, 张家豪, 王聪聪清华大学 水利水电工程系, 水沙科学与水利水电工程国家重点实验室, 北京 100084
收稿日期：2022-11-08
基金项目：国家自然科学基金项目(U2243222, U2240207); 第2次青藏高原综合科学考察项目(2019QZKK0903)
作者简介：周雄冬(1991—), 男, 助理研究员
通讯作者：徐梦珍, 副教授, E-mail：mzxu@mail.tsinghua.edu.cn
摘要：侧向水文连通性改变了河流系统的水动力条件和营养状况, 进而对生物群落的多样性、结构和功能造成影响。对侧向水文连通性的研究多集中于平原河流, 侧向水文连通性对高原河流系统的生态影响尚待厘清。该文采用野外采样、现场测量和室内鉴定分析相结合的方法, 以大型无脊椎底栖动物为水生态指示生物, 以青藏高原东北部青海湖的支流泉吉河为研究区域, 分析了不同侧向水文连通条件下典型高原河流系统的环境条件差异和底栖动物群落差异。结果表明：侧向水文连通性与底栖动物群落的多样性、结构和功能特征均有较强关联; 泉吉河流域的底栖动物多样性对侧向水文连通性降低均呈“先降低后升高”的单谷式响应, 显著区别于平原河流的单峰式响应模式。高原河流“低代谢、寡营养”的本底条件造成底栖动物对扰动敏感, 底栖动物群落偏好的中度干扰条件由中等水文连通环境向低水文连通环境偏移, 是造成单谷响应模式的重要原因。
关键词：废弃河道群落生境物种多样性功能摄食类群功能习性类群青藏高原
Response of benthic macroinvertebrates in highland rivers to the lateral hydrological connectivity: Taking the Quanji River as an example
ZHOU Xiongdong, LIU Yibo, XU Mengzhen
, ZHANG Jiahao, WANG CongcongState Key Laboratory of Hydroscience and Engineering, Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China
Abstract: Objective Lateral hydrological connectivity alters the hydrodynamic and trophic conditions of a river system, which further affects the diversity, structure, and function of biotic assemblages. Previous studies focusing on lateral hydrological connectivity are mostly conducted on lowland river systems, whereas the ecological effects on highland rivers have yet to be explored. The objectives of this study are as follows: (1) to investigate the benthic macroinvertebrate assemblages in a typical highland river to facilitate the identification of different biotopes based on the macroinvertebrate traits; (2) to characterize biotopes according to the environmental conditions (especially in response to lateral hydrological connectivity), macroinvertebrate diversity, and morphological and functional structures; and (3) to analyze the pattern of how the benthic macroinvertebrate assemblages respond to variation in lateral hydrological connectivity. Methods We adopted a combined approach of field sampling, in situ measurement, and laboratory observation. Using benthic macroinvertebrate assemblages as indicators, we analyzed the ecological differences among biotopes with different lateral hydrological connectivities in the Quanji River, a typical highland river in northeastern Qinghai Lake, Qinghai Province, China. Ecological data were analyzed using the following methods: (1) ordination (canonical correspondence analysis, CCA) to analyze the general distribution patterns of macroinvertebrate taxa along critical environmental variable gradients; (2) hierarchical clustering and nonmetric multidimensional scaling (NMDS) based on the pairwise Bray-Curtis distance of macroinvertebrate assemblages to identify the representative biotopes; and (3) ANOVA and Kruskal-Wallis analysis to detect the significant differences in environmental variables and macroinvertebrate indices and to quantify how ecological characteristics respond to the variations in the lateral hydrological connectivity. Results Our results showed the following: (1) a total of 122 195 macroinvertebrate specimens were collected from the Quanji River, representing 33 families and 61 genera; (2) macroinvertebrate taxa exhibited different preferences to the environmental conditions and formed a featured distribution along the environmental gradients; (3) results of hierarchical clustering identified four types of biotopes (e.g., G1—G4) for the Quanji River based on the macroinvertebrate dissimilarity as measured by the Bray-Curtis distance, and samples of the four biotopes were also discriminated by the results of NMDS in the 2-D gradients; (4) significant differences in environmental conditions, including physicochemical and trophic conditions, were detected among biotopes, and in particular, the lateral hydrological connectivity from G1/G2 to G3 to G4 showed a clear decreasing pattern (e.g., "open" to "semi-open" to "closed"); (5) macroinvertebrate assemblage characteristics, including biodiversity and morphological and functional structures, were also found to be significantly different among biotopes, which indicated that the lateral hydrological connectivity was strongly related to diversity, structure, and function of macroinvertebrate assemblages; and (6) in the Quanji River basin, biodiversity responded to variations in lateral hydrological connectivity in a "single-valley" pattern, which was markedly distinguished from the unimodal pattern observed in lowland river systems. We argue that the hypometabolic and oligotrophic conditions in the highland river system lead to the increased sensitivity of macroinvertebrate assemblages to disturbances. Therefore, the intermediate disturbance preferred by macroinvertebrate assemblages shifts from the median connectivity environment to the low connectivity environment in highland rivers, which accounts for the "single-valley" response pattern. Conclusions Our study on bethic macroinvertebrate assemblages in different biotopes of the Quanji River has contributed considerably to our understanding of the highland invertebrates' response to variations in lateral hydrological connectivity. We find that the individual biotopes in the Quanji River respond differently to the lateral hydrological connectivity. One of the most intriguing results of our study is that biological indices, in particular the diversity index, demonstrate a single-valley response pattern to the lateral hydrological connectivity, which is in contrast with the unimodal pattern commonly observed in lowland rivers. This study not only reveals the critical roles of lateral hydrological connectivity variation in structuring highland river ecosystems from biological perspectives but also suggests that the management strategies of highland rivers should be different from those of lowland rivers.
