Quantitative assessment of tidal wetlands using remote sensing

Effective management of tidal wetlands requires periodic data on the boundaries, extent, and condition of the wetlands. In many states, wetlands are defined wholly, or in combination with other criteria, by the presence of particular emergent halophytic plants. Many important characteristics of the wetlands ecosystem are related directly to the production of emergent plant material or may be inferred from knowledge of the distribution of emergent plant species. Remote-sensing techniques have been applied to mapping of the distribution of wetland vegetation but not to quantitative evaluation of the condition of that vegetation.Recent research in the tidal wetlands of Delaware and elsewhere has shown that spectral canopy reflectance properties can be quantitatively related to the emergent green biomass ofSpartina alterniflora (salt marsh cord grass) throughout the peak growing season (April through September, in Delaware). Periodic measurements of this parameter could be applied to calculations of net aerial primary productivity for large areas ofS. alterniflora marsh in which conventional harvest techniques may be prohibitively time consuming. The method is species specific and, therefore, requires accurate discrimination ofS. alterniflora from other vegetation types. Observed seasonal changes in species spectral signatures are shown to have potential for improving multispectral categorization of tidal wetland vegetation types.     

Soil and plant characteristics of landfill sites near Merseyside,England

An ecological survey of the plant and soil characteristics was carried out on three landfill sites near Merseyside, England. It was discovered that bare ground at two of the landfill areas had high levels of methane contained in the soil air (Sefton Meadows landfill: 6–8% at 35 cm and 16–35% at 65 cm below soil surface; Coalgate Lane landfill: 1–24% at 35 cm and 39–45% at 40 cm below soils surface), causing the appearance of dark grey reduced regions in the soil, a phenomenon similar to flooded soil. The wellvegetated areas at the two sites had lower levels of methane (under 7%).In areas relatively free of methane, the concentrations of mineralized N and NO₃ ^– had significant correlations with the dry weights of vegetation (r = 0.71 withp<0.01;r=0.61 withp<0.02 accordingly), indicating the necessity of applying available nitrogen fertilizer.     

大亚湾核电站运转前及运转后大鹏澳海域水质状况评价

根据大亚湾核电站运转前及运转后对大亚湾大鹏澳海域的监测资料，选用ｐＨ，ＤＯ，ＣＯＤＭｎ，ＴＩＮ，ＰＯ４－Ｐ和Ｃｈｌ．ａ为评价因子，以水质质量综合系数（ＷＱＩ）为模式，评价了大鹏澳海域水体质量状况。综合评价的结果显示，大鹏澳海域水体质量，在核电站运转前及运转后，冬，夏季节均属清洁水平。     

植物净化空气中汞污染的研究

对上海市常见易生长的22种植物进行了现场采样测试，结果发现，瓜子黄杨、广玉兰、海桐、蚊母、墨西哥落叶杉及棕榈对汞蒸气具有很强的吸收富集能力及抗毒性能．然后采用富集能力最强的瓜子黄杨进行一系列试验，结果显示，汞浓度随接触瓜子黄杨时间的延长而降低，而瓜子黄杨叶片的汞含量随时间的延长而增加。根据吸汞实验，计算得瓜子黄杨叶面积的吸气速率为0.133m     

二氧化硫对植物生理生化的影响

通过对北方地区常见草坪品种———阿尔冈金、可奇思、猎狗、派尼等进行SO2 静态熏气处理,然后采用生理生化方法测定不同品种草坪在不同熏气浓度(浓度分别为大气中浓度的10 倍、20 倍、30 倍、40 倍)下体内生理生化指标———过氧化物酶(POD)、超氧化物歧化酶(SOD)、抗坏血酸氧化酶(ASO)、多酚氧化酶(PPO)等酶活力的变化,进而挑选出对SO2具有抗性的品种。     

小龙潭电厂煤灰渣天然放射性调查研究

对小龙潭电厂煤灰渣中天然放射性核素含量、空气中氡及子体水平及外照射空气吸收计量率的研究一经们不能直接用于民用建材，仅用用于公用或露天工程，若与其它低放射性材料适当掺和。则可明显提高射防护的安全性。     

南岳森林群落生物多样性研究(Ⅵ)上封寺森林群落植物物种相对多度分布格局

本文应用几何级数分布、分割线段、对数级数分布和对数正态分布等4种模型研究了南岳上封寺森林群落植物物种相对多度的分布格局。结果表明,几何级数分布模型适宜拟合乔木层和草本层,而不适宜于灌木层;分割线段模型适宜于乔木层,其中,多度一频度模型还适于草本层;对数级数分布模型完全适宜于拟合任何层次;对数正态分布模型仅适宜于拟合乔木层。此外,α-指数值介于季雨林-稀树草原之间。     

上海城市绿地系统建设与规划的原则和对策

针对上海城市绿化现状，强调生态位、生态效益、生物多样性、空间布局和景观割裂等原理在绿地中的重要性，并在此基础上分析探讨了２１世纪的上海在绿地系统建设中应如何提高绿化数量、改善绿地质量、提高生物的多样性和空间异质性、发挥生态效益、丰富绿化形式等诸多问题，尝试为今后的规划提供一些对策。     

Long-term climate variability at the Waste Isolation Pilot Plant,southeastern New Mexico,USA

The United States Department of Energy is developing the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico for the disposal of transuranic wastes generated by defense programs. Because changes in climate during the next 10,000 years (10 ka) may affect performance of the repository, an understanding of long-term climate variability is essential for evaluating regulatory compliance. Fluctuations in global climate corresponding to glaciation and deglaciation of the northern hemisphere have been regular in both frequency and amplitude for at least 780 ka. Coolest and wettest conditions in the past have occurred at the WIPP during glacial maxima, when the North American ice sheet reached its southern limit roughly 1200 km north of the WIPP and deflected the jet stream southward. Average precipitation in southeastern New Mexico during the last glacial maximum 22-18 ka before present (BP) was approximately twice that of the present. Driest conditions (precipitation approximately 90% of present) occurred 6.5-4.5 ka BP, after the ice sheet had retreated to its present location. Wet periods of unknown duration have occurred since the retreat of the ice sheet, but none have exceeded glacial conditions. Global climate models suggest that anthropogenic climate changes (i.e., warming caused by an increased greenhouse effect) will not result in an increase in precipitation at the WIPP. The climate of the last glacial maximum is therefore suitable for use as a cooler and wetter limit for variability during the next 10 ka.     

江西珍稀濒危植物资源与保护

经调查统计，江西分布有国家第一批珍稀濒危保护植物７４种，比《中国珍稀濒危植物》记载本省的种类（４８种）增加了２６种。本文论述了本省珍稀植物濒危的原因和我省自然保护的实际情况，提出了保护、发展和合理利用珍稀濒危植物资源的意见。