不同覆盖材料配合滴灌的灌溉保墒方式下,进一步研究了不同覆盖方
    式对梨园全生育期的土壤理化性状和养分含量变化影响,分析了土壤温度、水分、pH等和矿质营养
    元素间的相互关系,对覆盖后的土壤质量进行了综合性评价。试验处理分为无覆盖对照(T1)、园
    艺地布覆盖(T2)、玉米秸秆覆盖(T3)和黑地膜覆盖(T4)4个处理;试验设计为随机区组设计,每个
    处理小区均为167株梨树(约占地667 m2),重复3次;各小区土样分0~20 cm、20~40 cm、40~60 cm
    土层取样。结果表明:(1)园艺地布和黑地膜覆盖处理有一定的增温效应,而玉米秸秆覆盖有较好
    的降温和稳温效应,且增墒效应明显,土壤含水率比其他3种处理显著提高了1.0%~2.7%。(2)相较
    无覆盖处理,黑地膜覆盖可提升表层土壤pH,并加速表层土壤有机质的分解,有机质含量较无覆盖
    处理下降33.1%;玉米秸秆覆盖可显著降低各土层的土壤pH,降低范围为1.8%~4.6%,并促进0~20
    cm土层有机质的提升,土壤有机质含量增加12.2%;园艺地布覆盖下0~40 cm土层内土壤有机质含量
    和全盐量均有降低。(3)黑地膜覆盖下0~20 cm和20~40 cm土层的碱解氮含量分别为73.00 mg·g-1和
    64.53 mg·g-1,均显著地高于无覆盖处理,无覆盖条件下土壤碱解氮在深层(40~60 cm土层)积累较
    多,显著地高于玉米秸秆和黑地膜覆盖;各处理0~20 cm和20~40 cm土层速效磷含量差异显著,大
    小顺序均为T4>T3>T2>T1,玉米秸秆覆盖可提升土壤速效钾和速效铁的含量。(4)进行主成分分析
    表明不同覆盖方式对梨园浅层土壤环境因子的影响要明显大于深层土壤,在0~40 cm土层内各覆
    盖处理效果均好于无覆盖处理,其中玉米秸秆覆盖在0~20 cm和20~40 cm土层综合得分分别为
    1.189和0.326,覆盖效果最佳。

  • 胡麻生理生化代谢指标对干旱胁迫的 响应及其模拟模型的研究

    分类: 生物学 >> 生态学 提交时间: 2022-06-08 合作期刊: 《干旱区地理》

    摘要:

    为进一步研究胡麻生理生化代谢指标响应干旱胁迫时对胡麻产量的影响,采用盆栽控水法模拟胡麻干旱胁迫,依据2013—2014年甘肃省定西市西巩驿镇胡麻试验数据,建立并检验胡麻干旱胁迫模型,模拟干旱胁迫时对胡麻生理生化指标及产量影响,利用均方根误差(RMSE)和决定系数(R2)描述模型拟合度。结果表明:(1)模型产量模拟值的RMSE为41.3159~155.6685 kg·hm-2,平均值为80.1837 kg·hm-2;R2为0.8929~0.9894,平均值为0.9387,该模型具有较好的拟合度、可行性也较强。(2)在重度干旱胁迫下,抗氧化代谢指标——超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)中,CAT活性表现趋势为下降,终花期POD活性增幅(26.09%~28.00%)最大;渗透调节的3种物质含量均显著上升,其中脯氨酸增幅最大,达236.22%。(3)呈现出极显著相关性的各指标有3组,分别是脯氨酸与叶绿素、丙二醛和CAT活性;可溶性蛋白与丙二醛和CAT活性;POD活性与SOD活性。胡麻生理生化指标响应不同程度干旱胁迫与胡麻的产量有极强的关联,此模型的建立是对胡麻生理生化指标响应干旱胁迫的科学补充,进一步为胡麻的高效生产管理及农业生产系统提供理论依据和支持。

  • 华北一作区马铃薯生长发育及产量对干旱胁迫响应的模拟研究 ——以武川县为例

    分类: 生物学 >> 生态学 提交时间: 2022-06-08 合作期刊: 《干旱区地理》

    摘要:

