甘肃省民勤沙区土壤结皮理化性质研究

以甘肃民勤沙区为研究区域 ,分别采集了不同地貌部位和不同植被类型下的土壤结皮 ,并对其理化性质进行了初步分析。从结皮土壤的机械组成、土壤盐分、土壤养分、土壤阳离子交换量等方面来看 ,丘间地状况都明显要优于灌丛沙包。这可能与丘间地地形低洼 ,有利于土壤物质汇聚 ,以及其接受的大气降尘远较灌丛沙包为多有关。对于灌丛沙包来讲 ,白刺沙包在理化性质上 ,其状况要优于红柳结皮和梭梭结皮 ,这主要与其对环境的适应性及其所处的演替阶段有关。从目前的植被演替情况来看 ,白刺是当地的顶极种群 ,最适应环境 ,因此结皮发育状况也好 ;红柳目前已经处于极度退化进程中 ,而梭梭为人工植被 ,人工植被因在演替阶段中不起决定作用 ,故理化性质较差。另外从该研究工作还可以看出 ,对白刺植被采取围封措施之后 ,可以显著地促进结皮的生长发育 ,提高结皮中的有机质、全 N、全 P、速效 N等养分以及 Ca CO3含量。     

区域生态服务价值对土地利用变化的响应——以重庆市沙坪坝区为例

土地利用通过生态进程与服务间的相互作用影响生态系统提供的产品与服务.本研究以重庆市沙坪坝区为例,采用GIS与实地调查,运用Costanza等提出的生态服务价值系数,结合敏感度分析,探讨了区域生态服务价值对土地利用变化的响应.结果表明,重庆市沙坪坝区在1992～2002年间生态服务价值从1.74×10⁷ ＄降低到1.68×10⁷ ＄,净损失5.40×10⁵ ＄,平均土地净损失生态服务价值13.62＄·hm^-2;赋予各种土地利用类型生态服务价值系数的大小对区域总的生态服务价值变化影响不明显,其变化趋于相对稳定;耕地、林地和园地生物量生态服务价值系数总和接近于区域真实值,水域生态服务价值系数偏大,调整30%为每年5 667＄·hm^-2,更接近于真实值;运用现状数据库、变更数据库和Costanza模型估算区域土地利用变化导致生态服务价值变化切实可行,可为区域土地利用效益评价及土地利用规划提供借鉴.     

甘肃高台早白垩世下沟组轮藻化石

本文报道了甘肃省高台县马营河剖面下沟组上部轮藻化石5属6种、1相似种和1未定种：Clypeator jiuquanensis (S. Wang) L. Grambast, Aclistochara huihuibaoensis S. Wang, A. cf. huihuibaoensis S. Wang,Mesochara stipitata (S. Wang) Z. Wang, Mesochara crassistipitata Zhang et Meng, Peckisphaera paragranulifera(S. Wang) Fu et Lu, Sphaerochara valida (Z. W. Li) comb. nov. , Sphaerochara sp.。讨论相关种的国内外地层分布,将下沟组上部地质时代归为早白垩世巴雷姆期。     

黑龙江省甘南县旧石器地点发现的新材料

黑龙江省的旧石器考古发掘与研究始于上世纪30年代,迄今为止已有正式报道或发表的遗址和地点100余处,分布在黑龙江省境内各处,年代上均属于旧石器时代晚期.2017年初,根据齐齐哈尔市查哈阳农场群众提供的线索,笔者等在甘南县环太平湖水库周边发现多处旧石器地点以及原料产地.经对该地区的踏勘调查和对一处地点的小规模剖面清理发现...     

生态治理政策工具对农户行为的影响差异研究——以宁夏盐池县为例

政策工具被认为是政府为解决某个公共问题采取的具体手段或措施,一项政策可以视作目标和多种政策工具的组合。在生态治理过程中,不同政策工具对农户行为的刺激程度不同,进而导致不同的政策效果。分离不同政策工具的影响,可为工具选择和政策优化提供科学参考。以盐池县为例,利用基于该县1983-2017年内出台的316份生态政策文本构建的政策工具数据集和VAR模型中的脉冲响应和方差分解方法定量研究了强制型、混合型和自愿型三大类政策工具及十种子工具对农户耕作、放牧、造林3种行为的影响。结果表明：（1）政策工具对农户行为的影响具有时效性,一般在政策出台后2-3年内影响最大,随后逐渐减小并消失,影响持续时间为7-10年。（2）总体来看,政策工具对农户行为的冲击力度较小,冲击范围在0-0.30之间,说明农户行为还受到其他诸多因素的影响。（3）10年累计影响从大到小依次为强制型、混合型、自愿型,其中直接提供和规制两种子工具的影响最大。放牧行为受到政策工具的刺激最大,耕作行为次之,造林行为最小。（4）直接提供工具对耕作行为具有最大正向影响,最大冲击为0.30;规制工具在短期内抑制牲畜数量增长,而直接提供和补贴工具促进牲畜数量增长,且由于冲击曲线存在正负波动,说明政府与农户在牲畜养殖上存在长期博弈;只有规制工具对造林行为具有积极影响,说明造林更多是在政府的主导下进行。建议充分利用政策工具的短期效应,凸显政府角色,及时做好政策效果评估工作,调整工具组合,助力生态目标的实现。     