Key words: abandoned channelbiotopetaxonomic diversityfunctional feeding groupfunctional habit groupQinghai-Tibet Plateau
青藏高原是众多大江大河的发源地，素有“亚洲水塔”之称。青藏高原的河流系统受高海拔、低气温、强辐射的影响，呈现典型的“低代谢、寡营养”特征[1]，初级生产力(如浮游藻类、大型水生植被)、次级生产力(如浮游动物、底栖动物)、生物群落的多样性和复杂度均显著低于平原河流[2-3]，因此青藏高原的河流系统对环境扰动极为敏感，对生态胁迫的抵抗能力弱，受到胁迫后恢复时间长[4]。
近年来，青藏高原的人为及自然干扰强度变化显著，影响了高原生态系统服务功能[5]，水库及闸坝修建、地下水开采、径流调节、河流改道等人类活动[6]和气候变化均会改变河流系统的水文连通性[7]，影响生物的行为习性、种群结构和演替过程，从而影响河流及滨岸区的生态系统[8]。水文连通性可定义为“物质、能量和生物体经水介导，在水循环中进行输运的能力”[9]，按照方向可分为侧向连通性、纵向连通性和垂向连通性。国内外已有研究表明，侧向水文连通性对于平原河流生态系统的影响具有规律性[10]，可用于反映流域内生物多样性和群落结构及功能的动态演变[11]，并可用于评估水利工程对河流生态系统的影响[12-13]。改变侧向水文连通性亦可作为平原河流生态系统保护和修复的重要手段[14-16]。但是，目前针对侧向水文连通性的生态效应研究集中在低海拔的平原河流系统，在“高海拔、低代谢、寡营养”的高原河流系统中，侧向水文连通性变化如何影响河流生态系统尚不明确。
本文选取青藏高原东北部青海湖的重要支流——泉吉河作为研究区域，采用大型无脊椎底栖动物(以下简称底栖动物)作为水生态指示物种，通过比较泉吉河流域内不同侧向水文连通性条件下底栖动物群落的差异，揭示侧向水文连通性变化对典型高原河流系统的生态影响，为青藏高原的河流综合管理与生态修复提供科学支撑。
1 研究区域青海湖是中国最大的内陆咸水湖泊，位于青藏高原东北部，入湖大小河流40余条，均为典型冰川发源河流[17]。泉吉河(37°12′~37°28′N，99°52′~99°55′E)位于青海湖北部，是重要的入湖河流。泉吉河流域面积567 km2，流域年平均温度－0.6 ℃，年降水量371 mm，年径流量2.4亿m3。泉吉河河道在65 km的短距离河长范围内快速演变，全河生境条件主要由河道形态控制，受温度、降水等大空间尺度因素的影响较小。泉吉河上游为顺直河道，下游则形成多流路河道并频繁发生泥沙淤积[18]，导致岔道进出口堰塞，与主河的侧向水文连通性降低，形成废弃河道[19]。2018—2020年，本文作者对泉吉河流域共49个断面(图 1a和1b)进行了底栖动物采样和栖息地生境调查。其中：2018年8月下旬调查断面15个，2019年9月中下旬调查断面18个，2020年9月上旬调查断面16个。采样时间集中于丰水期末，水文特征差异较小。22个断面位于主河道(图 1c)，27个断面位于废弃河道(图 1d)。调查断面水体pH值呈弱碱性(7.71~9.50)，溶解氧范围1.71~14.37 mg·L-1，水温范围4.4~22.7 ℃，流速范围0~1.8 m·s-1，水深范围0.07~0.92 m。
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| 图 1 研究区域示意图 |
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2 研究方法2.1 底栖动物采样与环境调查使用踢网(孔径420 μm，面积1 m×1 m)采集河床底质中的底栖动物样本。在各断面，选取3个代表性斑块进行采样，各斑块采样面积1/3 m2，汇总后即得到该断面1 m2采样结果。采集的底栖动物样本于野外进行初步分拣，并使用75%乙醇溶液固定；然后，在实验室内采用光学显微镜对样本进行鉴定至操作分类单元(operational taxonomic unit，OTU)并计数。
采样过程中使用2个采集网分别对断面颗粒有机碎屑重复采集3次。采集网1(孔径1 000 μm)仅采集粗颗粒有机碎屑(coarse particulate organic matter，CPOM，>1 mm)，采集网2(孔径10 μm)用于采集粗颗粒有机碎屑和细颗粒有机碎屑(fine particulate organic matter，FPOM，< 1 mm)。当断面的河床底质为卵砾石时，手动擦洗底质表面以采集固着藻类；当断面生长有大型水生植被时，将1 m×1 m范围内植被连根采集。底栖动物、颗粒有机碎屑、固着藻类和大型水生植被的无灰干重由干燥(105 ℃，24 h)和灰化(600 ℃，8 h)样品的质量差计算得到。
对各断面的水动力条件(流速和水深)和水质理化条件(水温、溶解氧和pH值)进行测量。其中，使用便携式声学Doppler测速仪(FlowTracker 2，SonTek，USA)测量流速和水深，使用YSI EXO水质监测平台(Xylem，USA)测量水温、溶解氧和pH值。
2.2 底栖动物-环境变化关系分析使用约束性排序分析底栖动物各物种随环境梯度的变化规律(R包“vegan”、函数“decorana”)。使用除趋势对应分析(detrended correspondence analysis，DCA) 预分析底栖动物群落对环境梯度的响应模式，当最大梯度长度超过临界长度(Lth=4) 时，使用典范对应分析(canonical correspondence analysis，CCA)进行约束性排序，否则使用冗余分析(redundancy analysis，RDA)。
2.3 底栖动物群落生境划分在主河道和废弃河道的分类基础上，使用Bray-Curtis距离计算49个断面的底栖动物群落的两两不相似性(R包“vegan”、函数“vegdist”[20])，并使用层次聚类法(R包“stats”、函数“hclust”[21]) 划分群落生境。使用非度量多维尺度分析(non-metric multidimensional scaling，NMDS；R包“vegan”、函数“metaMDS”)在二维空间中对各断面底栖动物群落进行排序，并将层次聚类和排序结果进行比较。Bray-Curtis距离DBC的计算方法为[22]
| $D_{\mathrm{BC}}=\frac{\sum\limits_{j=1}^{S_{U+V}}\left|n_{U_j}-n_{V_j}\right|}{\sum\limits_{j=1}^{S_{U+V}}\left(n_{U_j}+n_{V_j}\right)} .$ | (1) |
使用方差分析(analysis of variance，ANOVA)或Kruskal-Wallis方法，分析比较各类群落生境间环境变量、生物指数的差异显著性。使用Shapiro方法和Bartlett方法(R包“stats”、函数“Shapiro.test”和“Bartlett.test”)分别检验环境变量、生物指数的正态性和方差齐性。对于满足正态性和方差齐性的环境变量、生物指数，使用ANOVA方法检验全局差异显著性，并使用Tukey HSD方法(R包“stats”、函数“aov”和“TukeyHSD”)进行事后两两差异比较；对于不满足正态性或方差齐性的环境变量、生物指数，使用Kruskal-Wallis方法检验全局差异显著性，并使用Bonferroni方法进行事后分析(R包“agricolae”、函数“Kruskal”[24])。
2.4 底栖动物的生物指数计算采用丰度、密度、相对多度、Shannon-Wiener指数、Hilsenhoff指数等生物指数对底栖动物的多样性和群落结构进行描述。丰度指底栖动物种类数，密度指单位面积的底栖动物多度，相对多度指某类群的多度与所在群落的总多度之比，Shannon-Wiener指数H′的计算方法为[25]：
| $H^{\prime}=-\sum\limits_{i=1}^S p_i \log _2 p_i, \quad p_i=\frac{n_i}{N}.$ | (2) |
Hilsenhoff指数IH的计算方法为[27]
| $I_{\mathrm{H}}=\frac{\sum\limits_{i=1}^S n_i \cdot t_i}{N} .$ | (3) |
2.5 底栖动物的功能类群划分对底栖动物进行功能摄食类群(functional feeding group，FFG)和功能习性类群(functional habit group，FHG)划分。依据中国、北美等地研究资料[30-32]，将底栖动物按摄食器官和摄食策略划分为收集者(collector，CL)、撕食者(shredder，SH)、刮食者(scraper，SC)和捕食者(predator，PR)；依据Tachet数据库[33]和淡水生态学指南数据库(freshwaterecology.info database)[34]，将底栖动物按运动方式划分为穴居动物(burrower，BU)、攀爬动物(crawler，CR)、定植动物(settler，SE)和游泳动物(swimmer，SW)。在科级水平计算各习性类群的功能指数，再将该科所有属的功能指数进行加权平均作为该科对应的功能指数，最终得到泉吉河流域穴居、攀爬、定植、游泳动物的功能指数(分别记为IBU、ICR、ISE和ISW)。在功能指数的基础上进一步计算各习性类群的相对功能指数，如相对穴居指数(relative burrower index，RBUI)的计算方法为