    为探究不同程度干旱胁迫对华北一作区马铃薯生长发育及产量的影响,以内蒙古呼和浩特市武川县为例,基于多年马铃薯生长发育资料和气象资料,对APSIM-Potato模型进行调参与验证,评价模型在武川地区的适用性。利用验证后的模型模拟马铃薯叶面积指数(LAI)、地上部生物量和产量对不同发育阶段干旱胁迫的响应。结果表明:(1)各发育阶段天数的模拟值与实测值的均方根误差(RMSE)均在3 d内;LAI、地上部生物量和产量的模拟值与实测值的归一化均方根误差(NRMSE)分别为12.82%、17.35%和14.48%,均低于20%,表明APSIM-Potato模型在武川地区具有较好的适用性。(2)随着干旱胁迫时间和强度的增加,马铃薯LAI、地上部生物量和产量随之减小。模拟单一发育阶段干旱胁迫时,马铃薯LAI、地上部生物量和产量对分枝-开花期水分胁迫的响应最大;模拟连续发育阶段干旱胁迫时,LAI、地上部生物量和产量对全生育期水分胁迫的响应最大。

  • 根系水分胁迫响应函数对土壤水及作物生长动态和产量模拟影响的研究

    分类: 生物学 >> 生态学 提交时间: 2022-04-16 合作期刊: 《干旱区地理》

    摘要:

    为探究根系水分胁迫响应函数对农田水分动态及产量模拟的影响,基于Richards方程和 PS123作物生长模型分别进行了土壤水分动态和小麦产量的模拟,对比分析了VGS型曲线)、MP (凹凸型曲线)及LSS型曲线)3种水分胁迫响应函数。采用山西省霍泉站(3 a)及潇河站(
    2 a)的试验资料对模型中的土壤水力特征参数、水分胁迫响应函数参数进行反演,确定最优的参数值,得到了土壤含水率、蒸散量及籽粒产量的模拟结果。结果表明:(1VGMPLS函数条件下的土壤水 R 分及产量模拟结果均较好,回归估计标准误差(RMSE)值在0.021~0.036之间,模拟值与实测值间的检验达到了极显著水平;对于霍泉站,VGMPLS函数条件下,土壤含水率模拟值与实测值的平均相对误差分别为6.37%8.26%7.18%,相关性系数值最小为0.7814,模拟产量的平均相对误差值分别为8.73%8.40%8.42%;对于潇河站,土壤含水率模拟值与实测值的平均相对误差结果普遍大于霍泉站,最大为12.47%。(2)土壤水分动态模拟,S型曲线的水分胁迫响应函数较凹凸型曲
    线的水分胁迫响应函数表现出了更好的效果,其中使用VG函数模拟的平均相对误差较小,模拟的蒸散量更接近于实测值。(3)产量模拟,
    3种水分胁迫响应函数差异不明显。综上,VG函数是一种精度较高的根系水分胁迫响应函数,且模型简洁、方便;改进的LS函数能够提高模拟精度,但模型的稳定性有待近一步研究。

  • 油莎豆(Cyperus esculentus)耕作区作物残茬对农田风蚀的影响

    分类: 生物学 >> 生态学 提交时间: 2022-04-16 合作期刊: 《干旱区地理》

    摘要:

    油莎豆(Cyperus esculentus)是一种油料作物,其对土壤养分要求低,因此适合在我国北方风沙区推广种植,以调整农业种植结构。然而在采收过程中对土地的扰动,会潜在增加农田风蚀的风险,因此需要对油莎豆残茬的生态效益进行探究与评估。基于野外集沙实验和风速廓线测定实验,对油莎豆与梭梭间作未采收、油莎豆纯作留4垄采6垄和油莎豆纯作留6垄采63种残茬类型的防风固沙能力进行了系统研究。结果表明:油莎豆与梭梭间作残茬类型中的输沙通量最低,总输沙通量显著小于其他2种模式(P<0.05),并且空气动力学粗糙度(0.553 cm1.156 cm)和摩阻速度(0.3040.332)也最高。留4垄采6垄模式输沙通量随时间增加,甚至超过全采收模式,空气动力学粗糙度接近于0,且摩阻速度最低。留6垄采6垄模式输沙通量则介于前两者之间,空气动力学粗糙度为0.100 cm0.137 cm,摩阻速度为0.2400.272。总体而言,单一的宽条带式油莎豆残茬削减风速的作用不如高低穿插搭配的作物残茬。油莎豆种植可以考虑选择合适的采收间距及搭配合适的直立植物进行间作,以在油莎豆采收后漫长的休耕期进行留茬以减轻风蚀保护农田。休耕期合理的作物留茬是减轻土壤风蚀的关键措施之一,这对于干旱区农田的可持续发展具有重要的生态价值。

