海河冲积平原区农用地综合生产能力空间差异

以海河冲积平原区为例,通过典型样点调查建立样点标准粮和相应的农用地自然质量等级指数的函数方程,求算理论生产能力;结合近3a(2003-2005年)的粮食实际产量,分析农用地的粮食增产潜力、农用地利用强度及其整理优势.结果表明:全区耕地粮食理论总生产能力为3.03×107t,远高于近3a1.49×107t的粮食平均实际产量,目前该区粮食安全的耕地资源保障程度较高.通过整理优势分析,划定了区域的不同整理优势级别,整理优势大的区域主要集中在冀中南冲积平原区,受灌溉条件、农田基础设施、管理水平的限制,粮食生产能力的开发程度低,粮食生产有较大的增产空间.     

Restoration of the Kishon River

The Kishon River, which is now an industrial sewage canal, may be turned into a recreational area in two stages, and by approximately 20 million dollar investment.

Stage A: The wastewater is treated in order to avoid polluted effluents from entering the river.

Stage B: The river water is treated in order to turn the river into a recreational area.     

Prairie Landscape Change and Flooding in the Mississippi River Valley

Extensive landscape alteration of prairie in the U.S. from agricultural expansion has reduced waterfowl populations and increased precipitation runoff into regional river basins. Satellite imagery shows that prairie landscapes have been less altered in Canada than in the U.S. Long-term, broad-scale precipitation data indicate that in both countries precipitation has varied widely but has not increased over time. Nevertheless, flow rates of unregulated U.S. rivers have increased, but there have been no detectable changes in flow rates of Canadian rivers. Neither of two competing hypotheses advanced to explain increasing flood magnitudes—climate change and channel confinement—can account for these results. Thus, the increased magnitudes of floods in the Mississippi River Valley over the last several decades may be at least partially related to extensive changes in agricultural land use resulting in reduction of natural upland vegetation and wetland drainage in the upper reaches of this watershed.     

常州平原河网水动力模型构建

针对平原河网水动力状况的特点,利用MIKE11软件包建立了常州市河网水动力模型,并利用常州市13个水文站点1997、1999和2009年实测水位和流量资料对模型参数进行率定与验证.结果表明,河道糙率值在0.020～0.035之间,模型计算值和实测值吻合良好,能够反映河道的主要水动力特征.     

Estimating abundance without recaptures of marked pallid sturgeon in the Mississippi River

Abundance estimates are essential for assessing the viability of populations and the risks posed by alternative management actions. An effort to estimate abundance via a repeated mark‐recapture experiment may fail to recapture marked individuals. We devised a method for obtaining lower bounds on abundance in the absence of recaptures for both panmictic and spatially structured populations. The method assumes few enough recaptures were expected to be missed by random chance. The upper Bayesian credible limit on expected recaptures allows probabilistic statements about the minimum number of individuals present in the population. We applied this method to data from a 12‐year survey of pallid sturgeon (Scaphirhynchus albus) in the lower and middle Mississippi River (U.S.A.). None of the 241 individuals marked was recaptured in the survey. After accounting for survival and movement, our model‐averaged estimate of the total abundance of pallid sturgeon ≥3 years old in the study area had a 1%, 5%, or 25% chance of being <4,600, 7,000, or 15,000, respectively. When we assumed fish were distributed in proportion to survey catch per unit effort, the farthest downstream reach in the survey hosted at least 4.5–15 fish per river kilometer (rkm), whereas the remainder of the reaches in the lower and middle Mississippi River hosted at least 2.6–8.5 fish/rkm for all model variations examined. The lower Mississippi River had an average density of pallid sturgeon ≥3 years old of at least 3.0–9.8 fish/rkm. The choice of Bayesian prior was the largest source of uncertainty we considered but did not alter the order of magnitude of lower bounds. Nil‐recapture estimates of abundance are highly uncertain and require careful communication but can deliver insights from experiments that might otherwise be considered a failure.     

