KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 多尺度协同的塔里木河荒漠河岸林植被的水文响应研究 | |
| Alternative Title | Study on Vegetation-Hydrological Response of Desert Riparian Forest in Tarim River at Multi-scale |
| 张广朋 | |
| Subtype | 博士 |
| Thesis Advisor | 徐新文 ; 徐海量 |
| 2020-09-30 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 北京 |
| Degree Discipline | 理学博士 |
| Keyword | 荒漠河岸林 地下水 多尺度 稳定同位素 植物功能性状 Desert riparian forest Groundwater Multiscale Stable isotope Plant functional traits |
| Abstract | 在与干旱区河流水文变化过程的长期适应过程中，荒漠河岸林植被繁育更新、群落演替及分布格局与河流水系变迁形成了不可分割的密切关系，因此，深刻理解多尺度下的荒漠河岸林与水文过程的协同适应机制成为开展生态保护最为关键的科学基础。 本文针对不同水文过程下荒漠河岸林多尺度协同适应过程的关键科学问题，借助树轮年表构建、稳定同位素及植物功能性状等多种技术方法，以水资源转移转化过程为主线，从器官、物种（个体）、群落到区域尺度，利用大量的、连续长时间的、丰富的实地调查及实验数据，定量厘清了河道渗漏及生态闸放水对荒漠河岸林生长的贡献，明确了荒漠河岸林群落的水分来源及利用效率等适应机制，从环境筛选和生态位分化的角度研究了地下水变化下荒漠河岸林多样性维持和分异机制，揭示了连续长时间漫溢干扰下群落多样性的演替规律。同时，提出了针对塔里木河干流促进荒漠河岸林生长的生态水利工程合理调控措施，以及塔里木河下游实现荒漠河岸林保护和修复的地表水-地下水干扰模式。研究的开展不仅丰富干旱区生态水文研究，更为塔里木河生态调度及荒漠河岸林生态保育提供了重要的技术参考和科学理论依据。研究结果表明：（1）河道耗水量和生态闸放水量的峰值与地下水埋深的谷值存在一致性，生态闸放水对抬升地下水埋深，进而促进植被生长起到关键作用。其中，胡杨树干生长与生态闸放水量的相关性较好，而地下水埋深是促进冠层生长的关键因子生态水利工程修建以后，虽然耗水量比修建前减少了 12.4%；而树轮年表和TINDVI（累计植被指数） 分别增加了 5.6%和 4.2%，这表明生态水利工程促进了植物生长需水与供水（即生态闸放水和地下水埋深变化）的过程耦合，提高了植物生长对水资源的利用效率。 此外， 从生态水高效利用的角度， 当塔里木河径流量大于 43.1×108m3 时，应通过生态闸对天然植被进行引水漫溢。（2） 随着地下水埋深的增加， 胡杨幼林水分来源由集中到分散， 其它林龄胡杨的水分来源均能随地下水埋深的增加逐步下移，且当地下水超过 5m 时，其他林龄胡杨对浅层土壤水的利用率明显下降，避免了与胡杨幼林的水分竞争。 多枝柽柳水分来源呈现出“聚集-分散”的分布特点，罗布麻、 胀果甘草及芦苇更多的利用接近于相对深层的土壤水（贡献率超过 60%）。 在地下水 2~3m、 3~4m 和4~5m 埋深下，随着胡杨林龄的增加，其水分利用效率逐步减小，在地下水 5~6m埋深下过熟林显著小于其他林龄胡杨水分利用效率。在 4~5m 地下水埋深下荒漠河岸林在个体和群落尺度水分利用效率均达到最大值， 存在明显的中度干扰效应，与胡杨相比，灌木、半灌木及多年生草本其在变化水分条件下生长过程较为稳定。（3） 地下水埋深和土壤盐分含量共同主导了荒漠河岸林的物种多样性，地下水埋深增加和土壤盐分含量的降低均可提升其物种多样性水平。 塔里木河下游物种在地下水埋深和盐分浓度生境变幅上存在较大差异， 多枝柽柳及胡杨所适应的地下水埋深和土壤盐分浓度生境范围均最大，相较于土壤盐分浓度，其他物种对地下水埋深的适应生境范围相对较小。干旱和盐分胁迫维持其群落内 LN（叶氮含量）、 LP（叶磷含量） 和 SLA（比叶面积） 性状的功能多样性，与盐分胁迫相比，地下水埋深下降导致的干旱胁迫更容易影响到植物性状的功能多样性，地下水埋深对功能性状平均值具有较强的直接正效应，对群落功能性状距离有较强的间接负效应。（4） 生态输水为塔里木河下游荒漠河岸林生态系统的保护（补给地下水和土壤水水量占输水量的 44.5%和 42.6%）和恢复（用于漫溢的水量占 4.9%）提供了丰沛的水源。强度和轻度的漫溢干扰将促进植物分别演替成对干旱胁迫抗性较差的芦苇群落和花花柴群落。在中度漫溢干扰下（1 年 1~2 次，每次持续时间20~30d），植物形成了物种多样的（最大多样性指数）、以乔灌木为建群种（最大重要值）的植物群落。 为促进荒漠河岸林的生长和恢复， 在荒漠河岸林生态系统恢复的初期，对退化区实施中度漫溢干扰，地下水埋深由>7m 减小至 2~4m。此后，基于生态系统的保护和水资源的高效利用，植物群落的干扰模式应维持 4~5m的地下水埋深，至少实现 2~3 年 1 次、持续时间 20-30d 的地表水漫溢。若干旱加剧，为避免生态系统受损严重，可将地下水埋深维持在 5~7m，此时水力分配可在一定的程度弥补植物群落的生态水亏缺。 |
| Other Abstract | In arid inland river basin, vegetation growth and regeneration, communitysuccession and distribution pattern of desert riparian forest have formed a significantlyrelevant relationship with hydrological process. Therefore, it is the most importantscientific basis for ecological protection to deeply study the collaboration adaptationmechanism of desert riparian forest and hydrological process. This paper focus on thekey scientific problem of multi-scale coordinated adaptation process of the desertriparian forest with the hydrological processes. From organ, species (individual),groups to regional scale, the adaptive mechanism of desert riparian forest underdifferent hydrological processes was studied by using the method of tree-ringchronology, stable isotopes, and plant functional traits, etc., based on a large number offield survey and experimental data. Firstly, we quantitatively clarify the contribution ofriver leakage and ecological sluice water discharge to the growth of desert riparianforests. Then, the adaptive mechanism of desert riparian forest community such aswater source and utilization efficiency were also studied. And, the diversitymaintenance and differentiation mechanism of desert riparian forest under groundwaterchange, and the succession law of community diversity under continuous long-termflooding interference were revealed. Meanwhile, this paper put forward the reasonablecontrol measures of ecological water conservancy project to promote the growth ofdesert riparian forest in the main stream of Tarim River, and the surface watergroundwater interference mode to realize the protection and restoration of desertriparian forest in the lower reaches of Tarim River. The results show that:(1) The peak value of river water consumption and ecological sluice waterdischarge was consistent with the valley value of groundwater depth. Ecological sluicewater discharge played a key role in raising groundwater depth and promotingvegetation growth. Furthermore, there was a good correlation between the growth of Populus euphratica trunk and the discharge of ecological sluice. And, the groundwaterdepth was the key factor to promote the growth of canopy. After the construction ofecological water conservancy project, although the water consumption decreased by12.4%, the tree-ring chronology and TINDVI increased by 5.6% and 4.2% respectively,which indicated that the ecological water conservancy project promoted the couplingof plant growth water demand and water supply (that is, changes of ecological sluicewater discharge and groundwater depth), and improved the utilization efficiency ofplant growth on water resources. Meanwhile, we advised that, when the runoff of TarimRiver was greater than 43.1 × 108m3, the natural vegetation should be diverted andflooded through ecological sluice.