中国历史时期干旱区湿地及其人─地系统动力学的初步研究

本文用历史观点，初步探讨了我国干旱区湿地与人─地系统动力学机制。研究表明，虽然干旱区气候及其干暖化发展与湿地发生学相悖，但也不乏湿地分布．干旱区湿地一直处在衰退过程之中，其原因总的来说是区域性人—地系统动力学负效应综合作用的结果。     

Determination of water requirements of the Gavkhuni wetland,Iran: A hydrological approach

This study compared three hydrological methods – low flow frequency analysis, flow duration curve (FDC), and concentration-discharge (C-D) modeling – to determine the water requirement of the Gavkhuni wetland located in an arid region of Iran. Due to the effects of water impounding upstream on the hydrological regime of the Gavkhuni's inflow after construction of the Zayandehrud dam, none of the methods produced satisfactory results.Consequent modification of the hydrological regime of the wetland's inflow using a scaling process allowed all the methods except low flow frequency analysis to dependably estimate the base flow for the wetland. The results of the C–D method revealed that this method can provide a minimum health condition from the water quality point of view, while the results of the FDC demonstrated that not only the inflow estimated using this method can supply minimum conditions in terms of water quality parameters, but it also covers most areas of the wetland, based on the results of hydraulic modeling.The results reveal that the hydrological methods implemented in this study can dependably estimate environmental water allocation for wetlands in arid and semi-arid regions when there is no detailed knowledge about the biological requirements of the wetlands' biota.     

Incorporating the human-Aedes mosquito interactions into measuring the spatial risk of urban dengue fever

To block human–mosquito interactions by eliminating dengue vectors, Aedes aegypti L. and Aedes albopictus Skuse have been considered the main strategies for dengue prevention. Spatial targeting of dengue risk areas is the highest priority for implementing control measures. However, the frequency of human-Aedes mosquito contacts as human factors for assessing the risk of dengue has not been taken into account by past studies. The objective of this study is to clarify the geographic effects of crowd-gathering places on the frequency of dengue vector for assessing the spatial risk of exposure to dengue in Kaohsiung City, Taiwan. A geographic information system (GIS) was used to integrate crowd-gathering places and ovitrap locations for investigating potential human–mosquito contacts. A negative binominal regression was used to estimate the spatial risk of dengue by integrating vector mosquitoes from the ovitrap survey, urban environmental risk factors and human crowd-gathering places as the surrogate of human activities. We also compared the estimated spatial risk of exposure to dengue with traditional approaches. Our results indicated that the spatial distribution of the residential populations is not consistent with the locations of social activities. Additionally, people closer to crowd-gathering places have a higher frequency of contact with Ae. aegypti than with Ae. albopictus larvae. The dengue risk is caused by the human-Aedes aegypti contacts concentrated around city centers, while the risk caused by the human-Aedes albopictus contacts is distributed around the city boundary. Our study concluded that only relying on infected human cases or the abundance of vector mosquitoes is not enough for assessing the spatial risk of dengue. This reliance could ignore the areas with frequent vector existence and; therefore, result in the underestimated risk of dengue transmission. This study demonstrates the methodological framework for estimating the potential dengue risk and identifies the crowd-gathering places that facilitate dengue transmission.     

黄河流域湿地格局特征、控制因素与保护

准确掌握流域湿地资源的数量和分布, 是流域湿地评价、修复与保护决策的前提。利用“北京一号”小卫星数据对黄河流域2006年湿地格局现状进行了监测, 在GIS技术支持下对流域湿地资源分布的影响控制因素进行了分析, 进而结合不同流域分区水资源条件, 对流域湿地保护策略进行了探讨。研究表明, 2006年黄河流域湿地总面积为25134km²,其中, 河流、湖泊、沼泽、滨海、人工湿地面积分别占该流域湿地总面积的36.2%、8.0%、45.0%、3.9%、6.9%.受气候及水资源支撑条件的影响, 黄河流域重要湿地集中分布在源区高寒沼泽湿地、上游河湖湿地、中下游河道湿地以及河口三角洲湿地。流域天然湿地分布受气候影响显着, 随着气候干燥度的增加, 湿地率呈明显递减趋势。研究认为, 黄河流域大部分地区属于半干旱区, 水资源条件先天不足, 必须充分考虑流域和区域水资源的支撑能力和干扰影响, 在流域层面和河流生态系统的尺度上统筹考虑, 构建科学合理的流域湿地保护框架体系。     

Effects of Elevated Atmospheric CO(2) on Rhizosphere Soil Microbial Communities in a Mojave Desert Ecosystem

