厦门某旱地土壤垂直剖面中重金属迁移规律及来源解析

采用ICP-MS和TIMS分析测定厦门市农业区某旱地土壤垂直剖面中8种重金属元素(V、Cr、Co、Ni、Cu、Zn、Sr和Pb)含量及铅锶同位素组成,重点分析土壤剖面金属的纵向分层和淋失迁移特征.结果表明,除Sr外,其余重金属在大部分剖面深度中均未超过背景值,表明受外来源的影响较小. Sr在整个剖面的迁移系数均大于0,表明存在不同程度的富集; Zn和Co在近地表处富集; Cr、Ni和Cu在整个剖面中以亏损为主; V和Pb受外来活动的干扰小.淋洗迁移特征分析表明,Sr和Pb淋洗下移较活跃,其下移深度较大,但Pb下移深度低于Sr下移深度.因子分析表明,重金属主要为自然因子的输入,其次为农业活动和交通运输等复杂人为活动的输入.富集因子分析表明,Sr受外源不同程度影响.铅锶同位素组成分析表明,垂直剖面土壤中Pb主要来源于母质层,而Sr除来源于母质层外,还受到复杂人为源的影响,并已有向底层(30～70 cm)迁移的趋势.     

农用地土壤抗生素组成特征与积累规律

选取我国北部典型农副产品生产基地,利用HPLC-MS/MS测定土样中四环素类（tetracycline antibiotics,TCs）、大环内脂类（macrolide antibiotics,MLs）以及磺胺类（sulfonamide antibiotics,SAs）共10种抗生素的残留含量,研究不同种类抗生素的组成及空间分布,并对其分布特征与距养殖场、公路、河流间距离的关系,以及不同种植模式、不同土壤性质对抗生素组成与积累规律的影响进行初步探讨.结果表明,研究区土壤抗生素含量值处于较低水平,但检出率较高,总量的检出率高达100%.研究区土壤抗生素的主要成分为TCs,约占总量的94%,不同抗生素的变异系数较大.区内土壤抗生素的空间分布及积累规律受人类活动强度的影响,其中抗生素含量与距养殖场距离呈显著负相关（P<0.05）;距河流50 m内的样点3类抗生素的检出率均达100%;不同种植模式下抗生素含量的积累规律为：果园 > 菜地 > 菜果混种地,且桃园及露天菜地中抗生素的来源、含量与核桃园、大棚菜地及菜果混种地块有明显区别.研究选用土壤pH、有机质（SOM）,阳离子交换量（CEC）、总氮（TN）、有效磷（AP）、速效钾（AK）表征土壤性质,通过冗余分析显示,土壤pH、SOM、CEC、AP、AK这5种土壤特性对抗生素含量的影响较大,其中AK的影响强度最大,TN的影响则相对较弱.研究认为区内土壤抗生素的组成与积累程度受人类活动及土壤性质的共同作用.     

中国近海沉积物在生源要素循环中的功能

中国近海沉积物中生源要素的含量与其粒度、河流输入等诸多因素有关。一般沉积物粒度由粗到细 ,有机质含量由低到高 ,OC ,N ,P的含量递增 ,S和Si含量递减。沉积物的生物地球化学环境涉及到Eh ,pH ,温度 ,OC含量 ,Fe3 /Fe2 值 ,水动力条件 ,沉积物的颗粒大小和间隙水的S体系 ,以及生物扰动等因素 ,它们影响着沉积物中生源要素的早期成岩过程和循环。一般而言 ,中国近海沉积物—海水界面S2 -,HS-,H4SiO4,PO43 -,NH4 的扩散通量是从沉积物向上覆水 ,而SO42 -,HCO3 -,NO3 -,NO2 -的扩散通量从上覆水向沉积物中扩散。生物扰动对沉积物—海水界面生源要素的循环起重要作用。     

三里洞矸石废弃地人工植被群落构建初探

对矸石土样及植被材料进行采样测定,研究分析矸石的供肥能力、微量有毒元素含量、矿区植物中微量有毒元素的含量。研究结果表明:刺槐(Robinia pseudoacacia)对Cu、As元素吸收能力大于其它植物;荠菜(Capsella bursapastrois)对Zn元素的吸收能力较其他植物强;狗尾草(Setaria viridis)对Cr元素具有较强的吸收能力。依据矸石废弃地立地类型特点,矸石废弃地人工植被景观恢复过程中应选择臭椿(Ailanthus altissima)、刺槐(Robinia pseudoacacia)作为先锋树种,宜优先选用刺槐×沙棘×荠菜(Robinia pseudoacacia×Hippophae rhamnoides×Capsella)、刺槐×沙棘×狗尾草(Robinia pseudoacacia×Hippophae rhamnoides×Setariaviridis)、臭椿×沙棘×狗尾草(Ailanthusaltissima×Hippophae rhamnoides×Setaria viridis)群落与刺槐林、臭椿林配植模式。运用生态恢复的方法对矸石废弃地进行人工植被景观恢复与重建,恢复其受损伤的生态系统,这对矸石废弃地植被恢复有一定的理论指导意义。     

Dynamics of Carbon Pools and Fluxes in Russia's Forest Lands

The state and results of studies on the carbon cycle of forests on lands of the Russian forest fund (total area 1172 × 10⁶ ha) are analyzed at the federal level. Consideration is given to changes in the areas of different categories of forest lands, the age structure of stands, the pool and deposition of carbon in the phytomass, and the organic carbon pool of soils over the period from 1966 to 1998; the dynamics of activity in the forest industry by years and the extent of pyrogenic transformation of the forest cover between 1990 and 2001; and carbon fluxes associated with forest exploitation, including carbon emission resulting from fires.     