A methodological framework for integrating computational fluid dynamics and ecological models applied to juvenile freshwater mussel dispersal in the Upper Mississippi River

Interdisciplinary research in hydraulics and ecology for river management and restoration must integrate processes that occur over a wide range of spatial and temporal scales, which presents a challenge to ecohydraulics modelers. Computational fluid dynamics (CFD) models are being more widely used to determine flow fields for ecohydraulics applications. In the Upper Mississippi River (UMR), the mussel dynamics model was developed as a tool for management and conservation of freshwater mussels (Unionidae), which are benthic organisms, imperiled in North America, that are inextricably linked with the hydraulics of river flow. We updated the juvenile dispersal component of the mussel dynamics model by using stochastic Lagrangian particle tracking in a three dimensional flow field output from CFD models of reaches in the UMR. We developed a methodological framework to integrate hydrodynamic data with the mussel dynamics model, and we demonstrate the use of the juvenile dispersal model employed within the methodological framework in two reaches of the UMR. The method was used to test the hypothesis that impoundment affects the relationship of some hydraulic parameters with juvenile settling distribution. Simulation results were consistent with this hypothesis, and the relationships of bed shear stress and Froude number with juvenile settling were altered by impoundment most likely through effects on local hydraulics. The methodological framework is robust, integrates Eulerian and Lagrangian reference frameworks, and incorporates processes over a wide range of temporal and spatial scales, from watershed scale hydrologic processes (decades), to reach scale (km) processes that occur over hours or days, and turbulent processes on spatial scales of meter to millimeter and times scales of seconds. The methods are presently being used to assess the impacts of pre- and early post-settlement processes on mussel distributions, including the effects of bed shear stress, and the sensitivity of the location of the host fish when juveniles excyst, on juvenile settling distribution.     

秸秆还田少免耕对冲积土微生物多样性及微生物碳氮的影响

土壤微生物是耕地质量的重要指标,为阐明秸秆还田少免耕对土壤质量的影响及其机理,在成都平原(温江)冲积水稻土区,开展了水稻–小麦/油菜轮作秸秆还田培肥定位试验(2003～2008年),在小麦生长季节,系统研究了土壤耕层微生物数量和微生物生物量的变化特征.结果表明,秸秆还田翻耕与秸秆还田免耕的土壤耕层微生物总量分别增加了51.7%、12.8%,土壤微生物数量增加主要来自土壤细菌数量的增加;从小麦全生育期看,在小麦分蘖期的增加幅度高于小麦播种期和小麦收获后,有利于促进小麦养分吸收与生长发育.秸秆还田少免耕显著增加了微生物生物量,秸秆还田翻耕和秸秆还田免耕处理土壤微生物碳总量分别比对照提高74.1%、25.8%,土壤微生物氮分别提高60.2%和12.1%.秸秆还田循环利用显著增加了土壤微生物数量和生物量,有利于土壤养分循环与转化,有利于提高土壤有机质含量并改善有机质质量,是耕地质量建设的重要途径.     

A Framework for Prioritizing Domestic Animal Breeds for Conservation Purposes at the National Level: a Norwegian Case Study

Abstract: Although encompassing only a handful of species, domestic animals have had profound effects on food production for humankind and on human societies. On a global basis, a large proportion of breeds are currently in danger of becoming extinct in the near future. At this critical time, resources are limited and only a selected number of breeds may be supported by concrete conservation programs. I present a framework to facilitate decision making on a national level as to which breeds to support for conservation. These decisions should be made by a national committee of experts experienced with the different breeds and species. First, they must define the species of interest. Second, they should collate as much data as possible and score each breed for key criteria: degree of endangerment, presence of traits of current economic value, presence of traits of current scientific value, agroecological value in a special landscape, cultural-historical value, and genetic uniqueness. The degree of endangerment is the most important criterion because great uncertainty about the future means that all breeds may have traits of future economic or scientific value, so the main aim should therefore be to minimize loss of breeds. To illustrate use of the framework, I considered breed prioritization in Norway. I compared and scored 45 breeds from 17 domestic animal species for these key criteria and thus identified Norwegian breeds of high priority for conservation.     

