1998年特大洪水前后霍林河流域下游洪泛湿地景观变化研究

以1998年特大历史洪水为背景,基于遥感技术平台,运用景观生态学理论,从时间尺度上进行单场洪水前后洪泛湿地景观格局的定量对比分析研究,通过特大历史洪水前后的景观动态变化、景观格局指数变化和景观转换变化三方面来揭示特大历史洪水对退化洪泛湿地景观的恢复功效.结果表明:(1)霍林河1998年特大历史洪水对流域下游退化的洪泛湿地具有很好的恢复功效,且以自然湿地有恢复效应较强,人工湿地的作用效果甚微.(2)在特大历史洪水作用下霍林河流域下游洪泛湿地景观整体性和多样性提升,稳定性增强.(3)霍林河1998年特大历史洪水促进数量众多的河流湖泊湿地生成,与此同时原有河流湖泊湿地面积扩张,使得河流湖泊湿地整体性增强,这主要是缘于特大洪水提供的丰富水源使得河道附近的沼泽湿地,以及湖泡周边的盐碱地大量的演变为河湖湿地.(4)霍林河1998年特大历史洪水虽然对沼泽湿地亦具有一定的恢复功效,亦主要来源于河道附近的盐碱地的转换输入贡献,但效果不及河流湖泊湿地的显著,这可说明单次偶发的特大洪水可能较难起到彻底恢复退化洪泛湿地景观的功能,而要实现该目标,可能需要超标准洪水的频繁泛滥,这需要进一步的研究.(5)特大历史洪水在促进流域下游洪泛湿地景观扩张的同时,洪水的冲洗盐作用对流域的盐化环境亦具有很好的改善作用,因此亦可以通过增大洪水的泛滥来改善流域严峻的盐化环境.但是需要多大频次的、多大量级的洪水泛滥作用还需要更进一步的研究.(6)偶发的特大历史洪水虽然可以很好的实现河流湖泡湿地景观的恢复,但这种恢复的效果能持续多久,还需要进行更长时间序列的更新研究.     

近50年来霍林河流域下游沿岸土地利用变化过程

本文以干旱半干旱脆弱区霍林河流域下游沿岸为研究靶区,利用1954和1964年地形图,1986、1996和2000年的TM遥感影像作为基本信息源,在GIS支持下,建立土地利用空间数据库,通过分析不同时段各土地利用类型的动态变化及其转换过程,揭示近50年来霍林河流域下游沿岸土地利用变化过程及其规律。研究得出,耕地和草地是霍林河流域下游沿岸的主要土地利用类型,次之为盐碱地,湿地和林地比重较小,人居地和沙裸地最小。计算土地利用动态度进行土地利用变化的数量分析发现,各土地利用类型之间以及同一土地利用类型在不同的研究时段都呈现出显著差异的速度变化,表现在速度变化的绝对量上、速度变化的方向上和土地利用综合动态度上,耕地和草地始终相反的速度变化方向说明二者之间存在密切的相互转换关系,而人居地和盐碱地始终一致的速度变化方向则说明人类干扰活动是研究区盐碱地面积扩张变化的一个主要因素。土地利用转换分析显示,霍林河流域下游沿岸各土地利用类型稳定性排序为耕地>湿地>人居地>盐碱地>林地>草地>沙裸地,它们之间的转换变化具有显著的差异性,同一土地利用类型在转出和转入土地利用类型及其转换量上的表现不同,且随时间推移亦发生变化,且这种转换变化在区域分布及空间构型上存在差异。转出的减少作用和转入的增加作用相叠加决定着研究区不同时段各土地利用类型的动态变化。     

中国天山西部匹里青河的洪水及其成因

匹里青河位于天山西部,地处西来水汽输送通道,流域山体高大、支沟发育、坡陡流急,山洪灾害频发,其主要洪水类型为混合型洪水和暴雨洪水。50多年实测洪水资料表明,随着系列的增加,该河年最大洪峰流量模比系数、变差系数、偏态系数均呈波动性增加趋势,说明其洪水发生频次及量级均有增大趋势。通过对该站同期气温、降水、泥沙分析,冬季流域...     

