Characterization of the fishery in river communities in the low-Solimões/high-Amazon region

Questionnaires were used to collect data from the low-Solimões/high-Amazon region, Brazil, between December 1992 and February 1994. Gillnets, fishing rods and castnets were the preferred gear used. Gillnets were used throughout the year whilst other gears were used only in certain periods of the year. The fish caught tended to supply family needs but a high proportion were sold in regional markets. Curimatã (Prochilodus nigricans), pacu (various Myleinae) and ruelo (young Colossoma macropomum) were the most frequent species caught. Around 50% of the fish caught in these fisheries was consumed fresh, and the remainder was stored under ice or salted. Fish is the most important source of animal protein for this region, with an annual mean consumption rate of 550 g capita^?1 day^?1. The fishery has changed from a subsistence to a commercial scale, which was associated with increasing cattle ranching activities. This may have serious social and economic implications.     

内陆盐碱的成因及防治对策

地处内蒙高原的河北省内陆河流域；土壤盐碱化使本来就十分脆弱的环境变得更加恶劣，严重制约着当地经济的发展，通过对大清沟内陆河流域的地形、水文地质和土壤水盐的研究，初步论述了内陆盐碱的成因及防治对策，即在上中游建梯田和挖水平工程，节节拦蓄地表径流，减缓水盐向下汇集；下游实行井沟排水、井渠灌溉冲洗、降雨淋洗及生物改良等综合防治和利用措施。     

内陆河流域水资源分配的二层性及其优化分析

本文利用二层系统最优化理论，提出了内陆河水资源优化分配的二层动态规划方法及其数学模型，以黑河流域为例，验证了该方法的有效性。     

中小城市环城游憩地开发原则与模式研究——以河北省保定市为例

介绍了环城游憩地的定义与类型,分析了中小城市环城游憩地的开发原则,并以保定市为例,进行实证分析,提出了保定市环城游憩地的开发模式。     

The occurrence of inland acid sulphate soils in the floodplain wetlands of the Murray–Darling Basin,Australia, identified using a simplified incubation method

From 2006 to 2010, low water levels resulted in the drying of previously submerged inland acid sulphate soils (IASS) in wetlands of the Murray–Darling Basin (MDB). The potential for widespread severe acidification resulting from the oxidation of pyrite in these wetland soils triggered a basin‐wide study to assess the occurrence and risks posed by IASS material in the floodplain wetlands of the MDB. The results of pH measurements before and following soil incubation from more than 7200 samples (representing ca. 2500 profiles from 1055 georeferenced wetlands) were used to assess the potential occurrence of sulphuric and sulphidic material in IASS across the MDB. Their occurrence was investigated on a regional basis by dividing the MDB into 13 geographical regions whose boundaries roughly follow hydrological catchment boundaries. A total of 238 floodplain wetlands, representing 23% of the total wetlands assessed, were found to contain soils that became ultra‐acidic (pH < 4) when oxidized and therefore present a severe acidification hazard. These soils, the majority of which are likely to be IASS materials, were found in 11 of the 13 geographical regions. Among the 11 geographical regions likely containing IASS materials, the proportion of wetlands that presented an acidification hazard varied between 2 and 52% of those assessed. The geographical regions found to present the greatest acidification hazard were in the southern MDB, downstream of the Murray–Darling confluence, and in catchments on the southern side of the Murray River channel in Victoria. This study provided policy makers with a valuable screening tool, which helped them to identify priority wetlands and regions that required more detailed IASS investigations.     

Strategies for the rehabilitation of the inland fisheries sector in Central Asia

Abstract The dismantling of the Soviet Union and the corresponding independence of the Central Asian states in the early 1990s had severe economic consequences for the Central Asian Region. The transition from command to free‐market economies was (and sometimes still is) accompanied by dramatic contractions in production in virtually all primary resource sectors. However, arguably the most catastrophic and ongoing declines in output were to be found in the fisheries sector. This study shows how a combination of ecological (most notably the introduction of alien invasive species and pollution), economic (increasing abstraction of water for irrigation and power generating purposes), social (increased impoverishment following the removal of employment guarantees) and governance (collapse of local management structures, decrease of support to the sector and deterioration of trade relationships with neighbouring countries) affected fisheries production and consumption in the Central Asian transition economies. In the light of these findings, some general observations as how this decline might be arrested or reversed are provided.     

玛纳斯河流域ET0影响因子分析及对Hargreaves法的修正

准确估算作物蒸发蒸腾量对于农业水资源的规划和指导农田灌溉非常重要。该文以具有典型内陆河特征的玛纳斯河流域为例,根据1953-2008年的气象资料,采用Penman-Monteith(PM)法计算了流域内参考作物蒸发蒸腾量,并对影响参考作物蒸发蒸腾量的各气象因子进行了通径分析,结果表明在玛纳斯河流域温度是影响参考作物蒸发蒸腾量的最主要因子。以PM法计算得到的参考作物蒸发蒸腾量为标准值,对Hargreaves法计算的参考作物蒸发蒸腾量进行比较分析,结果表明Hargreaves法计算结果偏差较大,在4-10月尤为明显。基于35 a气象资料,采用贝叶斯方法对Hargreaves公式进行修订,采用另外21 a气象资料对修订的Hargreaves公式进行验证,结果显示修正后的Hargreaves公式满足精度要求,且计算简便,可为内陆河流域参考作物蒸发蒸腾量的计算提供参考。     

Soil erosion and hydrological response to land abandonment in a central inland area of Portugal

This paper analyses the effects of land abandonment on runoff and sediment yield in a central inland area of Portugal. Rainfall simulation experiments were performed in areas of traditional land use (land cultivated with cereals) with various types of soil plant cover associated with the period of abandonment (4–5 years, 15–20 years and 30–40 years) in two different seasons, namely under very dry conditions and after a long wet period. Statistical analysis showed a notable difference between the cultivated soils and those abandoned for a long period of time, which included appreciable vegetation recovery, higher organic matter content and negligible overland flow and soil loss. Cereal cultivation, in particular ploughing, is a very negative land management practice, due to the high runoff and soil loss. Within 4–5 years a crust develops over abandoned soils with sparse herbaceous plant cover, particularly after a dry season, which enhances runoff and sediment yield. In scrubland and oak plots, although marked water repellency was registered at the end of a dry, warm season, its influence seems to be irrelevant in terms of overland flow and erosion yield. The major factor in controlling overland flow and reducing soil erosion rates appears to be the role played by vegetation in protecting the soil surface and supplying organic carbon to the top layer. Copyright © 2010 John Wiley & Sons, Ltd.