扎龙湿地补水 鹤类数量增加

位于黑龙江省齐齐哈尔市东南的扎龙自然保护区,面积21万公顷,被誉为丹顶鹤的故乡。由于20世纪90年代中后期的连年干旱,扎龙湿地明水面积一再萎缩,严重威胁当地鹤类的栖息生存。为了抢救扎龙湿地,黑龙江省首开国内湿地补水的先河,连续4年对扎龙湿地累计“注水8.18亿立方米,不仅使扎龙湿地初步恢复生机,而且对松嫩平原黑土地的保护、大庆地下水下降漏斗的治理,都将产生积极的影响,“补水工程收到成效。补水后,目前扎龙湿地明水面积已经超出核心区400平方公里,鹤类数量增加到400多只,达到历史最好水平。扎龙湿地的大面积明水,还将对大庆地区的…     

嫩江源湿地的生态保护价值的探讨

嫩江源湿地是松花江的主支流,担负着下游工农业生产和人民的生活,也是大庆地下补水和扎龙湿地补水的来源,本身就具有多种生态服务功能,是极具保护价值的湿地.     

扎龙自然保护区春季水禽的调查

水禽是扎龙保护区的主要保护对象和湿地生态系统的重要组成部分。为了监测扎龙保护区鸟类的动态变化,2011年3—5月,我们对湿地内迁徙水禽和繁殖水禽的数量和种类等做了系统的调查。调查结果显示:2011年扎龙湿地春季迁徙水禽35种,繁殖水禽46种;迁徙时间从3月中旬持续到5月上旬;扎龙湿地实施补水后,繁殖鹤类的数量较补水前显著增多;与以往的监测数据比较,黑翅长脚鹬等鹬类和白翅浮鸥、须浮鸥等鸥类的数量有逐年增加的趋势,黑水鸡、骨顶鸡以及苍鹭、草鹭等水禽的数量趋于减少。     

生态补水在扎龙湿地自然恢复中的作用

扎龙湿地退化主要原因是湿地缺水,通过生态补水,促进湿地水体、湿地植被、湿地土壤及其鹤类等主要水鸟的恢复,从而使湿地恢复到一个比较高的水平,使其发挥正常的生态功能.     

中国湿地生态补水发展现状及其生态效应研究进展

湿地水资源状况直接决定了湿地生态系统的结构和功能,生态补水已经成为解决缺水地区湿地萎缩和退化、生态环境问题的重要措施之一。文中介绍了中国湿地生态补水的发展现状、实践探索和保障机制,综述湿地生态需水和生态补水策略研究,以及补水对区域水资源、湿地景观和植被、湿地生物群落和生态系统服务等影响的研究进展;总结当前中国湿地生态补水的发展成就及生态补水实践探索,分析相关研究中存在的问题;并从区域规划、方案编制、实践探索、生态系统影响评估等方面给出了未来湿地生态补水发展和研究的建议,以期为中国湿地生态补水研究及实践提供借鉴。     

扎龙湿地的水环境特征及其对珍稀水禽的影响

通过野外调查和室内分析,探讨了近年扎龙湿地的水环境系统的特征及对珍稀水禽的影响。结果表明:扎龙湿地是整个嫩江流域生态环境脆弱区,表现出整体退化的趋势。水质富营养化严重:各项指标(除CODMn外)的含量最高的时期都为Ⅴ级,远远大于国家对湿地水质Ⅱ级的规定。扎龙湿地水质特征存在年内变化和空间上的差异性。农业活动较频繁地区扎龙湖的水质污染最重。扎龙湿地水体中重金属各项指标都低于Ⅰ类水质标准,扎龙湿地底泥中Cu、Pb、Zn、Cd、Hg超过其背景值。常见水禽的食物———鱼体内重金属含量的平均值分别是水体中含量的数百倍。珍稀水禽体内也都不同程度地富集了一定的重金属含量。湿地的退化和重金属的富集应该引起相关部门的重视。     

扎龙湿地芦苇对火烧的生态响应

扎龙湿地是珍稀水禽的重要栖息,具有涵养水源、调节气候、降低风速等生态效应。文章探讨了扎龙湿地植被类型、湿地火烧的产生及扎龙湿地芦苇对火烧产生的生态响应。调查和资料表明：在干旱缺水的湿地地表火烧对季节性积水或常年不积水地段芦苇影响严重,芦苇退化明显。火烧促使湿地植被演替发生变化。     