| $\mathrm{RBUI}=\frac{I_{\mathrm{BU}}}{I_{\mathrm{BU}}+I_{\mathrm{CR}}+I_{\mathrm{SE}}+I_{\mathrm{SW}}} .$ | (4) |
3 结果与讨论3.1 泉吉河底栖动物及群落生境从泉吉河流域的49个断面共采集底栖动物样本122 195个，隶属于33科61属。泉吉河底栖动物群落主要由节肢动物(54属)构成，软体动物(3属)、环节动物(3属)和扁形动物(1属)种类较少。DCA结果显示最大轴长为6.48，超过临界长度4，故选用CCA分析底栖动物对环境变量的响应，结果如图 2所示。CCA的轴1与轴2的解释率分别为45.7%和19.2%，模型显著有效(P < 0.001)。底栖动物对流速、初级生产力、颗粒有机碎屑和水温的响应关系明显，其中流速表征的水动力条件与初级生产力、颗粒有机碎屑表征的营养条件呈负相关关系，共同反映侧向水文连通性变化；水温与侧向水文连通性相关性弱。不同底栖动物物种对水动力条件、营养条件的偏好差异明显。
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| 图 2 底栖动物-环境变量CCA排序结果 |
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基于底栖动物群落间的Bray-Curtis距离，使用层次聚类法将泉吉河流域49个断面(含22个主河道断面和27个废弃河道断面) 划分为4类群落生境G1—G4，如图 3a所示。NMDS结果(图 3b) 展示了49个断面的底栖动物群落在二维空间的排序分布，各类群落生境在NMDS结果中分布差异明显。
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| 图 3 泉吉河流域群落生境聚类结果 |
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3.2 群落生境的环境特征及底栖动物群落结构特征表 1展示了4类群落生境中具有显著差异的环境变量与生物指数。其中，主河道G1多数断面位于泉吉河上游，海拔相对较高，水温(5.30±1.39)℃(mean±SD，下同) 较G2[(12.50±4.36) ℃]、G3[(12.74±2.67) ℃]、G4[(11.14±4.06) ℃]等中下游断面水温显著偏低。考虑到温度对底栖动物群落结构及功能的影响较大[35]，故下文重点分析比较G2、G3和G4 3类群落生境。综合现场观测结果发现，G2中底栖动物群落均位于主河道，G3中底栖动物群落主要位于连通型废弃河道，G4中底栖动物群落主要位于半连通及封闭废弃河道，即3类群落生境的侧向水文连通性依次降低。
表 1 泉吉河4类群落生境的环境变量和生物指数
| 类型 | 环境变量及生物指数 | 检验方法 | G1 | G2 | G3 | G4 | |||||||
| 均值±标准差 | 差异显著群落① | 均值±标准差 | 差异显著群落 | 均值±标准差 | 差异显著群落 | 均值±标准差 | 差异显著群落 | ||||||
| 环境变量 | 流速/(m·s-1) | ANOVA | 0.52±0.26 | G4 | 0.79±0.39 | G3，G4 | 0.18±0.24 | G2 | 0.07±0.19 | G1，G2 | |||
| 溶解氧/(mg·L-1) | Kruskal-Wallis | 8.50±0.37 | G2，G3，G4 | 7.04±0.59 | G1 | 6.72±2.09 | G1 | 7.21±1.99 | G1 | ||||
| 水温/℃ | Kruskal-Wallis | 5.30±1.39 | G2，G3，G4 | 12.50±4.36 | G1 | 12.74±2.67 | G1 | 11.14±4.06 | G1 | ||||
| 初级生产力/(g·m-2) | Kruskal-Wallis | 0.93±0.85 | G3，G4 | 1.08±0.38 | G3，G4 | 66.54±17.95 | G1，G2，G4 | 127.77±60.28 | G1，G2，G3 | ||||
| 颗粒有机碎屑/(g·m-2) | Kruskal-Wallis | 0.40±0.15 | G3，G4 | 0.50±0.09 | G3，G4 | 49.96±24.47 | G1，G2，G4 | 130.79±92.40 | G1，G2，G3 | ||||
| 生物多样性指数 | 物种丰度 | ANOVA | 8.8±2.1 | G3 | 8.6±3.0 | G3 | 4.7±1.3 | G1，G2，G4 | 9.3±2.3 | G3 | |||
| Shannon-Wiener指数H′ | ANOVA | 1.41±0.22 | G3 | 1.26±0.49 | G3 | 0.85±0.37 | G1，G2，G4 | 1.32±0.45 | G3 | ||||
| 节肢动物门丰度 | Kruskal-Wallis | 7.5±1.9 | G3 | 8.1±2.9 | G3 | 3.9±1.1 | G1，G2，G4 | 7.4±2.3 | G3 | ||||
| 昆虫纲丰度 | ANOVA | 6±2 | G3 | 7±3 | G3 | 3±1 | G1，G2，G4 | 6±2 | G3 | ||||
| EPT②物种丰度 | ANOVA | 3.8±1.2 | G3，G4 | 3.4±1.6 | G3，G4 | 0.5±0.9 | G1，G2 | 0.8±0.6 | G1，G2 | ||||
| 摇蚊科丰度 | ANOVA | 1.6±0.5 | G4 | 1.6±0.9 | G4 | 1.4±0.7 | G4 | 3.6±1.4 | G1，G2，G3 | ||||
| 生物群落结构指数 | 生物密度/m-2 | Kruskal-Wallis | 367±237 | G4 | 235±264 | G3，G4 | 1 129±1 812 | G2，G4 | 7 752±4 550 | G1，G2，G3 | |||
| 节肢动物门相对多度/% | Kruskal-Wallis | 91±10 | 96±8 | G3, G4 | 67±31 | G2 | 84±19 | G2 | |||||
| 昆虫纲相对多度/% | Kruskal-Wallis | 81±10 | G3 | 83±15 | G3 | 37±30 | G1, G2 | 56±31 | |||||
| EPT物种相对多度/% | Kruskal-Wallis | 58±27 | G3, G4 | 61±23 | G3, G4 | 1±2 | G1, G2 | 1±1 | G1, G2 | ||||
| 摇蚊科相对多度/% | Kruskal-Wallis | 20±22 | 19±16 | G4 | 34±31 | 47±32 | G2 | ||||||
| 非昆虫纲物种相对多度/% | Kruskal-Wallis | 19±10 | G3 | 17±15 | G3 | 63±30 | G1, G2 | 44±31 | |||||
| 寡毛纲相对多度/% | Kruskal-Wallis | 9±10 | 4±8 | G3 | 33±31 | G2 | 15±19 | ||||||
| EPT/(摇蚊科+寡毛纲) | Kruskal-Wallis | 9.86±13.85 | G3，G4 | 11.33±16.44 | G3，G4 | 0.08±0.25 | G1，G2 | 0.01±0.02 | G1，G2 | ||||
| 生物群落耐污指数 | Hilsenhoff指数IH | ANOVA | 4.33±0.79 | G3，G4 | 4.34±1.13 | G3，G4 | 6.71±1.14 | G1，G2 | 6.01±0.85 | G1，G2 | |||
| 注：①经检验与该群落生境存在显著差异的其他群落生境类型(P < 0.05)；② EPT物种为蜉蝣目、積翅目、毛翅目物种统称。 | |||||||||||||
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平原河流的侧向水文连通性变化可通过水动力条件及颗粒有机碎屑滞留量来衡量[36]。侧向水文连通性越低，水动力过程越弱，颗粒有机碎屑滞留量越多。