永定河(北京段)生态修复工程运行管理机制研究

在充分调查永定河生态修复运行管理现状的基础上,以阈值跃迁、适应性管理为指导,对现有运行管理现状及存在问题进行深入分析。研究发现目前运行管理存在缺乏理论指导,管理权责不明晰,资金来源不明确以及生态监测体系、原水买卖平台缺失等问题。为实现运行管理目标,研究提出从构建基于适应性管理的流域委员会管理模式、确定管理机构权责、管理资金配置及建立生态修复管理评估体系4个方面完善运行管理机制,为永定河生态修复工程的运行管理及北方缺水城市的水生态修复工程运行管理提供参考与借鉴。     

Assessing Suitability for Conservation Action: Prioritizing Interpond Linkages for the California Tiger Salamander

Abstract:  Conservation organizations and public agencies are interested in identifying and prioritizing areas for conservation action, often acquisition or easements. Typically, this requires the use of uncertain data and vaguely defined decision criteria. I developed a decision support system to address these uncertainty issues and assist in evaluating conservation opportunities for the endangered California tiger salamander ( Ambystoma californiense ) in Santa Barbara, California. Functionally defined planning units were used to aggregate data on land suitability, land cover change, salamander presence, and movement risk along potential linkages between breeding ponds. I used a fuzzy-logic-based inference engine to evaluate the planning units and rank the relative suitability of interpond linkages for conservation action. The sensitivity of the rankings was considered with respect to uncertainty in salamander occurrence data and the relationship between land-cover-change threats and site suitability. All linkages were substantially degraded, but five areas were consistently identified with high relative suitability for conservation action despite differences in assumptions and uncertainty in biological data. The combination of functionally defined planning units and a fuzzy-logic-based decision support system provides a general framework for considering the suitability of sites for conservation action.     

Motivations for the Restoration of Ecosystems

Abstract:  The reasons ecosystems should be restored are numerous, disparate, generally understated, and commonly underappreciated. We offer a typology in which these reasons—or motivations—are ordered among five rationales: technocratic, biotic, heuristic, idealistic, and pragmatic. The technocratic rationale encompasses restoration that is conducted by government agencies or other large organizations to satisfy specific institutional missions and mandates. The biotic rationale for restoration is to recover lost aspects of local biodiversity. The heuristic rationale attempts to elicit or demonstrate ecological principles and biotic expressions. The idealistic rationale consists of personal and cultural expressions of concern or atonement for environmental degradation, reengagement with nature, and/or spiritual fulfillment. The pragmatic rationale seeks to recover or repair ecosystems for their capacity to provide a broad array of natural services and products upon which human economies depend and to counteract extremes in climate caused by ecosystem loss. We propose that technocratic restoration, as currently conceived and practiced, is too narrow in scope and should be broadened to include the pragmatic rationale whose overarching importance is just beginning to be recognized. We suggest that technocratic restoration is too authoritarian, that idealistic restoration is overly restricted by lack of administrative strengths, and that a melding of the two approaches would benefit both. Three recent examples are given of restoration that blends the technocratic, idealistic, and pragmatic rationales and demonstrates the potential for a more unified approach. The biotic and heuristic rationales can be satisfied within the contexts of the other rationales.     

Simple Spatial Modeling Tool for Prioritizing Prescribed Burning Activities at the Landscape Scale

Abstract:   Resources for prescribed fire are frequently insufficient to manage public lands for all conservation and resource management objectives, necessitating prioritization of the application of fire across the landscape within any given year. Defining tradeoffs when applying prescribed fire to large landscapes is problematic not only because of the complexity of weighing competing management objectives at the landscape scale, but also because of the difficult nature of independently applying need-to-burn criteria to large areas. We present a case study of a simple modeling process implemented at Eglin Air Force Base in the Florida Panhandle (U.S.A.) to prioritize the application of prescribed fire. In a workshop setting, managers and biologists identified key conservation criteria and landscape management objectives that drive the application of prescribed fire. Remote sensing and other spatial data were developed to directly or indirectly represent all these criteria. Using geographic information system software, managers and biologists weighted each criterion according to its relative contribution to overall burn prioritization, and individual values for the criterion were scored according to how they influence the need to burn. Subsequently, this process has been validated and modified through ecological monitoring. This modeling process has also been applied to the 77,400-ha Blackwater River State Forest, public land adjacent to Eglin Air Force Base, demonstrating its applicability to lands with varying management priorities. The advantages of this model-based approach for prioritizing prescribed fire include the reliance on accessible, inexpensive software, the development of spatially explicit management objectives, the ease of transferability, and clearly stated assumptions about management that may be tested and reviewed through monitoring and public comment.     