扎龙湿地芦苇恢复与生态补水分析

芦苇是珍稀水禽的栖息地，具有调节气候、涵养水源、降低风速等生态效应。文章介绍了扎龙湿地植被的类型、影响芦苇生长的主要因子。资料表明，严重缺水使芦苇退化，生物量显著降低，而水量过多又造成芦苇生长受限，只有适量的生态补水才能促进芦苇的生长。     

扎龙湿地移民区湿地恢复与保护对策

作为国际重要湿地之一的扎龙湿地,近些年来由于受到人为因素的干扰,湿地植被与湿地野生动物受到严重影响,为此,国家林业局启动了扎龙湿地生态移民计划.文章针对扎龙湿地生态移民的意义以及移民区湿地恢复与重建原则、措施方法等问题进行了详细论述,提出了扎龙移民区湿地生产活动的管理方法与措施,为扎龙湿地生态移民区的湿地恢复与保护提供...     

扎龙湿地植物多样性现状及恢复与保护对策

通过对国际重要湿地——扎龙湿地植物多样性的分析,详细论述了植物多样性退化原因,并提出了植物退化的恢复与保护对策,为扎龙湿地的恢复与保护提供依据。     

地表水水生生物指标与水质理化指标相关性研究

本文应用逐步回归分析方法，对岷江水系1993--1999年地表水的水生生物与水质理化同步监测数据进行相关性分析，结果表明，水生生物监测指标与水质理化监测指标之间存在明显的相关性。其中，紫露草平均微核率主要与水质指标中的COD、pH值两个指标相关，不同于污染水体；大型蚤24h死亡率主要与水质指标中的酚、Cr^6 、As^2 |三个指标相关。获得的回归方程具有较好的预测效果。     

香蒲对衡水湖某些水质指标变化特征的影响

对衡水湖香蒲大量繁殖水域和无香蒲深水水域的水温、pH、DO、COD进行了分析比较。结果表明:香蒲在气温较低时期,有明显提高水温作用。近几年香蒲过度繁殖,其植株死亡后大量残体沉积在湖底,导致香蒲区在高温时期pH、DO明显下降,COD明显上升。     

Assessing water use and soil water balance of planted native tree species under strong water limitations in Northern Chile

Some forest plantations with native species are established in semiarid central Chile to compensate for industrial activities such as those of mining. Two of those operational forest plantations were monitored from age 1 to 3 years-old (2014–2016). Some plant attributes and soil volumetric water content (VWC) were monitored for eight native tree species (Acacia caven, Schinus polygamus, Porlieria chilensis, Lithraea caustica, Quillaja saponaria, Cryptocarya alba, Drimys winteri and Maytenus boaria), and a water balance model fitted to assess plant water use. Site preparation comprised planting holes of 40 cm?×?40 cm by 50 cm in depth dug with a backhoe. Substrate was removed and mixed with compost in proportion 70:30 before mixing it in the planting hole. Planting holes acted as water reservoirs over the study period with soil VWC generally increasing with soil depth being also less variable deeper than in the upper soil layers. The ratio of adaxial (upper leaf side) to abaxial (lower leaf side) stomatal conductance approximately followed a species gradient from xeric to mesic. Irrigation represented about 26% and 53% of the total water input for the sclerophyll and the D. winteri plantation, respectively. At the plant level (0.4?×?0.4 m), soil evaporation and transpiration of D. winteri (273 and 232 mm year^?1, equivalent to 43.7 and 37.1 L plant^?1, respectively) were about twofold the values for the sclerophyllous/malacophyllous plantation (138 and 128 mm year^?1, 22.1 and 20.5 L plant^?1, respectively). We suggest the water budget for the sclerophyll/malacophyllous plantation was tight but feasible to be adjusted while for D. winteri irrigation was excessive, could be drastically reduced, and suppressed altogether if planted in gullies. We believe water balance models and soil moisture content sensors could be used to better plan and manage irrigation frequency and amounts in compensation forest plantations in semiarid central Chile.     

Diffusion of bound water in wood

Summary Fick's law states that during steady-state diffusion, moisture flux is proportional to the gradient in moisture concentration, making concentration gradient the driving force for diffusion. Although Fick's law permits convenient comparisons between predicted and measured moisture contents, fundamental and experimental difficulties with it have been reported. In this paper, the dependence of spreading pressure on vapor pressure and temperature is developed. This information is used to show that gradients in spreading pressure and chemical potential are not proportional. Spreading pressure gradient is considered the correct driving force because the associated transport law can be derived from first principles.The author wishes to thank Dr. Christen Skaar for his interest and advice during preparation of this paper for publication     