  • 伊犁河上游河谷水库浮游动物分布及水环境特征 ——以恰甫其海为例

    分类: 生物学 >> 生态学 提交时间: 2022-04-14 合作期刊: 《干旱区地理》

    摘要:

    为研究新疆伊犁河谷上游水库水环境质量状况,基于生物多样性指数、综合营养状态指数、 冗余分析(RDA)等方法,于20196月(丰水期)、9月(平水期)和12月(枯水期)对恰甫其海水库浮游动物及水环境理化指标进行了调查分析。结果表明:(1)恰甫其海共检出浮游动物37,其中原生动物17种,轮虫10,枝角类4种,桡足类6种;优势种主要包括侠盗虫属Strobilidium sp.)、匣壳 虫属(Centropyxis sp.)、王氏似铃壳虫Tintinnopsis wangi)、疣毛轮属(Synchaeta sp.)、广布多肢轮虫 Polyarthra vulgaris),共5种;浮游动物丰水期、平水期和枯水期丰度分别为580.40 ind·L-1152.68 ind·L-1137.01 ind·L-1,生物量分别为0.550 mg·L-10.018 mg·L-10.007 mg·L-1,丰度和生物量最大值 均出现在丰水期。(2)浮游动物多样性指数存在典型的时空分布特征,Shannon-Wiener指数(H)和 Margalef指数(D)在丰水期呈现由库尾向坝前增高的趋势,在平水期和枯水期以库中最高,HD值分别为 1.19 0.82。(3RDA 结果表明,水温(
    WT)、化学需氧量CODMn)和营养盐浓度如总氮 TN)、总磷(TP)、硝酸盐氮(NO-3 -N)、亚硝酸盐氮NO-2 -N)、氨态氮(NH+4 -N)、正磷酸盐(PO34- -P等是影响浮游动物群落结构变化的主要环境因子。综合生物多样性指数和综合营养状态指数结果表
    明,恰甫其海水质处于贫-中营养状态,水环境质量状况良好,可以作为鱼类越冬场、产卵场和索饵场。

  • 3 种滨河植物单根抗拉特性与其微观结构关系

    分类: 生物学 >> 生态学 提交时间: 2022-03-28 合作期刊: 《干旱区研究》

    摘要:

    为分析黄河源区高寒草甸植物单根的抗拉力学性质及其护岸的微观力学机理,以华扁穗草、线叶嵩草和金露梅3种优势滨河植物为研究对象,通过开展单根拉伸试验和石蜡切片试验,定量分析3种植物单根力学特性及其与微观结构的关系。结果表明,当根径在<0.5 mm0.5~1.0 mm>1.0 mm 3个根径级别时,3种植物单根抗拉力和延伸率均随根径增大而增大;单根抗拉强度和杨氏模量均随根径增大而减小;根系应力-应变曲线表现为单峰曲线。灌木金露梅单根平均抗拉强度是草本植物华扁穗草和线叶嵩草的1.56倍和1.25倍,华扁穗草单根平均延伸率是线叶嵩草和金露梅的1.06倍和1.36倍。草本植物单根抗拉强度主要与其维管柱面积占比有关;而灌木金露梅单根抗拉强度主要与其周皮和次生木质部面积占比有关。综合来看,华扁穗草和线叶嵩草根系抵抗变形的能力较强,主要发挥加筋和减缓河岸变形、破坏的作用;而金露梅刚度强、抗拉强度较大,主要发挥固土护岸的作用。研究结果可为筛选黄河源区优势护岸植物提供科学依据。

  • 黄河源区不同退化程度高寒草地理化性质及复合体抗剪强度研究

    分类: 生物学 >> 生态学 提交时间: 2022-03-28 合作期刊: 《干旱区研究》

    摘要:

    为研究黄河源区高寒草地退化对土体理化性质及根-土复合体抗剪强度影响,本研究以位于黄河源区青海河南县地区高寒草地为研究对象,通过开展不同退化程度草地野外取样及室内试验,获得土体密度、含水率、颗粒级配、土壤营养元素和植物根-土复合体抗剪强度指标及变化特征。结果表明:(1)在相同退化程度和取样深度下,南旗村试验区土体平均密度为启龙牧场的1.02~1.29倍,土体含水率表现出随着草地退化程度加剧而降低;2个试验区土壤有机质、全氮、全磷等随着草地退化程度加剧而降低。(2)区内根-土复合体抗剪强度随草地退化程度加剧而降低,启龙牧场与南旗村试验区其上层(0~10 cm)、下层(10~20 cm)降低幅度分别为72.05%48.77%77.26%81.37%;进一步研究表明,根-土复合体所含根系数量和根系干重表现出随着草地退化程度加剧呈逐渐降低,启龙牧场与南旗村试验区其上层和下层的根-土复合体所含根系数量降低幅度分别为79.28%75.93%92.48%39.59%。(3)根据WWM模型和Pearson相关性分析结果可知,根系数量和营养元素含量减少对根-土复合体抗剪强度具有显著降低作用。本研究结果对于黄河源区高寒草地合理防治草地退化,以及水土流失、浅层滑坡等灾害具有实际指导意义。