通过对比不同侧向水文连通条件下群落生境的差异，本文发现高原河流系统中环境变量随水文连通性变化亦符合同样规律。具体而言，G2、G3、G4随水文连通性降低，流速依次减慢[G2：(0.79±0.39) m·s-1>G3：(0.18±0.24) m·s-1>G4：(0.07±0.19) m·s-1]。G2水动力过程强，氧气在水体中充分掺混，水体溶解氧较高[(7.04±0.59) mg·L-1]；G4水生植被发育，日间光合作用强，水体溶解氧亦较高[(7.21±1.99) mg·L-1]; G3水动力过程较弱且水生植被欠发育，溶解氧较低[(6.72±2.09) mg·L-1]。此外，随侧向水文连通性降低，G2、G3和G4的营养供给水平显著提高，具体表现为初级生产力增加[G2：(1.08±0.38) g·m-2 < G3：(66.54±17.95) g·m-2 < G4：(127.77±60.28) g·m-2]及颗粒有机碎屑量增加[G2：(0.50±0.09) g·m-2 < G3：(49.96±24.47) g·m-2 < G4：(130.79±92.40) g·m-2]。初级生产力增加的主要原因为多数藻类和大型水生植被偏好低流速、低浊度的静水环境以保证光合作用正常进行[37]，而颗粒有机碎屑量增加的主要原因为废弃河道水动力过程弱，主河、滨岸输入的外源性颗粒有机碎屑沉积富集[38]。此外，初级生产力的凋落物经初步分解后进一步增加了颗粒有机碎屑量。
生物指数方面，随侧向水文连通性降低，G2、G3和G4的底栖动物丰度“先降低后升高”。G3的丰度显著降低(4.7±1.3)，G2和G4的丰度差异不显著(G2：8.6±3.0；G4：9.3±2.3)；Shannon-Wiener指数的变化规律与丰度一致(G2：1.26±0.49；G3：0.85±0.37；G4：1.32±0.45)，表明泉吉河流域底栖动物多样性随侧向水文连通性降低呈“先降低后升高”的单谷式响应。此外，G2、G3、G4的底栖动物密度随侧向水文连通性降低逐渐增加[G2：(235±264) m-2 < G3：(1 129±1 812) m-2 < G4：(7 752±4 550) m-2]，符合高营养供给水平下底栖动物密度一般较高的科学认识[39]。虽然G2和G4的底栖动物多样性差异不显著，但二者的物种组成存在显著差异：G2底栖动物类群以水生昆虫为主[昆虫纲相对多度：(83±15)%]，尤其是EPT(蜉蝣目Ephemeroptera、積翅目Plecoptera、毛翅目Trichoptera)物种[EPT相对多度：(61±23)%]；而G4的底栖动物类群中水生昆虫的占比相对较低[昆虫纲相对多度：(56±31)%]，并以摇蚊科而非EPT物种为主[摇蚊科相对多度：(47±32)%]，且寡毛纲的占比相对较高[寡毛纲相对多度，G2：(4±8)% < G4：(15±19)%]。此外，G2群落生境的Hilsenhoff指数低于G4(G2：4.34±1.13 < G4：6.01±0.85)，表明废弃河道中底栖动物类群对污染的耐受能力更强，原因是G4中占优势的摇蚊属及寡毛纲物种的耐污值一般较高[40]。
3.3 群落生境的底栖动物群落功能特征表 2比较了不同群落生境中底栖动物功能类群的组成结构差异。随侧向水文连通性降低，群落生境中底栖动物总生物量逐渐增加，与初级生产力和颗粒有机碎屑的变化规律一致，且极低水文连通条件下底栖动物总生物量远高于其他群落生境[G2：(1.181±0.998) g·m-2 < G3：(1.436±2.674) g·m-2 < G4：(19.836±26.963) g·m-2]。功能摄食类群方面，收集者[G2：(0.599±0.738) g·m-2 < G3：(1.280±2.357) g·m-2 < G4：(15.245±20.580) g·m-2]和撕食者[G2：(0.004±0.014) g·m-2 < G3：(0.138±0.373) g·m-2 < G4：(0.609±1.042) g·m-2] 生物量随侧向水文连通性降低逐渐增加，这是因为较强的水动力过程会干扰颗粒有机碎屑在河道床面的富集，对收集者和撕食者的取食不利[41]；但是，收集者[G2：(50.7±73.9)%；G3：(89.1±88.1)%；G4：(76.9±76.3)%]和撕食者[G2：(0.3±1.4)%；G3：(9.6±13.9)%；G4：(3.1±3.9)%] 的相对生物量随侧向水文连通性降低呈“先升高后降低”的单峰式响应，主要因为极高、极低侧向水文连通条件下附着于卵砾石、大型水生植被表面的藻类是底栖动物的重要食物来源之一，而中等水文连通条件下颗粒有机碎屑是底栖动物的唯一食物来源；相应地，刮食者[G2：(1.7±3.3)%；G3：(0±0)%；G4：(4.1±9.2)%] 的相对生物量随侧向水文连通性降低呈单谷式响应。
表 2 泉吉河4类群落生境的功能指数
| 功能指数① | G1 | G2 | G3 | G4 | |||||||
| 均值±标准差 | 差异显著群落② | 均值±标准差 | 差异显著群落 | 均值±标准差 | 差异显著群落 | 均值±标准差 | 差异显著群落 | ||||
| 总生物量/(g·m-2) | 0.192±0.130 | G4 | 1.181±0.998 | G4 | 1.436±2.674 | G4 | 19.836±26.963 | G1，G2，G3 | |||
| CL生物量/(g·m-2) | 0.095±0.086 | G2，G3，G4 | 0.599±0.738 | G1，G4 | 1.280±2.357 | G1，G4 | 15.245±20.580 | G1，G2，G3 | |||
| SH生物量/(g·m-2) | 0.000±0.001 | G4 | 0.004±0.014 | G4 | 0.138±0.373 | G4 | 0.609±1.042 | G1，G2，G3 | |||
| SC生物量/(g·m-2) | 0.061±0.058 | G3，G4 | 0.020±0.033 | G3 | 0.000±0.000 | G1，G2 | 0.805±2.473 | G1 | |||
| PR生物量/(g·m-2) | 0.036±0.045 | G4 | 0.558±0.624 | G3 | 0.018±0.030 | G2，G4 | 2.661±5.693 | G1，G3 | |||
| 穴居指数IBU | 22.7±11.8 | G4 | 16.4±17.5 | G3，G4 | 102.0±164.2 | G2，G4 | 927.8±821.6 | G1，G2，G3 | |||
| 爬行指数ICR | 221.7±143.0 | G4 | 1 904.0±89.0 | G3，G4 | 579.6±847.1 | G2，G4 | 4 429.1±2 878.9 | G1，G2，G3 | |||
| 定植指数ISE | 14.3±7.2 | G4 | 4.8±3.4 | G3，G4 | 79.9±148.8 | G2，G4 | 706.2±720.5 | G1，G2，G3 | |||
| 游泳指数ISW | 108.2±93.7 | G4 | 108.0±157.0 | G4 | 374.4±913.8 | G4 | 2 294.4±2 627.7 | G1，G2，G3 | |||
| 相对穴居指数RBUI | 0.07±0.04 | 0.08±0.03 | 0.11±0.05 | 0.12±0.06 | |||||||
| 相对爬行指数RCRI | 0.61±0.04 | G2 | 0.52±0.14 | G1 | 0.56±0.05 | 0.53±0.11 | |||||
| 相对定植指数RSEI | 0.04±0.04 | 0.04±0.03 | G4 | 0.07±0.06 | 0.09±0.06 | G2 | |||||
| 相对游泳指数RSWI | 0.28±0.11 | 0.36±0.15 | 0.27±0.15 | 0.26±0.21 | |||||||
| 注：①功能摄食类群包括CL(收集者collector)、SH(撕食者shredder)、SC(刮食者scraper)、PR(捕食者predator)；②经Kruskal-Wallis检验与该群落生境存在显著差异的其他群落生境类型(P < 0.05)。 | |||||||||||
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功能习性类群方面，随侧向水文连通性降低，群落生境中功能指数IBU、ISE、RBUI和RSEI均逐渐增大。其中，IBU和RBUI随侧向水文连通性降低而增大的主要原因为低连通条件下废弃河道的静水环境为穴居型底栖动物提供了适宜厚度的泥沙淤积层[42]；ISE和RSEI随侧向水文连通性降低而增大的原因则为低水动力强度的废弃河道床面稳定，泥沙输移过程弱，有利于定植生物进行附着[43]。RSWI随侧向水文连通性降低而逐渐减小，表明低连通条件下，群落生境对底栖动物游泳能力的环境筛选减弱，适宜游泳动物的原有生态位被其他运动类型动物取代；RCRI呈现单峰式响应，可能是由于：随侧向水文连通性降低，适宜游泳动物的生态位条件逐渐转变为适宜定植动物的生态位条件，而在中等侧向水文连通条件下，生态位被攀爬动物临时占据。
