环贵州喀斯特高原湖泊环境中的细菌多样性

采用纯培养方法,选用6种培养基对23份环贵州喀斯特高原湖泊环境土壤样品中的细菌进行分离培养,经初步形态排重后共获得83株细菌纯培养物。菌株的16S rRNA基因序列信息显示,这些菌株归属于3门12目15科19属,优势细菌类群为链霉菌属（Streptomyces）、芽胞杆菌属（Bacillus）、短芽胞杆菌属(Brevibacillus）和北里孢菌属（Kitasatospora）。同时采用高通量测序分析的方法评估了这些土壤样品中的细菌群落结构特征。环境样品中16S rRNA基因的V3~V4区序列分析显示,从土壤样品中检测到分属于17门36目74科130属的细菌,涵盖喀斯特高矿物质环境、盐碱湖泊环境、森林土壤环境中存在的优势菌群,其中变杆菌属(Variibacter)、慢生根瘤菌属(Bradyrhizobium)以及嗜酸栖热菌属（Acidothermus）为优势属,体现出该生境中细菌群落结构的独特性。综合纯培养和高通量测序分析结果,环贵州喀斯特高原湖泊环境样品中细菌群落特征和环境之间存在着明显相关性,其中蕴含着丰富的细菌资源,值得进一步挖掘。     

内蒙古伊金霍洛旗红海子湿地公园鸟类种类组成及生态分布

2012年10月—2013年9月,对红海子湿地公园鸟类资源进行调查。结果表明:共发现鸟类116种,隶属于16目36科,其中,夏候鸟49种,冬候鸟9种,留鸟24种,旅鸟34种;鸟类种类和数量有所增加;依据地形地貌和植被类型,在调查区选择了湿地、林地、草地和居民区4种生境,其中,湿地鸟类多样性指数(3.042)和均匀度指数(0.687)最高,居民区多样性指数(0.599)和均匀度指数(0.227)最低,优势度指数湿地最低(0.079),居民区最高(0.766),相似性指数林地和草地最高(0.667),湿地和居民区最低(0.204);本文对该湿地主要优势鸟种与环境的关系、湿地鸟类种类和数量较前几年增加的原因进行了分析,推测出水质变化可能是导致鸟类疾病发生和死亡的原因。     

丽香铁路建设对沿线景观格局影响的尺度效应及其生态风险

高原铁路作为大型廊道工程,线长点多、途经环境敏感,其对沿线生态环境影响评价范围的界定在环评工作实践中易产生争议.本文以丽香铁路唐布至建塘段为研究对象,利用2012年1∶10000土地利用现状图和数字高程模型为数据源,采用缓冲区与景观指数方法,构建了廊道切割度指数和廊道干扰累积作用指数,改进了衡量铁路建设后的生态风险指数.通过定量分析不同空间尺度下铁路建设前后景观格局时空变化特征和演变规律,得到本段铁路最适宜评价尺度,并在该尺度内对铁路建设前后生态风险时空变化特征进行分析.结果表明：廊道切割度指数有效反映出铁路廊道对各种景观类型的切割方式和程度,廊道干扰累积作用指数可衡量铁路风险源与风险受体之间暴露与危害关系;铁路建设后,铁路廊道将对沿线景观产生较大的正中切割作用,边缘切割和内部切割作用较小,林地和草地所受影响最大;景观格局指数在600 m缓冲区内尺度效应最明显,因此设置600 m为本段铁路最适宜生态影响评价范围;铁路建设前,600 m评价区以低生态风险为主,铁路建设后,生态风险显著增加,以中等以上生态风险区域为主;研究区生态风险具有南低北高,多核环形的分布特征.     