半干旱地区霍林河流域径流演变及其影响机制研究

霍林河流经内蒙古东部和吉林西部 ,处于生态环境脆弱带上 ,是半干旱气候条件下具有典型意义的内流河 ,其径流特征及演变规律对区域环境演化和水资源开发利用具有重要影响。本文通过对霍林河近半个世纪以来径流资料的分析 ,采用 Kendall趋势分析及关联度分析定量研究了径流演变的规律 ,分析了径流变化的驱动机制及对生态环境的影响。结果表明在气候干旱化和人类活动的双重影响下 ,霍林河径流演化具有阶段性、突变性和非线性的特点 ,流域水土资源的不合理开发是导致水文情势变化、水域功能消退的主要驱动力。探讨内流河径流演变的规律对区域生态环境的影响以及水资源合理开发利用具有积极现实的意义 ,为区域资源的合理开发和社会经济可持续发展提供科学依据     

新疆呼图壁河流域水文特征分析

呼图壁河是天山北麓中段第二大河流,根据该河多年统计资料,从流域气候、径流、泥沙、水质等方面对其水文特性进行分析。得出呼图壁河径流年际变化稳定、年内分配极不均匀;洪水特征为峰高、量大且持续时间长。洪水传播时间与传播速度与洪峰流量的量级、区间来水河段特征、洪水类型及洪水特性等因素有关;河流泥沙年际变化较大,年内分配极不均匀,与径流的年内变化基本一致;受人类活动的影响,河流水质沿程有恶化的趋势。     

新疆山区中小河流洪水预报模型及其应用

我国中小河流防洪标准普遍偏低,突发性洪水频繁,洪灾损失极为严重。选取新疆山区金沟河和奎屯河,通过MODIS遥感数据提取流域积雪覆盖率,并结合气象台站数据,基于SRM融雪径流模型、逐步多元回归模型和最近邻抽样模型,对流域进行径流模拟。结果显示:3种模型均能很好的模拟金沟河与奎屯河流域的径流过程,率定期与检验期Nash效率系数均达到0.7以上,且3种模型各有优缺点,说明融雪径流模型、逐步多元回归模型与最近邻抽样模型能够应用于金沟河与奎屯河流域的洪水预报,对新疆山区中小河流域防洪预警具有一定的指导意义。     

近50年来霍林河流域径流量演变规律研究

霍林河是松嫩平原西部地区科尔沁、向海和查干泡湿地的重要补给水源,选取流域内3个代表站的径流实测资料,对50年来流域年径流量、雨季径流量、枯季径流量和基流径流量的演变规律进行分析。径流量年均序列的db3小波函数多分辨率分析表明,期间流域径流量总体呈下降趋势;“距平累积法”将径流量序列分为3个阶段,1965年以前径流量偏多阶段,1965~1985年的偏少阶段和1985年以后的偏多阶段;1985年以后流域径流量较强的增长趋势变化用Mann-Kendall非参数检验法检测达到突变水平,增长突变发生在1985~1990年;Morlet小波分析表明,不同类型径流量主要存在3个尺度的周期变化,预测在未来几年流域将逐渐进入较大尺度的枯水期之下的较小尺度的相对丰水期。     

流域水空间规划与管理研究——以霍林河流域为例

水资源的更新再生和可持续性存在的能力,是靠水循环过程年复一年、周而复始补给的.维持水的可持续性,保障水循环过程的正常运转,是自然社会持续发展的一项重要任务.水循环过程中,水的类型和资源属性变化与地理地质要素空间组合及其相互作用密切相关,水资源的形成、存在、迁移和转化需要一定的空间介质和场所,以满足水量调蓄、赋存、补给、更新以及水质保护的空间需求.这些空间介质和场所在流域尺度上,是指河流和其支流及与之相连接的湖泊、湿地等各种水体、那些受洪水波及的洪泛平原和部分坡地,以及此范围内的地下含水层系统所共同占据的空间.流域发展过程中,人类往往关注自身社会经济发展需求,而忽略了水系统的空间要求,流域内土地利用程度和范围不断扩大,水流在流域下垫面土层中的垂向和侧向运行路径受阻,干扰了流域中各种径流成分的生成过程和流域下垫面对降水的再分配过程,流域空间上水调节能力降低,滞洪能力减弱,陆地承载水量越来越少,加剧了水资源的时空分布不均,流域水质恶化,生物多样性降低,严重威胁着水资源安全.基于此,在流域水空间概念的基础上,提出流域水空间规划原则和规划程序,并以霍林河流域为例,建议对干旱和半干旱区流域采用水空间规划和管理措施,试图通过规范流域水空间管理,实现流域水和土的联合管理.     