表 2结果表明，侧向水文连通性主要改变河流系统的水动力条件[6]和营养供给水平[44]，从而对底栖动物群落形态结构和功能产生影响。水动力条件方面，侧向水文连通性降低造成河流系统由流水环境向静水环境转变，对不同功能习性的底栖动物进行筛选，如攀爬动物由于生活在底质表面或沉水植物叶面上，游动能力弱，无法在急流中生存[32]；营养供给水平方面，静水环境的初级生产力和颗粒有机碎屑量均高于流水环境，造成了群落生境的营养水平差异，从而影响了底栖动物的功能摄食结构，如当废弃河道远离主河道时，受到的水流扰动少，造成水生植物生物量增加，刮食型和撕食型动物比例相应增加[45-47]。
3.4 高原与平原河流对侧向水文连通性的响应差异针对南美洲亚马孙河[48]、意大利塔利亚门托河[49]、波兰斯卢皮亚河[50]、中国长江[51]等低海拔平原河流的研究表明，底栖动物多样性对侧向水文连通性的变化呈现单峰式响应，即在中等侧向水文连通性时达到峰值。图 4虚线定量地给出了多瑙河、长江下游流域底栖动物多样性随侧向水文连通性的单峰式变化规律。因此，在进行平原河流生态修复时常把恢复废弃河道与主河道的水文连通性作为重要策略之一，并取得了较好效果[43, 52]。利用中度干扰假说[53-54]可以较好地解释底栖动物多样性与侧向水文连通性的单峰响应关系——高侧向水文连通性带来的强水动力干扰会影响大多数底栖动物的生存，造成多样性下降，低侧向水文连通性则会导致少数物种成为优势种，从而抑制底栖动物整体的多样性[55]，因此过高或过低的极端侧向水文连通条件对于底栖动物多样性均是不利的。中等侧向水文连通性能为底栖动物提供较多生态位，且适当的干扰亦有效避免了单一物种的极端优势，从而有利于增加物种多样性。
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| 图 4 底栖动物丰度对侧向水文连通性的响应模式 |
| 图选项 |
但是，在泉吉河这一高原河流系统中，本文作者观察到底栖动物多样性对水文连通性的变化呈现出与平原河流截然相反的“单谷响应”模式，类似结果在黄河源区河流亦有报道[56-57](图 4实线)。本文作者认为，中度干扰假说对于高原河流系统仍然适用，但使高原河流底栖动物多样性达到峰值的中度干扰，应当发生在低侧向水文连通河道(如封闭废弃河道)而非中等连通河道(如开放废弃河道)中。造成“单谷响应”的主要原因为，底栖动物群落的多样性和组成受到高原河流系统“低代谢、寡营养”生态本底的强烈影响[1]。高原河流系统温度低，辐射强，营养来源少，造成底栖动物代谢减慢，种间互作对称性增强，群落复杂度降低，群落抵抗力和恢复力减弱[58]。因此，高原河流系统中的底栖动物群落较平原河流对侧向水文连通性增加产生的水动力扰动更为敏感，受到扰动后亦需更长时间进行恢复[59]。
4 结论基于泉吉河流域的底栖动物采样、河流地貌测量及协同分析，识别了4类典型群落生境G1—G4。主河道中的群落生境G1和G2侧向水文连通性高，连通型废弃河道中的群落生境G3侧向水文连通性中等，半连通及封闭废弃河道中的群落生境G4侧向水文连通性低。通过对各项环境指标和生物指标的统计和分析，本研究揭示了侧向水文连通性对典型高原河流系统中底栖动物群落的影响规律及机理，得到以下结论：
1) 侧向水文连通性改变了泉吉河流域的局部水动力过程和营养供给水平，在不同连通性条件下，底栖动物群落的多样性、结构和功能特征存在显著差异。
2) 泉吉河流域的底栖动物多样性随侧向水文连通性变化呈“先降低后升高”的单谷式响应，与平原河流中常见的“单峰式响应”模式差异明显，表明高原河流系统中中度干扰假说可能发生于低侧向水文连通而非中等侧向水文连通条件下。
3) 高原河流底栖动物群落受“低代谢、寡营养”条件影响显著，对干扰极为敏感，使多样性最优的中度干扰条件由中等侧向水文连通向低侧向水文连通偏移，这是造成底栖动物多样性单谷式响应侧向水文连通性变化的重要原因。
本研究为开展高原河流系统的流域综合管理及生态修复工作提供了依据。然而，本研究案例局限于青藏高原东北部典型流域，并重点关注底栖动物群落，未能在青藏高原尺度上进行复杂生物类群的综合分析，在解释底栖动物多样性响应机理时亦未充分考虑水文要素(例如，高原冻土区地下水补给等)的潜在影响。未来应增加对不同生物类群(例如，藻类、浮游动物、鱼类等)的针对性研究和整体研究，同步补充采样点的水文类指标监测，并拓展研究区域范围进行案例比较，以提高研究结果的完备性和普适性。
参考文献
| [1] | XU M Z, ZHAO N, ZHOU X D, et al. Macroinvertebrate biodiversity trends and habitat relationships within headwater rivers of the Qinghai-Tibet Plateau[J]. Water, 2018, 10(9): 1214. DOI:10.3390/w10091214 |
| [2] | XU M Z, WANG Z Y, PAN B Z, et al. The assemblage characteristics of benthic macroinvertebrates in the Yalutsangpo River, the highest major river in the world[J]. Frontiers of Earth Science, 2014, 8(3): 351-361. DOI:10.1007/s11707-014-0414-2 |
| [3] | 韩谞. 长江源区浮游生物沿海拔梯度的群落分布格局及驱动力分析[D]. 西安: 西安理工大学, 2021. HAN X. Distribution patterns and driving forces of plankton communities along elevational gradients in the Yangtze River source region[D]. Xi'an: Xi'an University of Technology, 2021. (in Chinese) |
| [4] | MAIOLINI B, LENCIONI V. Longitudinal distribution of macroinvertebrate assemblages in a glacially influenced stream system in the Italian Alps[J]. Freshwater Biology, 2001, 46(12): 1625-1639. DOI:10.1046/j.1365-2427.2001.00849.x |
| [5] | HUANG K, ZHANG Y J, ZHU J T, et al. The influences of climate change and human activities on vegetation dynamics in the Qinghai-Tibet Plateau[J]. Remote Sensing, 2016, 8(10): 876. DOI:10.3390/rs8100876 |
| [6] | BRACKEN L J, CROKE J. The concept of hydrological connectivity and its contribution to understanding runoff-dominated geomorphic systems[J]. Hydrological Processes, 2007, 21(13): 1749-1763. DOI:10.1002/hyp.6313 |
| [7] | 方佳佳, 王烜, 孙涛, 等. 河流连通性及其对生态水文过程影响研究进展[J]. 水资源与水工程学报, 2018, 29(2): 19-26. FANG J J, WANG X, SUN T, et al. Review of research on river connectivity and its impact on eco-hydrological process[J]. Journal of Water Resources and Water Engineering, 2018, 29(2): 19-26. (in Chinese) |
| [8] | ZHANG Y H, HUANG C Y, ZHANG W Q, et al. The concept, approach, and future research of hydrological connectivity and its assessment at multiscales[J]. Environmental Science and Pollution Research, 2021, 28(38): 52724-52743. DOI:10.1007/s11356-021-16148-8 |
| [9] | FREEMAN M C, PRINGLE C M, JACKSON C R. Hydrologic connectivity and the contribution of stream headwaters to ecological integrity at regional scales[J]. Journal of the American Water Resources Association, 2007, 43(1): 5-14. DOI:10.1111/j.1752-1688.2007.00002.x |