Prioritizing sites for conservation based on similarity to historical baselines and feasibility of protection

The concept of shifting baselines in conservation science implies advocacy for the use of historical knowledge to inform these baselines but does not address the feasibility of restoring sites to those baselines. In many regions, conservation feasibility varies among sites due to differences in resource availability, statutory power, and land‐owner participation. We used zooarchaeological records to identify a historical baseline of the freshwater mussel community's composition before Euro‐American influence at a river‐reach scale (i.e., a kilometer stretch of river that is abiotically similar) in the Leon River of central Texas (U.S.A.). We evaluated how the community reference position and the feasibility of conservation might enable identification of sites where conservation actions would preserve historically representative communities and be likely to succeed. We devised a conceptual model that incorporated community information and landscape factors to link the best conservation areas to potential cost and conservation benefits. Using fuzzy ordination, we identified modern mussel beds that were most like the historical baseline. We then quantified housing density and land use near each river reach identified to estimate feasibility of habitat restoration. Using our conceptual framework, we identified reaches of high conservation value (i.e., contain the best mussel beds) and where restoration actions would be most likely to succeed. Reaches above Lake Belton were most similar in species composition and relative abundance to zooarchaeological sites. A subset of these mussel beds occurred in locations where conservation actions appeared most feasible. Our results show how to use zooarchaeological data (biodiversity data often readily available) and estimates of conservation feasibility to inform conservation priorities at a local spatial scale.     

截污后深圳河落马洲段大型底栖动物群落的恢复过程

2000年4月至2002年4月,对截污前后的深圳河落马洲段大型底栖动物进行两周年的季度监测.结果表明,截污前深圳河落马洲段没有发现大型底栖动物;截污后大型底栖动物种数、密度、生物量和种类多样性指数(H′)有随时间推移呈增加的趋势;截污后底泥中硫化物、总氮、总磷随时间推移呈下降趋势.由此可见,截污后深圳河落马洲段大型底栖动物从无到有,种数、密度和生物量从少到多,群落结构处于向多样性恢复的过程中.图6表2参11     

岷江干旱河谷典型地段整地造林效果评估

长期以来通过整地造林去恢复重建植被已在横断山区干旱河谷广为采用,然而这样的实践是否能有效提高植被覆盖率并改善土壤水源涵养能力仍不清楚.选择岷江干旱河谷3个典型地段,调查了多年(7～16 a)后整地造林地上植被覆盖、土壤物理性质以及目的造林树种岷江柏(Cupressus chengiana S.Y. Hu)的保存、生长与结实状况,以评价干旱河谷乡土树种造林成效及造林后的生态效果.结果表明:(1)岷江柏在栽植多年后仍有大量死亡,保存率明显下降,造林16 a后仅为38%;(2)不同年代栽植的岷江柏在造林后2～6 a即开始旱现直径年生长量下降趋势;(3)造林带内乡土植被总盖度、灌木盖度、草本盖度、地衣苔藓盖度均低于保留带,因此等高线水平沟整地造林措施未能有效促进乡土植被发育;(4)造林带土壤水分物理性质也不如保留带,整地造林也没有有效改善土壤水源涵养能力.综合分析发现,整地造林多年后岷汀柏造林不仅没有达到岷江干旱河谷预期的生态恢复重建效果,甚至有加剧生态退化的趋势.因此认为:(1)规模化整地造林并不是有效的干旱河谷生态恢复和保护措施;(2)尽管岷江柏是乡土树种,但并不是干旱河谷植被恢复的适宜种.图3表3参29     

A Spatially Explicit Decision Support Model for Restoration of Forest Bird Habitat

Abstract:  The historical area of bottomland hardwood forest in the Mississippi Alluvial Valley has been reduced by >75%. Agricultural production was the primary motivator for deforestation; hence, clearing deliberately targeted higher and drier sites. Remaining forests are highly fragmented and hydrologically altered, with larger forest fragments subject to greater inundation, which has negatively affected many forest bird populations. We developed a spatially explicit decision support model, based on a Partners in Flight plan for forest bird conservation, that prioritizes forest restoration to reduce forest fragmentation and increase the area of forest core (interior forest >1 km from "hostile" edge). Our primary objective was to increase the number of forest patches that harbor >2000 ha of forest core, but we also sought to increase the number and area of forest cores >5000 ha. Concurrently, we targeted restoration within local (320 km²) landscapes to achieve ≥60% forest cover. Finally, we emphasized restoration of higher-elevation bottomland hardwood forests in areas where restoration would not increase forest fragmentation. Reforestation of 10% of restorable land in the Mississippi Alluvial Valley (approximately 880,000 ha) targeted at priorities established by this decision support model resulted in approximately 824,000 ha of new forest core. This is more than 32 times the amount of core forest added through reforestation of randomly located fields (approximately 25,000 ha). The total area of forest core (1.6 million ha) that resulted from targeted restoration exceeded habitat objectives identified in the Partners in Flight Bird Conservation Plan and approached the area of forest core present in the 1950s.     