井点降水在深水承台施工中的应用

文章结合哈尔滨松花江公路大桥8#主墩台基坑井点降水施工的过程，阐述了井点降水在深水承台施工中应用的要点及其优越性。     

Diffusion of bound water in wood

Summary Choong's (1963) data for isothermal sorption of water vapor by wood are used to compute pressures, chemical potentials, and entropies of water in the wood specimens of his nonisothermal mass equilibrium experiments. Entropies of both the bound water and water vapor were reasonably constant. A balance existed between thermal diffusion and mass diffusion, as indicated by gradients in temperature and chemical potential. This balance also is suggested by opposing gradients in spreading pressure and vapor pressure. Equal chemical potentials showed that the vapor and bound water were in equilibrium. The model proposed by Siau (1980) for nonisothermal diffusion is consistent with these results. Expressions are given for the two unknown parameters in this model: moisture conductivity and heat of transfer. The constant entropy of water vapor is used to show that the heat of transfer exceeds the activation energy for bound water diffusion by about 25 percent.The author wishes to thank Dr. Christen Skaar for his helpful comments during preparation of this paper for publication     

Diffusion of bound water in wood

Summary A model for isothermal bound water diffusion in wood is derived from Babbitt's (1950) analysis of diffusion in adsorbing solids. Calculations of the energy required for water molecules to become dissociated from their sites is identified as one component of the activation energy for diffusion. Consideration of the resistance to diffusion leads to a second component of activation energy associated with overcoming the attraction of water molecules for themselves. Also, an approximate expression for the resistance coefficient is developed. These results are combined into a transport model for bound water. The model shows that equations for bound water movement based on fluid mechanics (Babbitt 1950) and thermodynamics (Katchalsky, Curran 1965) are identical when the driving force for diffusion is defined as the moisture flux per unit transport coefficient. Activation energies and diffusion coefficients derived from the model compare favorably with literature values.The author wishes to thank Dr. Christen Skaar for his interest and advice during preparation of this paper for publication     

Growth, leaf morphology, water use and tissue water relations of Eucalyptus globulus clones in response to water deficit

Changes in leaf size, specific leaf area (SLA), transpiration and tissue water relations were studied in leaves of rooted cuttings of selected clones of Eucalyptus globulus Labill. subjected to well-watered or drought conditions in a greenhouse. Significant differences between clones were found in leaf expansion and transpiration. There was a significant clone x treatment interaction on SLA. Water stress significantly reduced osmotic potential at the turgor loss point (Pi0) and at full turgor (Pi100), and significantly increased relative water content at the turgor loss point and maximum bulk elastic modulus. Differences in tissue water relations between clones were significant only in the mild drought treatment. Among clones in the drought treatments, the highest leaf expansion and the highest increase in transpiration during the experiment were measured in those clones that showed an early and large decrease in Pi0 and Pi100.     

Leaf water relations of Eucalyptus cloeziana and Eucalyptus argophloia in response to water deficit

Leaf water relations responses to limited water supply were determined in 7-month-old plants of a dry inland provenance of Eucalyptus argophloia Blakely and in a humid coastal provenance (Gympie) and a dry inland provenance (Hungry Hills) of Eucalyptus cloeziana F. Muell. Each provenance of E. cloeziana exhibited a lower relative water content at the turgor loss point, a lower apoplastic water content, a smaller ratio of dry mass to turgid mass and a lower bulk modulus of elasticity than the single provenance of E. argophloia. Osmotic potential at full turgor and water potential at the turgor loss point were significantly lower in E. argophloia and the inland provenance of E. cloeziana than in the coastal provenance of E. cloeziana. There was limited osmotic adjustment in response to soil drying in E. cloeziana, but not in E. argophloia. Between-species differences in water relations parameters were larger than those between the E. cloeziana provenances. Both E. cloeziana provenances maintained turgor under moderate water stress through a combination of osmotic and elastic adjustments. Eucalyptus argophloia had more rigid cell walls and reached lower water potentials with less reduction in relative water content than either of the E. cloeziana provenances, thereby enabling it to extract water from dryer soils.     

The effect of openings on combined bound water and water vapor diffusion in wood

This study was undertaken to estimate the effect of openings between cell walls on combined bound water and water vapor diffusion in wood. Using a newly developed model, the radial and tangential moisture diffusion coefficients can be predicted depending on the opening area. The new model explicitly involves a term for water vapor diffusion through the openings, as well as a term for the combined diffusion of bound water and water vapor. A classical model developed by Stamm and Choong had higher longitudinal moisture diffusion coefficients than that in the parallel model at higher moisture content, which is inconsistent with the Wiener bound rule. The new model suggested in this article is useful for analyzing the experimental results and understanding the variability of the diffusion coefficients.