WATER QUALITY TRENDS AT INFLOWS TO EVERGLADES NATIONAL PARK1

ABSTRACT: Water quality data collected at inflows to Everglades National Park (ENP) are analyzed for trends using the seasonal Kendall test (Hirsch et al., 1982; Hirsch and Slack, 1984). The period of record is 1977–1989 for inflows to Shark River Slough and 1983–1989 for inflows to Taylor Slough and ENP's Coastal Basin. The analysis considers 20 water quality components, including nutrients, field measurements, inorganic species, and optical properties. Significant (p<0.10) increasing trends in total phosphorus concentration are indicated at eight out of nine stations examined. When the data are adjusted to account for variations in antecedent rainfall and water surface elevation, increasing trends are indicated at seven out of nine stations. Phosphorus trend magnitudes range from 4 percent/year to 21 percent/year Decreasing trends in the Total N/P ratio are detected at seven out of nine stations. N/P trend magnitudes range from -7 percent/year to -15 percent/year. Trends in water quality components other than nutrients are observed less frequently and are of less importance from a water-quality-management perspective. The apparent nutrient trends are not explained by variations in marsh water elevation, antecedent rainfall, flow, or season.     

CONSIDERATIONS OF SCALE IN WATER QUALITY MONITORING AND DATA ANALYSIS1

ABSTRACT: An assumption of scale is inherent in any environmental monitoring exercise. The temporal or spatial scale of interest defines the statistical model which would be most appropriate for a given system and thus affects both sampling design and data analysis. Two monitoring objectives which are strongly tied to scale are the estimation of average conditions and the evaluation of trends. For both of these objectives, the time or spatial scale of interest strongly influences whether a given set of observations should be regarded as independent or serially correlated and affects the importance of serial correlation in choosing statistical methods. In particular serial correlation has a much different effect on the estimation of long-term means than it does on the estimation of specific-period means. For estimating trends, a distinction between serial correlation and trend is scale dependent. An explicit consideration of scale in monitoring system design and data analysis is, therefore, most important for producing meaningful statistical information.     

POTENTIAL EFFECTS OF DEVELOPMENT ON FLOW CHARACTERISTICS OF TWO NEW JERSEY STREAMS1

ABSTRACT: Parts of the Raritan River basin in central New Jersey have undergone increasing development over the last several decades. The increasing population relies on the region's ground water and surface water sources for its residential, commercial, and industrial water supply. Urbanization, regionalized wastewater-treatment facilities, stream channel alterations, and interbasin transfers of water can all affect water availability. This pilot study was conducted to determine whether significant trends exist in the base-flow and overland-runoff characteristics of streams in two subbasins with different percentages of urban/built-up land (Anderson et at., 1976). Changes in flow characteristics that could indicate future reductions in safe water yield of the Raritan River basin were examined. Flow and flow variability of the steams draining these two subbasins have increased over time. Many of the flow measures studied experienced pronounced trend shifts about 1960. The cause of these changes cannot be readily determined from the data, nor is it clear whether the increased flow variability lies outside the natural range of flow variability of the streams draining the subbasins.     

海河流域河流空间分布特征及演变趋势

海河流域涵盖我国"京津冀"经济圈,河流对流域内人类生存和经济发展具有重要支撑作用,研究河流空间分布及演变趋势对于合理利用河流水资源、保护河流生态和实现经济可持续发展具有重要意义.本文运用遥感资料的GIS分析方法,对海河流域的河流地貌、水系结构、河流曲率和河网密度、闸坝等指标进行分析,发现:1海河流域河流地貌划分为上游山区段、中部平原段和下游滨海段,3个区段水系形状依次为树枝状(受人为干扰小),编织状(中度人为干扰),稀疏编织状(人为干扰强烈);2流域水库和水闸修建阻断河流纵向连续性,五大水系(滦河、北三河、永定河、大清河、子牙河)连续性指标值低于5;320世纪60年代—80年代—2000年,流域河流平均曲率不断减小,河网密度呈现不定向波动,反映出人为控制对河道形态改变程度大.今后应减少人类活动对河流自然属性的改变,河流治理和修复过程中应充分考虑保护和改造河流地貌、水系结构、河流曲率和河网密度.     