澜沧江梯级开发下鱼类支流生境替代效果

作为干流高坝水电开发导致鱼类生境丧失的一种补偿措施,支流替代生境近年来被广泛应用于受工程影响河段的土著鱼类保护,但替代支流发挥怎样的保护效果及干流对其的影响仍不清楚。以实施了澜沧江梯级生境替代的支流基独河与罗梭江为研究对象,并选择了邻近的对照支流,通过对鱼类调查数据的分析对比,揭示了各支流鱼类种类组成与群落结构的差异特征,初步阐明了梯级开发下鱼类支流生境替代效果以及干流工程建设对其的影响。结果表明：澜沧江支流替代生境对干流鱼类具有明显的保护作用,支流生境修复后鱼类物种丰富度明显提高,罗梭江土著鱼类、特有鱼类物种数分别增加了12种、7种,基独河则是7种、2种,替代生境能为澜沧江土著鱼类、部分濒危特有鱼类和洄游鱼类提供完成生活史的关键栖息地。干流对支流生境替代保护有着重要影响,罗梭江、基独河与邻近干流鱼类群落的Bray-Curtis相似性分别为21.76%、10.73%,支流河口段保持“河相”是支流生境替代保护效果可持续的关键。综合考虑生境替代保护的效益与投入,建议今后开展此类保护措施时优先选择库尾河相区的支流。     

四川省北川县两栖爬行动物的物种多样性

1995～2007年对四川省北川县境内多个区域进行野外考察,共采集标本218号,经鉴定共55种,分隶13科34属,其中两栖纲7科13属27种,爬行纲6科21属28种。     

Assessments of contamination and human health risks of heavy metals in the road dust from a mining county in Guangxi,China

A total of 32 road dust samples were collected from mining areas and a control area in Nandan County, Guangxi, in order to investigate the contamination characteristics of heavy metals and associated health risks to local residents. The results indicated that elevated concentrations of As, Cd, Cu, Pb, Sb, and Zn were found in road dust in mining areas compared with control areas and background values. Pearson's correlation analysis and principal component analysis indicated that As, Cd, Cu, Pb, Sb, and Zn in road dust mainly originated from anthropogenic sources (e.g., vehicles emission, mining activities, and smelting activities), whereas Cr, Co, and Ni were associated with natural sources (e.g., soil weathering). Furthermore, noncarcinogenic hazards to both adults and children were found in mining areas, while noncarcinogenic health risks in the control area were negligible. The health hazard was mostly ascribed to the ingestion, followed by the dermal contact, and the inhalation. The cancer risks from As, Cd, Co, Cr, and Ni in all studied areas were within safe levels as the R values were below the threshold of 1 × 10^?6.     

Post‐Hurricane Regeneration of Pioneer Plant Species in South Florida Subtropical Hardwood Hammocks1

After Hurricane Andrew crossed southern Florida (U.S.A.) on 24 August 1992, native and exotic pioneer species in subtropical hardwood forests (hammocks) regenerated from seed banks. Regeneration occurred in hammocks of metropolitan Dade County and the Long Pine Key region of Everglades National Park. The density of the native pioneer Trema micrantha was significantly higher in hammocks of Long Pine Key than in those of metropolitan Dade County. In contrast, the basal area of the exotic pioneer Carica papaya was greater in Dade County hammocks than Long Pine Key hammocks. Although T. micrantha tended to be restricted to areas of soil disturbance (tip‐up pits) formed by trees uprooted during Hurricane Andrew, especially in Long Pine Key, C. papaya was located throughout hammocks. These results suggest differences in the regeneration niches in which the native T. micrantha required more specific disruptions (i.e., both canopy and soil) than C. papaya (only removal of canopy) for establishment. A broad regeneration niche could in part account for the capability of an exotic species with a dormant seed bank to invade native subtropical forests following natural large‐scale disturbances.     

Additional fish recordsfrom the Judith River Formation (Campanian) of Montana

The recent recovery of additional fish remains from several fossil sites in Blaine County. Montana, allows us to add a new species of selachian and the occurrence of two genera of Chimaeriformes to the total vertebrate faunal assemblage of the Judith River Formation (Campanian).The new selachian genus is: Chiloscyllium missouriensis, a representative of the family: Orectolobidae.In association with the new orectolobid, there are representatives of the Chimaeroids: Ischyodus bifurcatusCase, and Elasmodus cf. greenoughiAgassiz.These new additions increase the total vertebratefaunnal assemblage of the Judith River Formation to twenty species.