新疆哈密石城子河流域水文水资源分析

不同地区的自然地理环境塑造了不同特征的河流,同时,河流的活动也在不断改变着与自身有关的自然环境。我国暖温带干旱区除塔里木河流域的水文特征、水资源及其合理利用有较多的研究外,其余中小河流的研究甚少。哈密石城子河的水文特征基本反映了我国暖温带干旱区众多中小河流域的水文特征。利用石城子河流域水文气象站1956-2001年资料,对该流域径流形成、洪水、泥沙、水质等进行分析,以揭示我国暖温带干旱区中小河流域的基本特征,为科学利用该地带中小河流域水资源提供理论依据。     

新疆额尔齐斯河流域“2005•6•1”大洪水分析

2005年6月1-2日,额尔齐斯河全流域发生了突发性融雪和降雨混合型大洪水,各支流洪水峰高、量大、来势凶猛,其中额尔齐斯河源头支流--库依尔特斯河发生有实测资料（50 a）以来最大洪水,布尔津河、哈巴河发生有实测资料（54 a）以来第2、第3位洪水,给当地造成较大经济损失。根据河流实测洪水、降水量、气温、高空和环流形势等资料,对这次洪水的成因、过程、特点进行分析。结果表明：① 在额尔齐斯河流域融雪与降雨混合型大洪水的形成过程中,前期气温和大尺度降水天气起重要作用;② 从[JP2]有实测洪水记录的50多年以来,第4次发生全流域性洪水,在全球气候变暖和随阿勒泰地区冬季降水量明显增多的形势下,灾害性洪水出现的可能性将增加;③ 由于融雪与降雨混合型洪水过程较长、峰量较大,因此,洪水挟沙能力较强,在设计蓄水工程时要引起重视;④ 对下游有较大城市或重点水利工程的山区河流,要加强防洪预警系统的建设力度,以减轻灾害性洪水造成的损失。     

Response to flooding intensity in Elytrigia repens, E. intermedia (Poaceae: Triticeae) and their hybrid

Response to flooding intensity in three closely related taxa, Elytrigia repens, E. intermedia and their hybrid was studied. Plants were exposed to three intensities of flooding for a 30‐day period. Response to flooding intensity was estimated by measuring dry mass of the following: total biomass, above‐ground living biomass, above‐ground dead biomass, below‐ground biomass, rhizome and root mass and by the allocation of dry mass into rhizomes and root:shoot ratio. Reduction of nearly all the biomass compartments with increasing flooding intensity was observed in the three taxa. All three taxa can thus be regarded as flood‐intolerant. Based on the parameters measured, E. repens is regarded as the relatively most flooding‐tolerant, E. intermedia as the least tolerant, while the hybrid displayed intermediate flooding tolerance. The higher flooding tolerance in E. repens was likely related to its ability to accumulate a sufficient mass of rhizomes before flooding, due to higher regeneration ability. E. repens also displayed the highest phenotypic plasticity, as deduced from the reaction norms constructed for total biomass and rhizome mass of particular clones of the three taxa studied. This indicates that, on the species level, E. repens is better adapted to changing environmental conditions and it can be expected to colonize flooded soils. Both Elytrigia species also occur as weeds: E. intermedia grows in agricultural environments in warm regions, while E. repens infests many different types of habitats. Where they co‐occur, hybridization between them may lead to the enrichment of their gene pools with genes responsible for survival of the parental species under extreme conditions; their weedy potential may thus be enhanced.     

水旱两种栽培模式下海南山栏稻对白叶枯病抗性鉴定与评价

为研究山栏稻对白叶枯病抗性,本试验以17个山栏稻品种为材料,在大田与温室大棚中同时种植,于大田中观察山栏稻在水、旱两种栽培模式下对海口当地白叶枯病菌的自然抗性并测产;在温室中检测水、旱两种栽培模式下山栏稻对菲律宾白叶枯病菌小种PXO99(P6)、PX145(P7)的抗性;并以基因功能性标记检测其抗性基因,分析各指标与抗病性的关系。结果表明,大田环境下17个供试品种中有12个品种在水作栽培模式下感病指数高于旱作,有10个品种水作栽培模式下产量比旱作高。温室中用P6接种山栏稻,水作模式下仅有1个品种表现抗病,8个品种感病;旱作模式下2个品种表现抗病,3个品种感病。接种P7,水作时表现抗病和感病的品种数量分别为7个和2个;旱作时表现抗病的品种高达9个,仅1个品种感病。供试品种中有16个品种含有Xa1抗病基因,4个品种含有Xa27抗病基因,所有品种均不含xa13、Xa21抗病基因。因此认为,山栏稻对海口当地白叶枯病菌小种以及菲律宾白叶枯病菌小种都有一定抗性,且抗性受栽培条件的影响,山栏稻旱作时抗性强于水作。     

Direct and indirect impacts of different water regimes on the invasive plant,alligator weed (Alternanthera philoxeroides), and its biological control agent,Agasicles hygrophila