  • 黄土沟壑区黑麦草植被冠层与根系坡面水沙效益及水力特性

    分类: 生物学 >> 生态学 提交时间: 2022-02-11 合作期刊: 《干旱区地理》

    摘要:

    基于野外人工模拟降雨试验和黑麦草全植被结构、根系结构及裸坡结构,通过设置不同雨 强(30 mm·h-160 mm·h-190 mm·h-1)和不同下垫面坡度(),对坡面产流产沙特征、水力参数分布变化及坡面侵蚀特征和水力特征关系进行了分析,揭示了不同草被结构类型下坡面产流产沙特征与水力特性。结果表明:随着雨强和坡度的变化,全植被坡面具有最小的产流产沙率,根系坡面次之,产流产沙率最大的则是裸坡坡面。黑麦草冠层的减流贡献率优于根系,冠层与根系的平均减流贡献率分别可达到62%38%,减沙贡献率则是根系优于冠层,冠层与根系的平均减沙贡献率分别可达到37%65%,以上产流产沙特征均揭示了草本植被冠层和根系在抑制侵蚀当中的有效性。水力参数中,雷诺数和水流功率是适用的2个水力指标,与产流产沙速率显著相关 P<0.01)。本次研究可为不同草被结构下的水土保持效益提升以及水力特性的分析提供理论依据和试验参考。

  • 祁连山东段山地典型灌丛枯落物及土壤水源涵养功能研究

    分类: 生物学 >> 生态学 提交时间: 2022-02-11 合作期刊: 《干旱区地理》

    摘要:

    为探讨高寒地区灌丛枯落物层及土壤层的水源涵养功能,以祁连山东段6种典型灌丛的枯 落物和土壤为研究对象,采用野外调查与室内浸泡相结合的方法,对枯落物及土壤水文特征进行了研究。结果表明:(16种灌丛枯落物的蓄积量范围为0.23~3.61 t·hm-2,大小排序为山生柳>硬叶>绣线菊>金露梅>头花杜鹃>千里香杜鹃。(2)枯落物最大持水量范围为0.57~10.59 t·hm-2,山生柳最大,千里香杜鹃最小;最大持水率变化范围为 147.30%~293.28%山生柳最大绣线菊最小36种灌丛枯落物的持水量Y)与浸泡时间t符合对数函数关系Y=klnt+bR2>0.967;吸水速率 V)与浸泡时间t)符合幂函数关系V=KtnR2>0.823。(4)最大拦蓄量和有效拦蓄量均为山生柳>叶柳>金露梅>绣线菊>千里香杜鹃>头花杜鹃。(56种灌丛土壤容重范围为0.69~0.95 g·cm-3,山生柳最大,千里香杜鹃最小;土壤总孔隙度范围为60.94%~68.75%,千里香杜鹃最大,绣线菊最小;土壤最大持水量范围为609.44~687.46 t·hm-2,千里香杜鹃最大,绣线菊最小。(6)根据坐标综合评定法分析得出,山生柳灌丛的水源涵养功能最优。

  • 新疆准噶尔盆地未开垦盐碱土盐分与盐生植被多样性分析

    分类: 生物学 >> 生态学 提交时间: 2022-02-11 合作期刊: 《干旱区地理》

    摘要:

    以新疆准噶尔盆地未开垦盐碱土为研究对象,测量土壤含盐量、pH、电导率、八大离子等指标,采用多元统计、主成分分析法(PCA)对采样区盐碱土分布特征与盐生植被多样性进行研究。结果表明:(1)研究区以硫酸盐-氯化物盐土、硫酸盐盐土为主。中、重度硫酸盐-氯化物盐土、硫酸盐盐土以链状或条带状集中分布在昌吉回族自治州、博尔塔拉蒙古自治州。阿勒泰地区的苏打盐土、苏打碱土呈点状分布。(2)昌吉回族自治州以真盐植被为优势种,如梭梭(Haloxylon ammodendron)和叉毛蓬(Petrosimonia sibirica);博尔塔拉蒙古自治州以泌盐植被为优势种,如琵琶柴(Reaumuria songarica)、骆驼刺(Alhagi sparsifolia)。(3)二次多项式较好地表达了土壤盐分与植被多样性关系,土壤含盐量在5~10 mg·g-1 之间时,Shannon-Wiener指数、Hurlbert指数、Pielou均匀度指数达到最大值;pH8.4~9.2范围内,盐生植被物种更为丰富,分布较均匀。(4)盐生植被优势种与土壤性状的PCA分析表明,土壤盐分是影响琵琶柴、梭梭、猪毛菜Salsola collina)、柽柳(Tamarix chinensis)分布的关键因子,而刺毛碱蓬Suaeda acuminata)、唐古特白刺Nitraria tangutorum)主要受土壤 pHCO23 - 的影响。本研究为未开垦土地资源的合理利用、生态修复提供理论依据。

  • 不同演替阶段白刺灌丛沙堆土壤因子与 叶功能性状关系研究

    分类: 生物学 >> 生态学 提交时间: 2022-02-11 合作期刊: 《干旱区地理》

    摘要:

    植物功能性状与环境之间的关系是功能性状研究的重点,环境因子驱使植物功能性状发生变化,进而推动群落发生演替。本研究以民勤不同演替阶段(发育阶段、稳定阶段、衰退阶段、严重衰退阶段)白刺(Nitraria tangutorum)灌丛沙堆为研究对象,分析不同演替阶段白刺叶功能性状差异及其与土壤因子的关系,旨在揭示白刺对干旱荒漠区土壤环境的适应策略。结果表明:(1)不同演替阶段白刺叶厚度、叶干物质含量、叶全磷含量差异显著(P<0.05),其他的叶功能性状差异不显 著(P>0.05)。白刺叶功能性状变异范围是 0.39%~11.99%,均表现为弱变异,其中比叶面积最大 11.99%),叶全碳含量最小(0.39%)。(2)白刺叶功能性状间存在一定的相关性;叶厚度、叶干物质含量、叶全氮含量可作为白刺叶功能性状变化的主要指标。(3)除pH外,白刺灌丛沙堆土壤因子随退化程度的增加表现为先增加后降低的趋势,最小值出现在发育阶段,最大值出现在衰退阶段。土壤速效磷含量与全氮含量是影响白刺叶功能性状变化的主要土壤因子。上述研究结果深化了对白刺灌丛沙堆演替的认识,为荒漠生态系统恢复与保护提供重要参考依据。

  • 地形因子对陕北黄土丘陵区防护林树种分布的影响

    分类: 生物学 >> 生态学 提交时间: 2021-12-14 合作期刊: 《干旱区地理》

    摘要: 为了解地形因子对树种分布变化的影响,更科学地进行防护林空间配置,本研究利用陕西 省延安市吴起县数字高程模型(DEM)数据以及两期树种分布数据,采用 Pearson 相关分析和随机森林模型,探讨陕西省延安市吴起县典型造林树种[刺槐(Robinia pseudoacacia)、山杏(Armeniaca si⁃birica)、油松(Pinus tabuliformis)和沙棘(Hippophae rhamnoides)]与地形因子(海拔、坡度、坡向、曲 率、地形起伏度和地形粗糙度)的关系。结果表明:(1)2007—2019 年刺槐、山杏和油松的分布呈增 加趋势,研究区内分别在 83.373%、73.271%和 72.415%的区域呈增加趋势;沙棘的分布呈减少趋 势,在 61.737%的区域衰退。(2)通过 Pearson 相关分析和随机森林重要性检验,海拔和坡向是影响 黄土高原地区典型造林树种分布的主要地形因子。(3)4 种主要造林乔灌木树种刺槐、山杏、油松和 沙棘适宜生长海拔范围分别为 1410.105~1510.215 m、1444.873~1553.210 m、1380.132~1451.762 m 和 1365.621~1562.348 m。(4)刺 槐 适 宜 生 长 坡 向 范 围 为 0~20.520° 、50.280° ~62.310° 、82.440° ~ 95.280°和 277.280°~360.000°;山杏适宜生长坡向范围为 0~81.270°和 265.310°~360.000°;油松适宜 生长坡向范围为 0~100.180°;沙棘适宜生长坡向范围为 0~74.540°和 280.820°~360.000°。