森林的平均价值、分布和边际价值

目前的价值核算体系忽略了森林的质量、分布、功能等至关重要的因素，因而不能真实的反映森林的价值针对当前价值核算的不足，讨论了森林的平均价值、分布以及边际价值，并指出了当前的生态建设应注意的问题。     

Frontiers created by ‘the Others’

ABSTRACT

This paper highlights the colonized perspective, and aims to reflect on the consequences of a predominant perspective of land control and use for Amazonian indigenous people. The demarcation of indigenous territories has been presented by external public actors, the ‘Others’ to explicitly support indigenous people defend their territories. However, demarcation effectively creates a frontier and enclosure which contribute to alienate indigenous people within their new territories. Amazonian groups normally maintain that they belong to the Land, and their historical use of a determined land has been asserted by anthropological studies. But they belong to Land. In contrast, occupying a territory to generate profit allows the exploitation of everything inside it. Every form of extraction helps to reproduce the colonial logic. A key question we need to address is, therefore: Why do the ‘others’ not feel that belonging?     

Road Erosion and Delivery Index (READI): A Model for Evaluating Unpaved Road Erosion and Stream Sediment Delivery

The Road Erosion and Delivery Index (READI) is a new geographic information system–based model to assess erosion and delivery of water and sediment from unpaved road networks to streams. READI quantifies the effectiveness of existing road surfacing and drain placements in reducing road sediment delivery and guides upgrades to optimize future reductions. Roads are draped on a digital elevation model and parsed into hydrologically distinct segments. Segments are further divided by engineered drainage structures. For each segment, a kinematic wave approximation generates runoff hydrographs for specified storms, with discharge directly to streams at road–stream crossings and onto overland‐flow plumes at other discharge points. Plumes are attenuated by soil infiltration, which limits their length, with delivery occurring if plumes intersect streams. Sediment production and sediment delivery can be calculated as a relative dimensionless index. READI predicts only a small proportion of new drains and new surfacing results in the majority of sediment delivery reductions. The model illustrates how the spatial relationships between road and stream networks, controlled by topography and network geometries, influence patterns of road–stream connectivity. READI was applied in seven northern California basins. The model was also applied in a recent burn area to examine how reduced hillslope infiltration can result in increased hydrologic connectivity and sediment delivery.     

Incentive Structure of and Private Landowner Participation in an Endangered Species Conservation Program

Abstract: In the United States, voluntary incentive programs that aid conservation of plant and wildlife species on private lands provide a structural solution to the problem of protecting endangered species by reducing costs and enhancing benefits to landowners. We explored the potential for incentives to encourage landowners to manage land cover for the benefit of endangered songbirds in central Texas (U.S.A.) by asking landowners to indicate their preferences for financial incentives, technical assistance, and regulatory assurances. We identified owners of potential songbird habitat and collected data in face‐to‐face interviews and self‐administered questionnaires. We used a latent‐class stated‐choice model to identify 3 classes of landowners whose choices varied on the basis of their attitudes and perceived social norms: (1) strong positive attitude, perceived social pressure to participate, and willing to participate with relatively few incentives, (2) weak positive attitude, perceived no social pressure to participate, and required strongest incentives, and (3) negative attitude, perceived social pressure not to enroll, and unwilling to participate regardless of incentive structure. Given this heterogeneity in preferences, conservation incentives may increase management of land cover to benefit endangered species on private lands to some degree; however, exclusive reliance on incentives may be insufficient. Promoting conservation on private lands may be enhanced by integrating incentives into an approach that incorporates other strategies for conservation, including social networks and collaborative processes that reinforce social norms.     

Assessing the shelf life of cost‐efficient conservation plans for species at risk across gradients of agricultural land use

High costs of land in agricultural regions warrant spatial prioritization approaches to conservation that explicitly consider land prices to produce protected‐area networks that accomplish targets efficiently. However, land‐use changes in such regions and delays between plan design and implementation may render optimized plans obsolete before implementation occurs. To measure the shelf life of cost‐efficient conservation plans, we simulated a land‐acquisition and restoration initiative aimed at conserving species at risk in Canada's farmlands. We accounted for observed changes in land‐acquisition costs and in agricultural intensity based on censuses of agriculture taken from 1986 to 2011. For each year of data, we mapped costs and areas of conservation priority designated using Marxan. We compared plans to test for changes through time in the arrangement of high‐priority sites and in the total cost of each plan. For acquisition costs, we measured the savings from accounting for prices during site selection. Land‐acquisition costs and land‐use intensity generally rose over time independent of inflation (24–78%), although rates of change were heterogeneous through space and decreased in some areas. Accounting for spatial variation in land price lowered the cost of conservation plans by 1.73–13.9%, decreased the range of costs by 19–82%, and created unique solutions from which to choose. Despite the rise in plan costs over time, the high conservation priority of particular areas remained consistent. Delaying conservation in these critical areas may compromise what optimized conservation plans can achieve. In the case of Canadian farmland, rapid conservation action is cost‐effective, even with moderate levels of uncertainty in how to implement restoration goals.