Invasive weeds are broadly affected by natural disturbances, such as flooding and drought. While these disturbances can directly affect the outcome of a plant invasion, they can also indirectly affect the population dynamics of the invasive plant's natural enemies. However, how flooding and drought alter the interactions of invasive plants with their natural enemies and what impact these events have on the invasive plants have been little studied. This study reports on the effects of flooding and drought on the invasive plant, Alternanthera philoxeroides, its biological control agent, Agasicles hygrophila, as well as their interactions in field and laboratory experiments. It was found that drought decreased the stem length and number of internodes of A. philoxeroides, while flooding reduced the number of branches, relative to those in the control treatments. Both drought and flooding significantly decreased the total number of ramets, as well as the root and shoot mass of this weed, compared to a less drastic water regime. Drought indirectly suppressed the population growth of Ag. hygrophila by decreasing plant palatability. Indeed, herbivory by Ag. hygrophila had little impact on A. philoxeroides under drought conditions. The results of this study suggest that drought can reduce the biological control of A. philoxeroides indirectly by interrupting plant–insect interaction. Therefore, understanding how invasive plants and enemies interactively respond to seasonal climatic disturbances will provide important information for improving and predicting the management efficiency of invasive weeds.     

The effects of sowing depth and flooding on the emergence, survival, and growth of Fimbristylis miliacea (L.) Vahl

Glasshouse experiments were conducted from March to July 2003 to determine the effects of sowing depth, and the time, duration, and depth of flooding on the emergence, survival, and growth of Fimbristylis miliacea (L.) Vahl. The treatments that were evaluated in the first experiment were three seeding depths (0, 0.5, and 1.0 cm), while in the second experiment, three flooding depths (saturated soil with no standing water and soil with water depths of 5 and 10 cm) and three flooding durations (7, 14, and 21 days from sowing) were evaluated. In the third experiment, three flooding depths (saturated soil with no standing water, and soil with water depths of 5 and 10 cm) and four flooding regimes (7, 14, 21 or 28 days after sowing [DAS]) were evaluated. Surface seeding gave the highest emergence rate compared to the 0.5 cm and 1.0 cm soil depths. A significantly higher emergence rate was recorded with the saturated conditions than with the flooded conditions. A flooding duration of ≥ 14 days showed a clear trend of reduced emergence with increasing flooding depth. A significantly higher survival rate, plant height, root length, number of leaves, and dry matter were recorded at soil saturation followed by the 5 cm and 10 cm flooding depths when flooding was simulated at 7 and 14 DAS. When the flooding was delayed to 21 and 28 DAS, the 10 cm flooding depth was required to suppress this weed. The results provide sufficient evidence to confirm that from deeper seed burial (1 cm sowing depth), flooding depths of ≥ 5 cm of durations of 14 and 21 days and at the onset of flooding within 14 DAS were effective in suppressing the emergence and growth of F. miliacea .     

塔里木河下游典型地区地下水位和植被对生态输水的积极响应

由于近50年来人类不合理的水土资源和生物资源的开发利用,导致塔里木河下游大西海子水库以下363km河道断流近30年,地下水位大幅度下降,由地下水维系的植被群落出现严重退化,塔里木河下游绿色走廊生态恶化趋势严重。为此,新疆维吾尔自治区人民政府于2000年4月实施了旨在挽救当地生态环境的塔里木河下游应急生态输水工程,从2000年5月开始至2006年9月,由塔里木河流域管理局与巴州、农二师共同组织8次向塔里木河下游生态应急输水。输水后地下水位大幅升高,相应地,塔里木河下游绿色走廊的生态与环境发生了一系列动态变化。本文根据实测数据和前人研究的资料分析基础上,对塔里木河下游典型地区地下水位和植被对生态输水的积极响应进行探讨。     

近200年来关中地区洪涝灾害研究

本文通过对历史文献资料的统计与分析,以关中地区1801-2005年的洪涝灾害等资料为依据,基于MATLAB分析了这一时期该地区洪涝灾害的时间变化特征、空间变化趋势,并应用了在最小二乘法意义下7次多项式的拟合预测了该地区未来五年(2006-2010年)洪涝灾害发展趋势。结果表明,该地区近200年以来,共发生洪涝灾害83次,平均每2.47年一遇,其中1850-1930年洪涝灾害发生频率明显增加,三十年代遭遇最为频繁,从这以后又逐渐减少;二十世纪三十年代洪涝灾害发生频率有明显增加的趋势,尤其在六十年代发生频率达到最高。关中地区的五个省辖区中,从整个这一时期来看渭南地区遭受洪涝灾害最为频繁,铜川受灾较轻,其他三个地区居于中间;洪涝灾害的阶段性、地区分布的不均匀性,与该地区的自然条件、所处的气候背景以及人类活动有关。预测了在未来的5年(2006-2010年)内,将发生0.9653次洪涝灾害。     

