Effects of Management on Understory Diversity in the Forest Ecosystems of Northern Spain

Pine plantations are an alternative to marginal agriculture in many countries, and are often presented as an option that improves biodiversity. However, these plantations can have adverse environmental effects if improperly managed. To evaluate the effect of forest management practices on biodiversity, the diversity, species richness, dominance and frequency of understory woody plant species in different forests of the Basque Country (northern Spain) were compared. Plantations of exotic conifers (Pinus radiata [D.] Don) of different ages were compared with deciduous forests of Quercus robur L. and Fagus sylvatica L. The effects of different types and intensities of management were taken into account. The differences observed were mainly conditioned by the intensity of forestry management, although the response varied according to forest type and age. In unmanaged pine plantations, the diversity and species richness of the understory increased rapidly after planting (while dominance decreased), remained stable in the intermediate age range, and reached a maximum in plantations more than 25 years of age. Management practices resulted in decreased understory diversity and species richness, as well as greater dominance. This was more pronounced in younger than in older stands. Moderate management, however, favored a greater diversity of the understory in deciduous forests. The species composition of the plantations and deciduous forests were different, the latter having a wider range of characteristic species. Knowledge of how forestry practices influence biodiversity (in terms of diversity, richness, dominance, and species composition) may allow predictions to be made about the diversity achievable with different management systems.     

Integrating Bioassessment and Ecological Risk Assessment: An Approach to Developing Numerical Water-Quality Criteria

Bioassessment is used worldwide to monitor aquatic health but is infrequently used with risk-assessment objectives, such as supporting the development of defensible, numerical water-quality criteria. To this end, we present a generalized approach for detecting potential ecological thresholds using assemblage-level attributes and a multimetric index (Index of Biological Integrity—IBI) as endpoints in response to numerical changes in water quality. To illustrate the approach, we used existing macroinvertebrate and surface-water total phosphorus (TP) datasets from an observed P gradient and a P-dosing experiment in wetlands of the south Florida coastal plain nutrient ecoregion. Ten assemblage attributes were identified as potential metrics using the observational data, and five were validated in the experiment. These five core metrics were subjected individually and as an aggregated Nutrient–IBI to nonparametric changepoint analysis (nCPA) to estimate cumulative probabilities of a threshold response to TP. Threshold responses were evident for all metrics and the IBI, and were repeatable through time. Results from the observed gradient indicated that a threshold was 50% probable between 12.6 and 19.4 g/L TP for individual metrics and 14.8 g/L TP for the IBI. Results from the P-dosing experiment revealed 50% probability of a response between 11.2 and 13.0 g/L TP for the metrics and 12.3 g/L TP for the IBI. Uncertainty analysis indicated a low (typically 5%) probability that an IBI threshold occurred at 10 g/L TP, while there was 95% certainty that the threshold was 17 g/L TP. The weight-of-evidence produced from these analyses implies that a TP concentration > 12–15 g/L is likely to cause degradation of macroinvertebrate assemblage structure and function, a reflection of biological integrity, in the study area. This finding may assist in the development of a numerical water-quality criterion for TP in this ecoregion, and illustrates the utility of bioassessment to environmental decision-making.     

溶解性代谢残余物生成系数的测定

介绍了活性污泥生物反应结构化动力学模型中的一个重要计量参数ｆｓｐ的估值试验原理和方法，以及对城市污水处理厂的污水和污泥进行测定的研究结果。结果表明，采用污泥好氧消化方法测得的ｆｓｐ值为０．０３０－０．０３２，采用分批试验方法测定的值为０．０６３－０．０７５。     

曝气生物滤池处理效能影响因素及其动力学模型的实验研究

设计正交实验,研究不同气水比、水力负荷、pH值对CODo,SS,氨氮去除率的影响,以及COD负荷、氨氮负荷对COD、氨氮去除率的影响。研究发现：气水比、水力负荷、pH值3个因素对CODQ,SS,氨氮去除率的影响的主次关系为：水力负荷〉气水比〉pH值,且在水力负荷为0．5m/h、V（气）：V（水）=3：1,pH值为6～8时COD0,SS,氨氮去除达到最佳水平。COD容积负荷小于15kg/（m3．d）时,COD负荷的变化对COD去除率影响较小,去除率随着进水COD负荷的提高缓慢下降;相比之下,随着COD容积负荷的增加,氨氮去除率呈明显的下降趋势。实验得出：在设定实验条件下,BAF的动力学模型可表示为：lnC/C0=-60.9A/QC0^0.183.     

烟道气生物脱硫技术研究进展

随着环境生物技术的不断发展,烟道气生物脱硫技术越来越受到人们的广泛关注。综述了近年来烟道气生物法脱硫与资源化的研究进展,指出了主要优势技术各自存在的问题,并对未来发展提出了建议。     

生物入侵预测模型研究进展

生物入侵随着全球化进程有进一步加剧的趋势,外来物种已经被视为对本地生物多样性和生态系统功能产生全球威胁的因素之一。生物入侵的影响巨大,开展预测工作以便在一开始就发现并阻止外来种侵入,为生物入侵提供最优化的监测和早期控制手段。为此,本文从环境的可侵入性和外来种的入侵性两个方面综述了目前生物入侵预测模型的研究进展,以便为外来种引入和管理提供依据。     

曝气生物滤池应用于封闭循环海水养殖系统的试验研究

曝气生物滤池是封闭循环海水养殖系统的核心设备。现以封闭循环海水养殖系统中的曝气生物滤池为试验研究对象,考察了曝气生物滤池的挂膜过程及NH3-N初始质量浓度、循环流速、溶解氧（D0）、循环时间及温度对NH3-N去除效果的影响。试验表明,该曝气生物滤池的生物膜成熟快,当曝气生物滤池在正常养殖状态时．水的循环流速为130L／h可达到NH3-N最大去除率;水的循环流速为80IA可应对高浓度NH3-N负荷。在污水DO质量浓度为7．0mg／L,温度为34℃时,滤池有最大的NH3-N去除率。     

基于活性炭吸附的造纸污泥纤维板除臭研究

为造纸污泥纤维板除臭提供依据。使用活性炭吸附对造纸污泥纤维板进行除臭研究,计算在18周内污泥纤维板失重量及失重速度,活性炭增重量及增重速度;同时用嗅觉法测定臭味。发现在18周内污泥纤维板是不断失重,活性炭不断增重。二者质量相差不大,且前3周速度较快。臭味变化是前3周降低较多,有一种发酸的味道,5周后酸味也减少,保持到第18周。活性炭吸附可以减少造纸污泥纤维板臭味,处理3周即可得到较好效果。     

酚醛废水处理技术研究进展

酚醛废水(PFW)含有大量挥发酚和游离甲醛,还含有部分甲醇及少量低分子树脂、大量酸类等有毒物,需经过处理后才可排入环境.其中联合工艺是最为可行的处理工艺.