| [10] | AMOROS C, BORNETTE G. Connectivity and biocomplexity in waterbodies of riverine floodplains[J]. Freshwater Biology, 2002, 47(4): 761-776. DOI:10.1046/j.1365-2427.2002.00905.x |
| [11] | THOMAZ S M, BINI L M, BOZELLI R L. Floods increase similarity among aquatic habitats in river-floodplain systems[J]. Hydrobiologia, 2007, 579(1): 1-13. DOI:10.1007/s10750-006-0285-y |
| [12] | WU Y A, ZHANG Y H, DAI L Y, et al. Hydrological connectivity improves soil nutrients and root architecture at the soil profile scale in a wetland ecosystem[J]. Science of the Total Environment, 2021, 762: 143162. DOI:10.1016/j.scitotenv.2020.143162 |
| [13] | BAO W H, ZENG X Y, LUO C Y, et al. The relationship between hydrological connectivity changes inside and outside biodiversity hotspots and its implication for sustainable environmental management[J]. Sustainability, 2022, 14(11): 6654. DOI:10.3390/su14116654 |
| [14] | 王新艳, 闫家国, 白军红, 等. 黄河口滨海湿地水文连通对大型底栖动物生物连通的影响[J]. 自然资源学报, 2019, 34(12): 2544-2553. WANG X Y, YAN J G, BAI J H, et al. Influence of hydrological connectivity of coastal wetland on the biological connectivity of macrobenthos in the Yellow River Estuary[J]. Journal of Natural Resources, 2019, 34(12): 2544-2553. (in Chinese) |
| [15] | 张仲胜, 于小娟, 宋晓林, 等. 水文连通对湿地生态系统关键过程及功能影响研究进展[J]. 湿地科学, 2019, 17(1): 1-8. ZHANG Z S, YU X J, SONG X L, et al. Impacts of hydrological connectivity on key ecological processes and functions in wetlands: A general review[J]. Wetland Science, 2019, 17(1): 1-8. DOI:10.13248/j.cnki.wetlandsci.2019.01.001 (in Chinese) |
| [16] | 冯久格, 李谦维, 梁晨, 等. 基于景观指数的黄河口湿地水文连通动态分析[J]. 北京师范大学学报(自然科学版), 2021, 57(1): 12-21. FENG J G, LI Q W, LIANG C, et al. Landscape index analysis of hydrological connectivity dynamics in the Yellow River Delta[J]. Journal of Beijing Normal University (Natural Science), 2021, 57(1): 12-21. (in Chinese) |
| [17] | 中国科学院兰州地质研究所, 中国科学院水生生物研究所, 中国科学院微生物研究所. 青海湖综合考察报告[M]. 北京: 科学出版社, 1979. Lanzhou Institute of Geology, Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Institute of Microbiology, Chinese Academy of Sciences. An report on comprehensive exploration of Qinghai Lake[M]. Beijing: Science Press, 1979. (in Chinese) |
| [18] | LIU Z B, SHANG Y Z, ZHAO R S, et al. Formation mechanism and sedimentary pattern of abandoned channels[J]. Acta Geologica Sinica (English Edition), 2020, 94(2): 545-555. DOI:10.1111/1755-6724.14330 |
| [19] | CONSTANTINE J A, MCLEAN S R, DUNNE T. A mechanism of chute cutoff along large meandering rivers with uniform floodplain topography[J]. Geological Society of America Bulletin, 2010, 122(5-6): 855-869. DOI:10.1130/B26560.1 |
| [20] | OKSANEN J, BLANCHET F G, KINDT R, et al. vegan: Community ecology package[Z/OL]. [2022-10-15]. R package version 2.5-7, 2020. https://CRAN.R-project.org/package=vegan. |
| [21] | R Core Team. R: A language and environment for statistical computing. R foundation for statistical computing[Z/OL]. [2022-10-15]. Vienna, Austria, 2018. https://www.gbif.org/tool/81287/r-a-language-and-environment-for-statistical-computing. |
| [22] | BRAY J R, CURTIS J T. An ordination of the upland forest communities of southern Wisconsin[J]. Ecological Monographs, 1957, 27(4): 325-349. DOI:10.2307/1942268 |
| [23] | RICOTTA C, PODANI J. On some properties of the Bray-Curtis dissimilarity and their ecological meaning[J]. Ecological Complexity, 2017, 31: 201-205. DOI:10.1016/j.ecocom.2017.07.003 |
| [24] | DE MENDIBURU F. agricolae: Statistical procedures for agricultural research[Z/OL]. (2021-06-06)[2022-10-15]. R package version 1.3-5. https://CRAN.R-project.org/package=agricolae. |
| [25] | GRAY J S. The measurement of marine species diversity, with an application to the benthic fauna of the Norwegian continental shelf[J]. Journal of Experimental Marine Biology and Ecology, 2000, 250(1-2): 23-49. DOI:10.1016/S0022-0981(00)00178-7 |