(2) With the increase of groundwater depth, the water sources of young Populuseuphratica changed from “concentrative” to “disperse”, and the water sources of P.euphratica of other ages could gradually move down. When the groundwater exceeded5 m, the utilization rate of shallow soil water of other age P. euphratica of other agesdecreased significantly, avoiding the water competition with young P. euphratica. Thewater sources of Tamarix ramosissima showed the distribution characteristics of"aggregation-dispersion". Apocynum venetum, Glycyrrhiza inflata and Phragmitesaustralis used more soil water close to the deeper layer (contribution rate was morethan 60%). Under the depth of 2-3m, 3-4m and 4-5m, the water use efficiency of P.euphratica decreased gradually with the increase of stand age, and the water useefficiency of over mature forest was significantly lower than that of other ages under 5-6m. At the depth of 4-5m, the desert riparian forest reached its maximum water useefficiency at both individual and community scales, with obvious moderate disturbanceeffect. Compared with P. euphratica, the growth process of shrubs, sub-shrubs andperennial herbs was more stable under changing water conditions.(3) The species diversity of desert riparian forest is dominated by groundwaterdepth and soil salt content. The increase of groundwater depth and the decrease of soilsalt content can enhance the species diversity. There were great differences in thehabitat range of groundwater depth and salt concentration among species in the lower reaches of Tarim River. T. ramosissima and P. euphratica had the largest habitat rangeof groundwater depth and soil salt concentration. Compared with soil salt concentration,other species had relatively small habitat range for groundwater depth. Drought and saltstress maintained the functional diversity of LN (leaf nitrite), LP (leaf phosphorus) andSLA (specific leaf area) characters in the community. Compared with salt stress,drought stress caused by the decline of groundwater depth was more likely to affect thefunctional diversity of plant traits. Groundwater depth had a strong direct positive effecton the average value of functional traits, and had a strong indirect negative effect onthe distance of functional traits.(4) Ecological water conveyance provided abundant water resources for theprotection (replenishment of groundwater and soil water accounted for 44.5% and 42.6%of ecological water conveyance) and restoration (4.9% of water used for flooding) ofdesert riparian forest ecosystem in the lower reaches of Tarim River. Strong and mildflooding disturbance could promote plant succession to Ph. australis community andKarelinia caspica community with poor drought resistance. Under moderate floodingdisturbance (gradient: 1 ~ 2 times a year, lasting for 20 ~ 30 days each time), plants hadformed a plant community with diverse species (maximum diversity index), with treesand shrubs as constructive species (maximum important value). In order to promote thegrowth and restoration of desert riparian forest ecosystem, moderate floodingdisturbance was carried out in the early stage of desert riparian forest ecosystemrestoration, and the groundwater depth was reduced from > 7m to 2 ~ 4m. Since then,based on the protection of the ecosystem and the efficient use of water resources, thedisturbance mode of the plant community should maintain the groundwater depth of4~5m, and achieve surface water flooding at least once in 2~3 years. If the droughtintensified, in order to avoid serious damage to the ecosystem, the groundwater depthcan be maintained at 5 ~ 7m, and the hydraulic distribution could make up for theecological water deficit of the plant community to a certain extent. |
| Subject Area | 生态学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/15407 |
| Collection | 中国科学院新疆生态与地理研究所 研究系统 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 张广朋. 多尺度协同的塔里木河荒漠河岸林植被的水文响应研究[D]. 北京. 中国科学院大学,2020. |
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