Experimental assessment of ecological and phenotypic factors affecting male mating success and polyandry in northern watersnakes, Nerodia sipedon

To resolve conflicting field observations regarding the action of sexual selection, we used breeding experiments and paternity analysis of the 927 resulting offspring to assess how male size, condition, tail length, genetic similarity to the female, and variation in operational sex ratio (OSR) affected male reproductive success and the incidence of polyandry in northern watersnakes (Nerodia sipedon). Only size affected male mating success. Large males were more successful, but only when male size varied substantially and competition among males was intense (i.e., male-biased OSR). The conditional nature of the size advantage may explain why studies of free-living watersnakes have produced inconsistent results regarding the relationship between male size and mating success. Size differences between males did not affect the proportion of offspring each male sired within multiply sired litters. We found positive size-assortative mating, but only when the OSR was female biased, suggesting that smaller males had improved access to females when competition among males was reduced, but that competition with larger males still restricted mating opportunities of small males to less preferred, smaller females. Most litters (58%) were multiply sired and larger females were more likely to produce multiply sired litters, similar to free-living watersnakes. There was no association between the incidence of multiple paternity and OSR, however, suggesting that polyandry is not simply a function of opportunity, with females passively waiting for males to court them.     

Source apportionment and source/sink relationships of PAHs in the coastal atmosphere of Chicago and Lake Michigan

Multivariate statistical techniques were used to investigate source apportionment and source/sink relationships for polycyclic aromatic hydrocarbons (PAHs) in the urban and adjacent coastal atmosphere of Chicago/Lake Michigan in 1994–1995. The PAH signatures for the atmospheric particle phase, surface water particle phase and sediments indicate that atmospheric deposition is the major source of PAHs to the sediments and water column particulate phase of Lake Michigan. The PAH signature for the atmospheric gas phase and water dissolved phase indicate an intimate linkage between the lake and its overlying atmosphere. A modified factor analysis-multiple regression model was successfully applied to the source apportionment of atmospheric PAHs (gas+particle). Coal combustion accounted for 48±5% of the ΣPAH concentration in both the urban and adjacent coastal atmosphere, natural gas combustion accounted for 26±2%, coke ovens accounted for 14±3%, and vehicle emissions (gas+diesel) accounted for 9±4%. Each is an identified source category for the region. These results are consistent with the mix of fossil fuel combustion sources and ratios of indicator PAHs.     

乌鲁木齐地区近代生态环境变化特征

本文从近代社会发展探讨乌鲁木齐地区的生态环境变化特征.指出,自然绿州不断缩小,人造绿州扩大;城市发展迅猛,环境污染加重;地下水位下降;天然森林破坏而导致水土流失和沙化;草场过度放牧,退化严重;野生生物锐减;水资源利用率显著提高,耕灌地大面积增加,由此表明,该区生态环境发展趋势既朝着某些有利于人类发展,也存在某些不利人类发展的方向变化.     

《江苏省生态环境监测条例》解读

简述了《江苏省生态环境监测条例》(以下简称《条例》)出台的重要意义,对《条例》的主要内容和特点进行了解读。《条例》于2020年5月1日正式实施,是我国首部生态环境监测地方性法规,也是落实党中央、国务院深化生态环境监测体制改革的具体举措,弥补了生态环境监测立法的空白。《条例》共分6章47条,重点建立了生态环境监测质量管理、监测机构监督管理、网络管理、污染源监测、监测信息公开与共享等制度,明确了统一监督管理、严厉打击监测数据造假等内容。提出,加快补齐监测网络建设、基层监测能力、污染源执法监测、社会监测机构监管等方面的短板,确保监测数据的真实准确,推动监测事业依法、科学、规范开展。     

景观生态学与荒漠生态环境监测

通过对景观生态的阐述,在讨论荒漠生态环境监测的概念、对象、内容、方法和目的的基础上,分析了景观生态学成为荒漠生态环境监测理论和实践的基础的可能性和必要性,指出景观生态学在荒漠生态环境监测中的应用大有可为。     

塔里木油气资源开发的环境影响分析

塔里木石油资源的开发极大地促进了南疆地区社会和经济的发展。但同时也对开发区自然环境造成了一定的影响。深入全面地分析这些影响，制定预防措施，防止由此而引起的生态环境的进一步恶化，这对保障国民经济高速、持续、稳定发展，有着十分重要的意义。     

模糊综合评价在青藏铁路西格段沿线生态环境影响评价中的应用

介绍了模糊综合评价方法,并应用该方法对青藏铁路(西格段)沿线的环境影响,尤其是生态环境影响进行了评价.实例表明,被评价范围内的生态环境敏感性为中等,青藏铁路(西格段)增建第二线的工程对原有地形植被、生态环境造成了一定影响.模糊综合评价方法对于生态环境影响分析与评价具有重要的参考意义和应用价值.     

浅析景观格局分析方法在生态恢复当中的应用

退化生态系统的恢复是一项艰巨任务，它需要考虑到所要恢复的退化生态系统的结构，多样性和其动态的整体性和长期性。退化生态系统恢复所面临的挑战是理解和利用生态演替理论来完成并加速恢复进程。恢复的主要目标是建立一个自维持的，由不同的群落或生态系统组成的能够满足不同需要如生物保护和粮食生产需要的景观。景观生态学关注于大的空间尺度的生态学问题。景观生态学研究方法可以为退化生态系统恢复实践提供指导。在解决退化生态系统的恢复问题时，景观生态学的方法在理论和实践上是有效的。景观生态学中的核心概念和其一般原理斑块形状、生态系统间相互作用、镶嵌系列等都同退化生态系统的恢复有着密切的关系。如恢复地点的选择和适当的恢复要素的空间配置。在评价退化生态系统的恢复是否取得成功，利用景观生态学也具有重要的意义。景观生态学理论如景观格局与景观异质性理论，干扰理论和尺度理论都能够指导退化生态系统的恢复实践。同样地，景观生态学的许多研究方法对于生态恢复的方案确立、方法实施等都具有明确的指导意义。景观生态学思想与方法应用于退化生态系统恢复过程是一种新的有效途径。     

生态园林与城市环境保护

阐述了生态园林的概念以及它在城市环境保护中的重要作用，讨论了在实施生态园林计划中如何保护、治理城市环境的一些措施，包括城市自然性的恢复，城市的逆境治理和城市的生物多样性的保护与发展等。急切呼吁将生态园林建设同建设环境保护有机地结合起来。     

县级生态示范区建设的几点思考

文章分别从内容、对策和措施、实施主体等三方面全面论述了生态示范县建设的内涵,分析了海安县建设生态示范县的重要性,结合海安县实际,突出海安特色,探讨了建设生态示范县的重点应放在生态农业建设、生态工业建设、生态城镇建设、农村五禁工程、生态文化建设等上,提出了相应的行政、法律、经济、技术保障措施以推动示范县的建成.