| [26] | SPELLERBERG I F, FEDOR P J. A tribute to Claude Shannon (1916—2001) and a plea for more rigorous use of species richness, species diversity and the "Shannon-Wiener" index[J]. Global Ecology and Biogeography, 2003, 12(3): 177-179. DOI:10.1046/j.1466-822X.2003.00015.x |
| [27] | HILSENHOFF W L. An improved biotic index of organic stream pollution[J]. Great Lakes Entomologist, 1987, 20(1): 31-39. |
| [28] | HILSENHOFF W L. Seasonal correction factors for the biotic index[J]. Great Lakes Entomologist, 1988, 21(1): 9-13. |
| [29] | PASSY S I, BODE R W, CARLSON D M, et al. Comparative environmental assessment in the studies of benthic diatom, macroinvertebrate, and fish communities[J]. International Review of Hydrobiology, 2004, 89(2): 121-138. DOI:10.1002/iroh.200310721 |
| [30] | CUMMINS K W, KLUG M J. Feeding ecology of stream invertebrates[J]. Annual Review of Ecology and Systematics, 1979, 10: 147-172. DOI:10.1146/annurev.es.10.110179.001051 |
| [31] | BARBOUR M T, GERRITSEN J, SNYDER B D, et al. Rapid bioassessment protocols for use in streams and wadeable rivers: Periphyton, benthic macroinvertebrates, and fish. EPA 841-B-99-002[S]. Washington DC: U.S. Environmental Protection Agency, 1999. |
| [32] | 段学花, 王兆印, 徐梦珍. 底栖动物与河流生态评价[M]. 北京: 清华大学出版社, 2010. DUAN X H, WANG Z Y, XU M Z. Benthic macroinvertebrate and application in the assessment of stream ecology[M]. Beijing: Tsinghua University Press, 2010. (in Chinese) |
| [33] | USSEGLIO-POLATERA P, BOURNAUD M, RICHOUX H, et al. Biological and ecological traits of benthic freshwater macroinvertebrates: Relationships and definition of groups with similar traits[J]. Freshwater Biology, 2000, 43(2): 175-205. DOI:10.1046/j.1365-2427.2000.00535.x |
| [34] | SCHMIDT-KLOIBER A, HERING D. www.freshwater ecology.info: An online tool that unifies, standardises and codifies more than 20, 000 European freshwater organisms and their ecological preferences[J]. Ecological Indicators, 2015, 53: 271-282. DOI:10.1016/j.ecolind.2015.02.007 |
| [35] | HEINO J, VIRKKALA R, TOIVONEN H. Climate change and freshwater biodiversity: Detected patterns, future trends and adaptations in northern regions[J]. Biological Reviews, 2009, 84(1): 39-54. DOI:10.1111/j.1469-185X.2008.00060.x |
| [36] | LARSEN L G, CHOI J, NUNGESSER M K, et al. Directional connectivity in hydrology and ecology[J]. Ecological Applications, 2012, 22(8): 2204-2220. DOI:10.1890/11-1948.1 |
| [37] | WARD J V, TOCKNER K, SCHIEMER F. Biodiversity of floodplain river ecosystems: Ecotones and connectivity[J]. River Research and Applications, 1999, 15(1-3): 125-139. |
| [38] | TOCKNER K, PENNETZDORFER D, REINER N, et al. Hydrological connectivity, and the exchange of organic matter and nutrients in a dynamic river-floodplain system (Danube, Austria)[J]. Freshwater Biology, 1999, 41(3): 521-535. DOI:10.1046/j.1365-2427.1999.00399.x |
| [39] | DE SOUZA REZENDE R, KROTH N, CAPITANIO B M, et al. Abiotic factors and trophic interactions affect the macroinvertebrate community of bromeliad tanks in a Neotropical Restinga[J]. Limnology, 2020, 21(3): 275-285. DOI:10.1007/s10201-020-00614-2 |
| [40] | EXTENCE C A, FERGUSON A J D. Aquatic invertebrate surveys as a water quality management tool in the Anglian Water region[J]. Regulated Rivers: Research and Management, 1989, 4(2): 139-146. DOI:10.1002/rrr.3450040206 |
| [41] | PANDEY C K, MISHRA A S. Longitudinal patterns of benthic macroinvertebrate fauna in river Dhasan, Central India[J]. Applied Biological Research, 2021, 23(4): 331-340. DOI:10.5958/0974-4517.2021.00043.4 |
| [42] | BOULTON A J. Hyporheic rehabilitation in rivers: Restoring vertical connectivity[J]. Freshwater Biology, 2007, 52(4): 632-650. DOI:10.1111/j.1365-2427.2006.01710.x |
| [43] | CUMMINS K W, MERRITT R W, ANDRADE P C N. The use of invertebrate functional groups to characterize ecosystem attributes in selected streams and rivers in south Brazil[J]. Studies on Neotropical Fauna and Environment, 2005, 40(1): 69-89. DOI:10.1080/01650520400025720 |