重度富营养化水培条件下烟草的生长特性及其净化效果的研究

研究了烟草在重度富营养化水培条件下的生长特性、根的解剖结构,对其净化效果进行了观测,并对烟草在重度富营养化水中的生长特性变化原因、适应机理进行了探讨。     

金沙江流域(云南部分)生态潜力及其变化

植被景观要素的生态潜力能够反映某区域内生态功能的综合潜力,研究植被景观要素的生态潜力可望为该区域的生态保护工作提供参考。金沙江流域是我国西部的生态脆弱区,因此选择本流域的云南省部分地区进行植被景观要素的生态潜力与变化研究。首先,对流域内各植被类型进行生态潜力的分级与打分;然后,采用1996与2006年的TM遥感数据,制作了流域内的两期植被分类图,并在此基础上,借助ArcGIS软件绘制了生态潜力图;最后,根据流域内10年期间的植被类型变化面积,计算出流域内生态潜力的变化量。分析得出,流域内生态潜力变化最大的为中、东部地区,而该地区正是人口分布比较集中的地区。研究成果一方面可望加强人们认识流域内植被的生态功能和保护价值,以及植被的发展和破坏趋势;另一方面为流域内植被的恢复方向和重点提供可靠的依据.     

Implications of sea level rise for coastal dune habitat conservation in Wales,UK

The potential impact of future sea level rise and climate change on 15 Welsh coastal dune systems has been investigated. Historical Trend Analysis was undertaken using Ordnance Survey maps to quantify past shoreline change and to permit extrapolation of past trends to predict possible future shoreline positions by 2080–2100. Predictions were also made using the Bruun Rule relationship between sea level rise and shoreline response and an integrated method of assessment, Expert Geomorphological Assessment (EGA), which provides a ‘best estimate’ of future coastline change, taking into account such factors as geological constraints, the nature of past, present and future environmental forcing factors, and known coastal process–response relationships. The majority of the 15 systems investigated experienced a net increase in dune area over the last 100–120 years. Only one (Whiteford Burrows) experienced significant net area loss (>5 ha). EGA predictions suggest that several systems are likely to experience significant net loss of dune habitat over the next century, whilst continued net gain is likely to occur for systems where sediment supply rates remain high. Little net change is predicted in some systems. Considering the 15 dune systems together, it is considered unlikely that net dune habitat loss will exceed net gain over the next 100 years provided that there are no major disruptions to sediment supply and natural coastal processes.     

对全球气候变化原因及发展趋势之浅见

分析了引起全球气候变化的各种可能原因，对温室气体、植被破坏、水汽变化等对全球气候变化的影响作了概括总结，阐述了全球气候变化发展趋势及气候变化预测中应注意的问题。     

广州市不同环境屋顶自然生长的植物多样性分析

通过对广州市不同环境屋顶自然生长的植物进行广泛调查，共记录到维管植物49科109属128种，其中，在污染严重、中等和轻微的环境分别记录到21种、73种和111种。结果表明，植物种类的数量与环境受污染程度成反比，而与周围植物的多少成正比。对植物形态学及生态生物学特征的分析结果表明，屋顶自然生长的植物与地上自然生长的植物相比，植株较矮小，叶片较小，根系较发达，根冠比较大，这是屋顶植物长期适应屋顶特殊环境的结果。通过调查及分析，推荐12种有较好屋顶绿化潜力的植物。     

花椒农林复合生态系统的简化对某些相关因子的影响

对单一种植和复合种植两种模式的花椒林地(即有草模式和无草模式)进行了相关生态因子的对比调查,以评价现存花椒林单一模式的合理性．结果表明,在单一种植模式下,花椒林的高度、地径和冠幅虽显著优于复合模式,但是病虫害严重;两种模式中土壤含水率均是随土层厚度的增加而增大,但是变幅有较大差异：复合模式的变幅较稳定,为7．59%～23．79％;而单一模式的变化较剧烈,为4．73％～49．72％,复合模式的土壤含水率显著高于单一模式．复合模式的昆虫种类、多样性、丰富度和均匀度也明显高于单一模式,其中单一模式中的肉食性和寄生性昆虫种类低于复合模式,而植食性蚜虫数量则高于复合模式,暗示单一模式中天敌的栖境和资源以及特定的食草昆虫与有益菌缺少．讨论认为,杂草在花椒林生态系统中起着重要的生态作用,现存的单一种植模式虽然对花椒的生长和产量有利,但却是以牺牲农林系统的可持续发展以及生物多样性为代价的．表3参9。