The effects of elevated atmospheric carbon dioxide [CO₂] on microbial communities in arid rhizosphere soils beneath Larrea tridentata were examined. Roots of Larrea were harvested from plots fumigated with elevated or ambient levels of [CO₂] using Free-Air CO₂ Enrichment (FACE) technology. Twelve bacterial and fungal rRNA gene libraries were constructed, sequenced and categorized into operational taxonomical units (OTUs). There was a significant decrease in OTUs within the Firmicutes (bacteria) in elevated [CO₂], and increase in Basiomycota (fungi) in rhizosphere soils of plots exposed to ambient [CO₂]. Phylogenetic analyses indicated that OTUs belonged to a wide range of bacterial and fungal taxa. To further study changes in bacterial communities, Quantitative Polymerase Chain Reaction (QPCR) was used to quantify populations of bacteria in rhizosphere soil. The concentration of total bacteria 16S rDNA was similar in conditions of enriched and ambient [CO₂]. However, QPCR of Gram-positive microorganisms showed a 43% decrease in the population in elevated [CO₂]. The decrease in representation of Gram positives and the similar values for total bacterial DNA suggest that the representation of other bacterial taxa was promoted by elevated [CO₂]. These results indicate that elevated [CO₂] changes structure and representation of microorganisms associated with roots of desert plants.     

新疆湿地资源时空变异研究

新疆地区是中国西北最干旱的地区,湿地分布最少的区域之一。新疆湿地资源以天然湿地为主．按湿地特征分为南疆和北疆两大区,由于南疆和北疆所处的地理位置不同,水文条件的差异．人类活动的影响程度不同．其湿地在空间分布结构、资源类型等方面表现出不同变化特点。本文利用遥感和地理信息系统技术方法对新疆湿地类型、资源现状进行研究,再利用GIS的空间分析功能,对新疆湿地资源动态变化及时空分布特征进行分析研究。     

Evaluation ofCitrullus colocynthis, a desert plant native in Israel, as a potential source of edible oil

Citrulus colocynthis(wild gourd) is a desert plant of the Cucurbitaceae, naturally adapted to arid environments. It was known in biblical times as a source of seed oil and its fruits were used as an efficient laxative. Accessions were collected in Israel and evaluated as a potential oil seed crop adapted to arid zones. It was found that its oil composition is similar to safflower oil, with a total of 80-85% unsaturated fatty acids. A potential yield of oil of 250-400 l ha⁻¹was calculated. The best yield was obtained during the first 4 weeks of the 10-week maturation period. Yield potential should be estimated under desert conditions in order to evaluate the plant's economic future as a crop suitable for an arid environment.     

Mosquito Habitat and Dengue Risk Potential in Hawaii: A Conceptual Framework and GIS Application*

Dengue is an emerging disease, and the distribution of the mosquito vector is partially mediated by environmental conditions. In this article, a new conceptual model is suggested that emphasizes the importance of including environmental variability in mosquito modeling studies. In an applied sense, mosquito habitat maps are developed for Hawaii using a GIS overlay of mosquito survival thresholds of temperature, precipitation, and stream/wetland location. Populated areas represent locations with the potential for an outbreak. The maps are adjustable based on expert knowledge input, and efforts to prevent or control outbreaks can be concentrated in those zones delineated by this study.     

干旱区水资源对城市化约束强度的综合评价模型

Water has become a key restricting factor of the urbanization process in developing arid areas. Based on qualitative and quantitative methods, we constructed an integrated indicator system to assess the status of water resources and urbanization system in arid area, and established an AHP model reformed by entropy technology to evaluate the temporal and spatial variations of water resources constraint intensity on urbanization. This model is applied to the Hexi Corridor, a typical arid area in NW China. Results show that, water resources constraint intensity on urbanization in the Hexi Corridor is bigger in the east and smaller in the west. It has changed from the less strong constraint type into the strong constraint type from 1985 to 2005, yet it decreased appreciably in recent years. At present, most areas in the Hexi Corridor belong to the less strong or strong constraint type. Through rational adjustment of water resources and urbanization system, the Hexi Corridor can still promote water resources sustainable utilization and accelerate the urbanization process. This study suggests that the integrated assessment model of water resources constraint intensity on urbanization is an effective method to analyze the conflicts between water resources and urbanization system in arid area. Foundation: Knowledge Innovation Project of the Chinese Academy of Sciences, No.KZCX2-YW-307-02; China Postdoctoral Science Foundation; K. C. Wong Education Foundation, Hong Kong Author: Bao Chao (1978–), Ph.D, specialized in urbanization and water sustainable utilization.     