| [44] | REID M A, DELONG M D, THOMS M C. The influence of hydrological connectivity on food web structure in floodplain lakes[J]. River Research and Applications, 2012, 28(7): 827-844. DOI:10.1002/rra.1491 |
| [45] | MONAGHAN M T, ROBINSON C T, SPAAK P, et al. Macroinvertebrate diversity in fragmented alpine streams: Implications for freshwater conservation[J]. Aquatic Sciences, 2005, 67(4): 454-464. DOI:10.1007/s00027-005-0787-0 |
| [46] | S?RBU A, JANAUER G, SCHMIDT-MUMM U, et al. Characterisation of the potamal Danube River and the Delta: Connectivity determines indicative macrophyte assemblages[J]. Hydrobiologia, 2011, 671(1): 75-93. DOI:10.1007/s10750-011-0705-5 |
| [47] | KERUZORé A A, WILLBY N J, GILVEAR D J. The role of lateral connectivity in the maintenance of macrophyte diversity and production in large rivers[J]. Aquatic Conservation: Marine and Freshwater Ecosystems, 2013, 23(2): 301-315. DOI:10.1002/aqc.2288 |
| [48] | PAILLEX A, CASTELLA E, CARRON G. Aquatic macroinvertebrate response along a gradient of lateral connectivity in river floodplain channels[J]. Journal of the North American Benthological Society, 2007, 26(4): 779-796. DOI:10.1899/06-12.1 |
| [49] | ARSCOTT D B, TOCKNER K, WARD J V. Lateral organization of aquatic invertebrates along the corridor of a braided floodplain river[J]. Journal of the North American Benthological Society, 2005, 24(4): 934-954. DOI:10.1899/05-037.1 |
| [50] | OBOLEWSKI K. Macrozoobenthos patterns along environmental gradients and hydrological connectivity of oxbow lakes[J]. Ecological Engineering, 2011, 37(5): 796-805. DOI:10.1016/j.ecoleng.2010.06.037 |
| [51] | 潘保柱, 王海军, 梁小民, 等. 长江故道底栖动物群落特征及资源衰退原因分析[J]. 湖泊科学, 2008, 20(6): 806-813. PAN B Z, WANG H J, LIANG X M, et al. Macrozoobenthos in Yangtze oxbows: Community characteristics and causes of resources decline[J]. Journal of Lake Sciences, 2008, 20(6): 806-813. DOI:10.3321/j.issn:1003-5427.2008.06.017 (in Chinese) |
| [52] | PAILLEX A, DOLéDEC S, CASTELLA E, et al. Large river floodplain restoration: Predicting species richness and trait responses to the restoration of hydrological connectivity[J]. Journal of Applied Ecology, 2009, 46(1): 250-258. DOI:10.1111/j.1365-2664.2008.01593.x |
| [53] | CONNELL J H. Diversity in tropical rain forests and coral reefs: High diversity of trees and corals is maintained only in a nonequilibrium state[J]. Science, 1978, 199(4335): 1302-1310. DOI:10.1126/science.199.4335.1302 |
| [54] | WORM B, DUFFY J E. Biodiversity, productivity and stability in real food webs[J]. Trends in Ecology & Evolution, 2003, 18(12): 628-632. |
| [55] | ROXBURGH S H, SHEA K, WILSON J B. The intermediate disturbance hypothesis: Patch dynamics and mechanisms of species coexistence[J]. Ecology, 2004, 85(2): 359-371. DOI:10.1890/03-0266 |
| [56] | 周雄冬. 青藏高原底栖动物对河流地貌的响应研究[D]. 北京: 清华大学, 2019. ZHOU X D. Study on the responses of macroinvertebrate assemblages to river geomorphology in the Qinghai-Tibet Plateau[D]. Beijing: Tsinghua University, 2019. (in Chinese) |
| [57] | 侯易明. 黄河源区白河流域底栖动物对河流演变的响应研究[D]. 西安: 西安理工大学, 2021. HOU Y M. The response of benthic macroinvertebrate to the fluvial processes of meandering rivers in Baihe River Basin in the source region of the Yellow River[D]. Xi'an: Xi'an University of Technology, 2021. (in Chinese) |
| [58] | ZHOU X D, XU M Z, WANG Z Y, et al. Responses of macroinvertebrate assemblages to environmental variations in the river-oxbow lake system of the Zoige wetland (Bai River, Qinghai-Tibet Plateau)[J]. Science of the Total Environment, 2019, 659: 150-160. DOI:10.1016/j.scitotenv.2018.12.310 |
| [59] | ASCHALEW L, MOOG O. Benthic macroinvertebrates based new biotic score "ETHbios" for assessing ecological conditions of highland streams and rivers in Ethiopia[J]. Limnologica, 2015, 52: 11-19. DOI:10.1016/j.limno.2015.02.002 |