Area-Based Refinement for Selection of Reserve Sites with the Benefit-Function Approach

Abstract:  Optimization of resource use is necessary for efficient conservation planning. Many reserve-selection algorithms aim to identify representative but inexpensive networks, which may lead to selecting small sites due to their lower costs and collectively higher species richness. Nevertheless, larger sites would be preferable regarding species' long-term persistence. An area-based refinement can be used to overcome this problem. We used a reserve-planning framework in which continuous benefit functions valued representation (numbers of populations), and differential species weights were based on a species' local rarity and threatened status. We introduced a refinement based on the species-area relationship that provides relatively higher values for larger sites. We applied the proposed method to rich fen vegetation in southern Finland. The species-area refinement resulted in a network of significantly larger sites with minor trade-offs with representation (numbers of populations). Giving endangered species higher weights ensured that the trade-off occurred mostly between site size and representation of low-priority species. We recommend using a species-area refinement for practical, maximum-coverage conservation planning.     

A decade of investigations on groundwater arsenic contamination in Middle Ganga Plain,India

Groundwater arsenic (As) load in excess of drinking limit (50 µg L^?1) in the Gangetic Plains was first detected in 2002. Though the menace was known since about two decades from the downstream part of the plains in the Bengal Basin, comprising of Lower Ganga Plain and deltaic plains of Ganga–Brahmaputra–Meghna River system, little thought was given to its possible threat in the upstream parts in the Gangetic Plains beyond Garo-Rajmahal Hills. The contamination in Bengal Basin has become one of the extensively studied issues in the world and regarded as the severest case of health hazard in the history of mankind. The researches and investigations in the Gangetic Plains during the last decade (2003–2013) revealed that the eastern half of the plains, also referred as Middle Ganga Plain (MGP), is particularly affected by contamination, jeopardising the shallow aquifer-based drinking water supply. The present paper reviews researches and investigations carried out so far in MGP by various research institutes and government departments on wide array of issues of groundwater As such as its spatio-temporal variation, mobilisation paths, water level behaviour and flow regime, configuration of contaminated and safe aquifers and their recharge mechanism. Elevated conc. of groundwater As has been observed in grey and dark grey sediments of Holocene age (Newer Alluvium) deposited in a fluvio-lacustrine environment in the floodplain of the Ganga and most of its northern tributaries from Himalayas. Older Alluvium, comprising Pleistocene brownish yellow sediment, extending as deeper aquifers in Newer Alluvium areas, is low in groundwater As. Similarities and differences on issues between the MGP and the Bengal Basin have been discussed. The researches point towards the mobilisation process as reductive dissolution of iron hydroxide coating, rich in adsorbed As, mediated by microbial processes. The area is marked with shallow water level (<8.0 m below ground) with ample monsoonal recharge. The infiltrated rainwater and percolating water from surface water bodies carry organic carbon from sediments (particularly from the clay plugs in abandoned channels), abetting microbial processes, spread of anoxic front and release of As.     

挠力河流域农垦开发中居民地景观生态特征的变化

运用G IS、景观格局分析与聚落分析方法定量分析了挠力河流域在快速农垦开发中居民地分布格局的时空变化,探讨了景观格局形成的机制。景观指数分析表明近50 a来居民地面积和数目激增,居民地斑块面积、聚集度增大,表明人类对挠力河流域景观扰动持续增强。在所有背景地类中,居民地与耕地的邻接比例最高。伴随居民地和耕地迅速扩张,两者邻接比例呈上升趋势,两者相互影响越来越大。不同时期居民地扩张强度高值区分布有所不同,主要分布在早期的耕地新增区,1954—2000年挠力河流域居民地扩张高值区最终主要分布于该流域的西部与中部。虽然居民地数目和面积均激增,各居民地之间的距离亦呈缩短趋势,但居民地最近邻点指数表明,近50 a来挠力河流域居民地分布类型一直为随机分布,农垦经济仍占主导地位,人为规划比城镇发达地区薄弱。