土地利用变化对挠力河流域可溶性有机碳输出的影响

采用野外采样、室内分析、GIS及统计分析相结合的方法,研究了挠力河流域河水可溶性有机碳（DOC）浓度的季节性动态,以及年均尺度上全流域、100 m河岸带土地利用变化对河水DOC输出的影响.结果表明： 基流状态下,河水DOC浓度在春季、夏季显著高于秋季;有湿地存在的子流域DOC浓度的季节性动态与无湿地存在的子流域存在显著差异,且有湿地存在的子流域中DOC浓度的季节性变异与整个流域的趋势一致;年均尺度上,DOC浓度与全流域湿地以及100 m河岸带范围内的水田面积百分比呈显著正相关,而与全流域尺度的林地百分比呈显著负相关（P<0.05）.表明湿地的存在是影响挠力河流域河水DOC季节性变异的重要因素;全流域的湿地以及100 m河岸带范围内的水田对其具有显著的促进作用,而林地对其有显著的减缓效应,流域过去几十年的土地利用变化改变了河水DOC的平衡状况.     

北京典型城市湿地小气候效应时空变化特征

在北京市选择8个典型湿地为研究样本,对水平方向上温、湿度和负氧离子浓度的变化进行测定,研究湿地对城市温度、湿度和负氧离子浓度的影响。结果表明:湿地对城市局部环境具有明显的降温、增湿和增负氧离子浓度的作用,且距离水体越近小气候效应越强,其中温度与距离显著正相关(R2≥0.81,P0.01),而湿度和负氧离子浓度均与距离显著负相关(R2≥0.83,P0.01);与距离湿地5 km处观测值相比,湿地最高可以降温4.4℃,增湿12.8%,增加负氧离子浓度27.2%;湖泊湿地对局部环境的降温和增湿效果比河流湿地的降温增湿效应更加明显,两者分别相差大约1℃和5%左右;因此,从城市规划与建设的角度看,在增加湿地面积的同时,也要根据湿地用途相应地考虑不同的湿地类型,使湿地改善城市生态环境的效应得到充分发挥。     

乐安河—鄱阳湖湿地植物群落特征及其优势植物对重金属Cu、Pb、Cd的富集

选择乐安河—鄱阳湖湿地典型植物群落,采用重要值方法评价各样点植物群落特征并筛选出典型优势植物,通过室内理化测试分析不同生境中优势植物植株及其根区土壤中重金属Cu、Pb、Cd的含量;采用生物富集系数(BCF)方法评价不同优势植物对重金属Cu、Pb、Cd的富集特性。结果表明:研究区湿地植物以草本为主,在各样点共发现124种物种,包括蕨类植物2科2属2种,种子植物40科97属122种,并从中筛选出羊蹄、红蓼、鼠曲草、紫云英、苎麻等5种富集能力较强的优势植物;植物根区土壤中的Cu、Cd含量均超过土壤环境质量三级标准,而且Cu、Cd的最高含量分别为824.03、5.03 mg·kg-1;不同优势植物对Cu、Pb、Cd等3种重金属元素中的1种或2种表现出较强的富集能力,其中优势物种红蓼对Cu具有较强的富集能力,含Cu量最高为148.80 mg·kg-1,另一种优势物种鼠曲草对三种元素的生物富集系数均较高,且对Cd的最高富集含量为15.17 mg·kg-1,对Cd的生物富集系数最高值为19.14,高于其他植物10倍以上,鼠曲草对重金属Cd具有富集植物的基本特征,且对Cu和Cd具有共富集特征并具有较高的耐性,紫云英、羊蹄等对Cd的富集能力也较强。上述5种优势植物种群对鄱阳湖湿地Cu、Pb、Cd等重金属污染物的生态修复具有一定参考价值,可作为鄱阳湖湿地重金属污染修复植物的选择对象。     

羊山湿地发现海南植物新分布

报道了海南植物3新记录种,即水鳖科的虾子草[Nechamandra alternifolia(Roxburgh ex R.Wight)Thwaites]、玄参科的异叶石龙尾[Limnophila heterophylla(Roxburgh)Bentham]和天南星科的菖蒲(Acorus calamus Linnaeus)。3种植物生于未污染的海口羊山湿地中,对生境要求高,其中虾子草和异叶石龙尾分布稀少。因此,可以说明羊山湿地是一块重要的物种分布区域。     

Floodplain conservation in the Mississippi River Valley: combining spatial analysis,landowner outreach,and market assessment to enhance land protection for the Atchafalaya River Basin,Louisiana, U.S.A.