Genes related to flooding tolerance during germination and early growth of weedy rice

Evolution of flooding tolerance in weedy rice has occurred in several rice-growing regions, but the genes related to this process and the environmental effects are unknown. The objective of this study was to analyse the expression of genes related to flooding tolerance in response to temperature and flooding during the initial establishment of weedy rice. The experiments were carried out with rice cultivars IRGA 417 and Nipponbare, which are sensitive to flooding, and weedy rice ITJ03 and AV04 genotypes that have high and intermediate tolerance to flooding, respectively. The expression of genes related to reserve mobilisation, anaerobic respiration, escape and quiescence strategies was analysed at periods up to 24 days after sowing. The flooding tolerance of weedy rice genotype ITJ03 was associated with the expression of RAmy3D and OsTPP7 , which are involved in the mobilisation of carbohydrate reserves, ADH1 and ADH2, which participate in anaerobic respiration, and SNRKL1 that triggers rapid elongation of the coleoptile and emergence. Although the genes PDC1, SUS3 and SUB1 are important for flooding tolerance in cultivated rice, their expression was not directly related to flooding tolerance in weedy rice. A temperature of 20°C reduced levels of expression of the RAmy3D, ADH2 and SNRKL1 genes and low temperature had a negative effect on the establishment of weedy rice. Breeding of rice genotypes with tolerance of low temperatures and anaerobic conditions may be a viable strategy to improve the control of weedy rice in paddy fields.     

The more we do,the less we gain? Balancing effort and efficacy in managing the Solidago gigantea invasion

Developing invasive plant management strategies is an important task in modern ecology, conservation biology and land management. Solidago gigantea is considered a problematic invader in Europe and Asia, where it forms dominant stands that can decrease species diversity. There is, therefore, an urgent need for effective management to reduce S. gigantea infestations and their negative impacts. We examined the efficacy of multiple approaches to S. gigantea management in Hungary. In our study, we evaluated the effect of several long-term management techniques such as grazing, mowing and periodic flooding on the invader's density as well as native community diversity. In addition, we investigated the short- and long-term effects of mowing combined with other treatment options, to estimate the influence of increased management intensity. Our results indicate that all tested management techniques had negative impacts on S. gigantea density. Short-term mowing did not appear to improve species diversity in the resident community; however, all long-term options improved species diversity. Moreover, combining treatments with mowing varied in its effectiveness; mowing once increased the efficacy of flooding, but decreased the efficacy of grazing, while mowing twice decreased efficacy of flooding. We suspect this is due to the increased intensity of disturbance, which does not allow for the natural recovery of communities, and after management ceases, invasion is able to re-occur. Our results indicate that for effective management, we need to combine management options which act via different mechanisms, leading to cumulative positive effects on the resident community when applied at moderate levels.     

宁夏引黄灌区春小麦畦灌试验研究

通过田间畦灌试验,分析春小麦不同生育阶段的需水量及水分盈亏量,评价不同畦灌处理下的灌水质量及节水增收效果。结果表明:畦灌小区50m×2m与漫灌(CK)相比较,水分利用效率提高了26.78%,产量增加了13.08%,具有一定的节水增效作用,结合各地实际生产情况合理推广利用能够取得良好的经济效益。     

Effect of flooding on the survival of Leptosphaeria spp. in canola stubble

This study used a versatile temperature‐control device to assess the effect of temperature (12–40°C) and duration (2–12 weeks) of flooding on the survival of Leptosphaeria spp. in canola (Brassica napus) stubble. Canola basal stems with blackleg symptoms were submerged in water in small glass jars containing 20 cm³ soil on a thermogradient plate capable of simultaneously maintaining up to 96 independent temperature regimes. Flooded stems were sampled at 2‐week intervals, surface‐sterilized, and incubated on V8‐juice agar for 10 days to recover the pathogen. Flooding for 2 weeks substantially reduced pathogen recovery relative to non‐flooded controls and the pathogen was not recovered after 6 weeks of flooding, irrespective of temperature. The pathogen was eliminated slightly more rapidly at flooding temperatures >20°C than at 12–16°C. There was no difference between Leptosphaeria maculans and L. biglobosa in their ability to survive flooding. Stem tissues degraded most rapidly during the first 2 weeks of flooding, corresponding to a quick decline in pathogen survival during the same period. These results indicate that a paddy rice crop following winter rapeseed may minimize the impact of blackleg by eradicating the inoculum of Leptosphaeria spp. in stubble.