黄土丘陵沟壑区典型植物耐旱生理及抗旱性评价

通过实地采样获取黄土高原丘陵区柠条、侧柏、油松、山杏和山毛桃5种常见植物类型的4个耐旱指标(丙二醛含量、叶绿素含量、谷胱甘肽含量、束缚水/自由水含量比值)和2个抗旱指标(脯氨酸含量、可溶性糖含量)数据,采用模糊数学隶属函数法和灰色关联分析法评价不同植物的抗旱能力和不同指标的指示效果.结果表明,不同树种的上述6个生理指标对干旱条件的响应存在显著差异,但基于单个指标获得的树种抗旱能力排序结果不完全一致,说明单个指标无法全面描述树种的抗旱能力,对5个树种抗旱能力大小的综合评价结果为柠条＞侧柏＞油松＞山杏＞山毛桃.耐旱指标叶绿素含量、束缚水/自由水含量比值、谷胱甘肽含量和抗旱指标脯氨酸含量与抗旱隶属度的关联度值均＞0.60,可用以指示植物的抗旱能力,其中,以脯氨酸含量的指示效果最好.     

Should Habitat Trading Be Based on Mitigation Ratios Derived from Landscape Indices? A Model-Based Analysis of Compensatory Restoration Options for the Red-Cockaded Woodpecker

Many species of conservation concern are spatially structured and require dispersal to be persistent. For such species, altering the distribution of suitable habitats on the landscape can affect population dynamics in ways that are difficult to predict from simple models. We argue that for such species, individual-based and spatially explicit population models (SEPMs) should be used to determine appropriate levels of off-site restoration to compensate for on-site loss of ecologic resources. Such approaches are necessary when interactions between biologic processes occur at different spatial scales (i.e., local [recruitment] and landscape [migration]). The sites of restoration and habitat loss may be linked to each other, but, more importantly, they may be linked to other resources in the landscape by regional biologic processes, primarily migration. The common management approach for determining appropriate levels of off-site restoration is to derive mitigation ratios based on best professional judgment or pre-existing data. Mitigation ratios assume that the ecologic benefits at the site of restoration are independent of the ecologic costs at the site of habitat loss. Using an SEPM for endangered red-cockaded woodpeckers, we show that the spatial configuration of habitat restoration can simultaneously influence both the rate of recruitment within breeding groups and the rate of migration among groups, implying that simple mitigation ratios may be inadequate.     

土地处理技术在干旱-半干旱过渡带生态建设中的应用

土地处理系统是在干旱 -半干旱过渡区实现污水无害化、资源化的有效技术。内蒙古霍林河矿区污水土地处理系统设计与运行结果表明 ,该区具备推广土地处理技术的良好条件 ,土地处理系统应以慢速渗滤和污水资源利用型为主 ,实现污水处理与生态环境建设的结合。污水资源的利用有助于增加镶嵌型复合生态系统的稳定性 ,加速人工林的成林郁闭 ,增加林木蓄积量 ,改善干旱、半干旱地区的生态环境     

Great Basin Land Management Planning Using Ecological Modeling

This report describes a land management modeling effort that analyzed potential impacts of proposed actions under an updated Bureau of Land Management Resource Management Plan that will guide management for 20 years on 4.6 million hectares in the Great Basin ecoregion of the United States. State-and-transition models that included vegetation data, fire histories, and many parameters (i.e., rates of succession, fire return intervals, outcomes of management actions, and invasion rates of native and nonnative invasive species) were developed through workshops with scientific experts and range management specialists. Alternative restoration scenarios included continuation of current management, full fire suppression, wildfire use in designated fire use zones, wildfire use in resilient vegetation types only, restoration with a tenfold budget increase, no restoration treatments, and no livestock grazing. Under all the scenarios, cover of vegetation states with native perennial understory declined and was replaced by tree-invaded and weed-dominated states. The greatest differences among alternative management scenarios resulted from the use of fire as a tool to maintain native understory. Among restoration scenarios, only the scenario assuming a tenfold budget increase had a more desirable outcome than the current management scenario. Removal of livestock alone had little effect on vegetation resilience. Rather, active restoration was required. The predictive power of the model was limited by current understanding of Great Basin vegetation dynamics and data needs including statistically valid monitoring of restoration treatments, invasiveness and invasibility, and fire histories. The authors suggest that such computer models can be useful tools for systematic analysis of potential impacts in land use planning. However, for a modeling effort to be productive, the management situation must be conducive to open communication among land management agencies and partner entities, including nonprofit organizations.     

Rehabilitation of degraded community lands for sustainable development in Himalaya: a case study in Garhwal Himalaya,India

SUMMARY

An approach to the rehabilitation of degraded community lands built on people's perceptions and traditional knowledge was developed, implemented on a small scale (6 ha plot), and evaluated in terms of economic and ecological costs and benefits over a period of 5 years in a mid-altitude (1200 m) village of Garhwal Himalaya. Rehabilitation comprised establishment of water harvesting tanks, organic management of soil, agroforestry (native multipurpose trees t traditional crops), and decision making by the whole village community. Costs and benefits under irrigated and unirrigated conditions were compared. The total cost of establishing the irrigated agroforestry system was 1.23 fold that of the unirrigated one, whereas the total benefit was 2.09 fold. The average standing above-ground biomass of the 4-year-old plantation in the irrigated agroforestry system was 11.69 t/ha compared to 8.34 t/ha in the unirrigated system. Improvement in soil properties was more pronounced in the irrigated system than in the unirrigated one. Nutrient input, an input derived largely from forest biomass, in the unirrigated system was nearly 3 times higher than that in the irrigated system. It is concluded that, considering the local and national/regional/global interests in an integrated manner, agroforestry incorporating water management would be a more effective option for rehabilitating degraded community lands than the afforestation currently being attempted by the government in the mid-altitudes of Indian Himalaya.     

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.     

制度变迁框架下的耕地生态环境变化研究

从制度安排的角度考察耕地生态环境．通过设计关于农业发展和耕地生态环境的相关指标,从理论和实证角度分析我国建国以来历次制度变迁对农民行为和耕地生态环境的影响。认为土地制度和其他制度决定农民对“用地”和“养地”行为的选择。分析结果表明,不同的制度安排对我国耕地的数量和质量变化呈现出不同效应,地权的稳定性和其他制度会影响农民的用地行为．从而影响耕地生态环境。所以．保护耕地既要严格控制农用地转为建设用地的总量。又要设计适宜的农地产权制度和其他制度以促进农民主动养护耕地。     

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.     

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?