Historical Land-Use/Land-Cover Changes in a Bottomland Hardwood Forest,Bayou Fountain,Louisiana

Historical surveys have proven important for assessing changes in forest composition and for providing insights into the influences of human activities on forest ecosystems. We used GIS to compare past land-use/land-cover information from General Land Office (GLO) surveys taken in 1849/1851 with current forest composition to illustrate the extensive changes that have occurred in bottomland hardwood forest composition over the past 150 years in East Baton Rouge Parish (EBRP), Louisiana. Agricultural lands, hardwood wetlands, and urban lands increased in area at the expense of rangelands and swamplands. A comparison of forest composition between A.D. 1849/1851 and today illustrates that the bottomlands were once a cypress-tupelo gum association but are now an elm-ash-sugarberry association. These changes are related to expanding urban conditions and encroaching human activities (e.g., levee construction) that substantially changed surface hydrological properties, especially the potential for flooding. Bottomland hardwood forests provide important services to low-lying urban areas mainly through storage of flood waters. Without conservation efforts, bottomland hardwood forests will experience continued human-mediated changes.     

Rainfall distribution around shrubs: Eco-geomorphic implications for arid hillslopes

A single shrub in a widely spaced shrubby area acts as a roughness element and, therefore, it can affect the distribution of the rainfall received on the ground surface surrounding it. This paper focuses on such rainfall distribution on arid hillslopes and its eco-geomorphic implications. Relatively simple methods were used to measure the rainfall around shrubs growing in a small basin that is associated with a prevailing wind direction during rain events. There was a trend toward significantly reduced rainfall onto bare soil areas located on the leeward side, compared with that on other bare soil areas along the hillslope. This may alert to another potential cause for patchiness in the hydrological response of arid hillslope systems.     

基于CIWLDI方法的苏州湿地景观健康评价

研制改进的基于空间最小景观单元的反距离权重景观开发强度法(CIWLDI方法 ),通过累积效应整合不同的土地利用分类,从能值的角度反映湿地生物完整性,客观有效地评价大面积湿地的景观健康。研究表明:大部分健康良好的湿地分布在苏州市郊,受到人类干扰相对较小,相反临近重点开发区域的湿地则退化严重。与其它方法相比,本方法可以有效地评价不同湿地之间的整体健康状况以及单个湿地内部的健康差异情况。在缺少现场观测数据的条件下,仅使用土地利用分类图就可以在短时间内完成对大范围湿地的健康评价。     

张掖市黑河流域湿地资源调查与分类

通过对典型的干旱半干旱区内陆河流域(张掖市黑河流域)湿地综合分类研究表明:①张掖市黑河流域湿地共有2个大类4个类型13个类别,总面积为210420.42hm2,占全市国土总面积的5.02%;②湿地类型和面积从大到小依次为:高山湿地、永久性河流、灌丛湿地、草本沼泽、泛洪平原、内陆盐沼、季节性河流、蓄水区、灌溉区、盐田、永久性淡水湖、池塘、季节性淡水湖;③在行政区域内,肃南县、高台县、临泽县、山丹县、民乐县、甘州区湿地面积分别占全市湿地面积的73.71%、8.29%、5.14%、4.87%、5.54%和2.44%。     

Antiquity of aridity in the Chilean Atacama Desert

The Atacama Desert of northern Chile and southern Peru has one of the longest histories of arid conditions known. Although most studies have focused on the hyper-aridity prevalent since the Miocene, all terrestrial sediments in the region from the late Triassic onwards also record evaporitic and thus arid climates. Supergene mineralization in the region did not develop under a more humid climate conducive to deep weathering, but under arid conditions. These processes may have been facilitated by hydrological changes during Miocene uplift and drainage incision, but were operational prior to the uplift. Similarly, global cooling and changes to oceanic circulation in the post Miocene period only accentuated existing conditions. A whole regolith perspective is vital to understanding the history of aridity in the Atacama Desert and its relevance to arid zone morphogenesis, regolith formation, and supergene mineralization. In particular, the long history of aridity raises the possibility that supergene mineralisation, under the appropriate conditions, form in arid environments, instead of requiring humid conditions.     