Threats to riverine landscapes are often the result of system‐wide river management policy, located far from where the threats appear, or both. As a result, the rationale for land protection to achieve floodplain conservation and restoration has shifted to require that lands must also have multiple and systemic threat abatement benefits. The Mississippi River Flood of 2011 highlighted the need for increased floodplain complexes along the Mississippi River to provide both systemic threat abatement and conservation benefits. We used spatial analysis, landowner outreach, and market assessment to examine ways to enhance land protection in the Atchafalaya River Basin Floodway, the largest river basin swamp North America and the site of two employed floodway locations during the 2011 flood. We identified six Priority Conservation Areas (77,084 ha) in the floodway that are largely privately owned (mean 78.2 ± 6.4%), with forest dominated by Taxodium distichum (baldcypress) and hydrologic and water quality characteristics considered most suitable for baldcypress regeneration (31.2 ± 2.4% and 10.2 ± 3.0% of area, respectively). Landowners expressed high (80%) interest in land protection programs and found the range of property values derived from market analyzes (minimal protection—$346 USD/ha; additional protections—up to $2,223 USD/ha) to be reasonable. We seek to: (1) enhance current land protection in the Atchafalaya River Basin and (2) provide a model for using land protection to increase the number of floodplains for both systemic threat abatement and conservation benefits.     

Increasing substrate heterogeneity as a bet‐hedging strategy for restoring wetland vegetation

Mimicking the natural heterogeneity of wetland substrates, e.g. by roughening surface soil or constructing hummocks, has been shown to facilitate wetland plant establishment. We asked if incorporating substrate heterogeneity could also help plants withstand variation in moisture levels. In a wetland with Carex stricta (tussock sedge) as the main restoration target, we manipulated substrates to create different soil moisture environments for planted C. stricta plugs. Our artificial mounds mimicked tussocks formed by C. stricta in natural meadows (circa 10–40 cm in height); we also varied mound compositions and created shallow depressions. Monitoring demonstrated variation in soil moisture among our treatments and natural differences in soil moisture between experimental blocks. Additionally, rainfall varied from severe drought in year 1 to extreme rainfall in year 2. Plug survival, flowering, cover, biomass, leaf length, and growth rate all varied with treatment, block, and/or year. Interactions among those factors were common. Planting plugs in shallow depressions exacerbated stress in a wet block during a wet year, causing low survival. Planting plugs in moisture‐retaining peat pots allowed them to survive and sustain growth even in a dry block during a dry year. We conclude that heterogeneous substrates can be used to hedge against environmental variability by widening the range of microsites available within a restoration site and thereby moderating stressful conditions in some areas.     

Long‐term declines in multiple waterbird species in a tidal embayment,south‐east Australia

Worldwide, local extinctions and severe declines in waterbird densities are being reported from many important waterbird sites. Waterbird sites often exist as a network, collectively providing crucial habitat for different life history stages of different species. Therefore, population changes at one site may strongly influence others. In Australia, many waterbird species are highly mobile, and move rapidly over long distances in response to rainfall. Large tidal wetlands often serve as drought refugia or alternative breeding habitat for these species. These sites are also the migration terminus of many species of shorebirds that spend their non‐breeding season in Australia. One such site in south‐eastern Australia is Western Port, a Ramsar‐listed tidal embayment forming part of the East Asian–Australasian Shorebird Site Network. We measured waterbird population trends over nearly 40 years in Western Port to see whether changes showed consistent trends over time across multiple species. Thirty‐nine species were recorded often enough to allow an analysis of trends over time using dynamic linear models and, where appropriate, piecewise linear regression. Twenty‐two species had declined, including four species of duck, five species of fish‐eating bird (cormorants, terns and pelicans), one species each of grebe, gull and heron, and 10 species of shorebird. Only two species (Australian pied oystercatcher Haematopus longirostris and straw‐necked ibis Threskiornis spinicollis) increased significantly over the same time period. Patterns of decline in non‐migratory waterbirds may reflect diminishing wetland availability, local reductions in fish prey, increased predation pressure and changes in inland wetland resources. Declines in migratory shorebirds are most likely related to loss of habitat elsewhere in their trans‐equatorial migration routes. These trends in waterbirds that use Western Port reflect widespread impacts on populations elsewhere in Australia and overseas, necessitating more than simply local management of this tidal embayment.