干旱区水污染控制工程费用函数研究--以新疆为例

水资源的合理有效利用是西部大开发中极为关键的环节，水污染控制系统规划是其重要组成部分。经济模型是污染控制系统规划的基础。针对干旱区的实际，根据调查资料，进行了干旱区水污染控制工程费用函数的分析计算。由于地区社会经济发展、自然条件、地理位置以及废水处理设施的规模、效率等对经济模型的建立都有较大影响，有必要建立干旱区水污染控制工程费用函数，以适应干旱区可持续发展的需要。     

Trade-offs between food availability and predation risk in desert environments: The case of polygynous monomorphic guanaco (Lama guanicoe)

Habitat selection by ungulates is determined by the quantity, quality and distribution of trophic resources as well as by predation risk. It may also vary in relation to species-specific reproductive strategies and social organization. The guanaco (Lama guanicoe), a highly social and sexually size-monomorphic wild camelid typical of arid lands, is ideal for evaluating behavioural responses of this type, since most studies have done on dimorphic ungulates in temperate environments, where trophic resources are abundant. We recorded the group size and social structure of guanaco during both dry and wet seasons of 2005–2007 in an Argentinean desert, where pumas (Puma concolor) are the sole predators. Remote sensing data were used to calculate five variables that reflected trophic availability and terrain morphology for each guanaco group and for an equivalent number of random controls. Habitat use did not differ between types of social groups but differed between seasons. Guanacos used less productive and less steep areas during the breeding season, irrespective of juvenile:adult ratios in the family groups, and larger groups occupied flatter areas. Overall, guanaco habitat selection prioritizes reducing predation risk to the extent that animals occupy areas offering the minimum productivity capable of meeting their energy requirements.     

中国沙漠和沙地的资源优势与农业发展

人口、粮食、土地之间的矛盾已成为今后我国几十年的主要问题。我国后备土地资源的68%分布在干旱、半干旱地区,其中沙漠和沙地面积辽阔,类型繁多,涉及212个县(旗)、48×106人。我国的沙漠和沙地具备适度开发利用的水资源依托,具有灌溉、雨养和高寒农业等特殊环境,是栽培作物和养殖家畜的集中区,许多尚无饲养或尚无栽培种类可以取代的野生动植物具有独特经济价值和高度的抗性。我国的沙地持续利用技术体系已初步建立,形成了一整套具有中国特色的流沙固定技术,结合各地的具体条件创建了许多成功的区域开发治理模式。沙漠和沙地开发必须摆脱传统的农业利用模式,依靠科技进步,多采光、少用水,结合资源条件、市场需求、投资能力,有计划、有步骤地规模开发。     

1990年以来4个时期四川省湿地的面积、景见旨数及其变化

以1990年、2000年、2010年和2015年的Landsat TM/ETM+/OLI影像为数据源,在遥感和地理信息系统技术的支持下,研究了4个时期四川省湿地的面积、景观指数及其变化。研究结果表明,与1990年相比,2015年四川省的湿地总面积减少了29 744.84 hm^2,其中,沼泽湿地面积减少了63 619.19 hm^2,河流湿地面积减少了27 742.60 hm^2;人工湿地面积增加了63 249.19 hm^2;四川省的湿地主要分布在川西北高原湿地区,最主要的湿地类型是沼泽湿地。随着时间的推移,4个时期四川省的湿地斑块数量、斑块密度和香农多样性指数在波动增大,而最大斑块指数在波动减小,面积加权平均斑块分维数变化不大;四川省的湿地向斑块破碎化、形状规则化和类型多样化方向发展。     

Preliminary characterization of some Argentinean Artemia populations from La Pampa and Buenos Aires provinces

Artemia populations were sampled in four hypersaline ecosystems in continental evaporitic basins from the Argentinean provinces of La Pampa and Buenos Aires. Biometrics of cysts and nauplii were performed. The morphometrics of adult females under standard culture conditions, studied by multivariate discriminant analysis, provided evidence that these populations belonged to the speciesA. persimilis; this was further supported by cross-breeding tests established between one of these populations (Salinas Grandes de Hidalgo, province of La Pampa) and a population ofA. franciscana from San Francisco Bay (California, USA), which showed reproductive isolation and barriers to gene flow between both populations.     

两种干湿气候类型评价方法在内蒙古地区应用比较

Holdridge可能蒸散率(PER)和徐文铎湿润指数(HI)在内蒙古地区的应用结果表明:两种干湿气候类型划分差异主要体现在半干旱和亚(半)湿润区,其余气候类型地域分布比较一致。其年代变化的共同点是半干旱区+干旱区+极干旱区面积逐年增加,亚(半)湿润区+湿润区面积逐年减少。PER分类与降水量分布规律明显,而HI分类更多体现了温度和降水的综合影响。在考虑下垫面特征的情况下,徐文铎湿润指数更符合内蒙古地区干湿气候带划分。30 a温度与降水相关分析表明:温度呈显著增加趋势,而降水的下降趋势属正常气候波动。