我国水土流失区面临的挑战及对策研究

回顾15年来水土保持工作历程，我国水土保持生态建设遵循自然规律和经济规律，为水土流失治理区社会经济可持续发展奠定了坚实基础。同时我们也应看到。依照科学发展观的要求、人与自然和谐发展的要求以及生态安全保障的要求。我国的水土流失问题并未得到根本性的遏制，水土保持工作仍旧任重而道远。通过对当前我国水土流失区域基本国情的深入剖析，明确今后水土保持工作面临的挑战，在此基础上构建了以人与自然和谐发展为核心理念的新时期水土保持生态建设战略模式。     

Changes in soil microbial biomass, metabolic quotient, and organic matter turnover under Hieracium (H. pilosella L.)

 In New Zealand Hieracium is an opportunistic plant that invades high country sites more or less depleted of indigenous vegetation. To understand the invasive nature of this weed we assessed the changes in soil C, N and P, soil microbial biomass C, N and P contents, microbial C : N and C : P ratios, the metabolic quotient, and turnover of organic matter in soils beneath Hieracium and its adjacent herbfield resulting from the depletion of tussock vegetation. The amounts of soil organic C and total N were higher under Hieracium by 25 and 11%, respectively, compared to soil under herbfield. This change reflects an improvement in both the quantity and quality of organic matter input to mineral soil under Hieracium, with higher percentage organic C and a lower C : N ratio. The microbial biomass C, N and P contents were also higher under Hieracium. The amount of C respired during the 34-week incubation indicated differences in the nature of soil organic matter under Hieracium, the unvegetated "halo" zone surrounding Hieracium patches, and herbfield (depleted tussock grassland). Decomposition of organic matter in these zones showed that the Hieracium soil had the greatest rate of CO₂ respired, and the halo soil had the lowest. We relate the enhanced organic C turnover to the invasive nature of Hieracium. Net N mineralization was significantly lower from the Hieracium soil (57 mg N g^–1 soil N) than from herbfield and halo soils (74 and 71 mg N g^–1 soil N, respectively), confirming that the nature of organic N in Hieracium soil is different from adjoining halo and herbfield soils. It seems plausible that specific compounds such as polyphenols and lignins released by Hieracium are not only responsible for increased organic N, but also control the form and amount of N released during organic matter transformations. We conclude that the key to the success of Hieracium in the N-deficient South Island high country of New Zealand lies in its ability to control and sequester N supply through modifying the soil organic matter cycle. Received: 1 December 1998     

新形势下新疆国家级贫困县的贫困类型与扶贫对策

新疆国家级贫困县的扶贫开发工作在新形势下具有长期性、艰巨性、复杂性和特殊性。缘于特殊的地理环境和民族构成,反贫困在新疆不仅是经济问题,同时也是社会问题和政治问题。研究发现,新疆国家级贫困县绝大多数都分布在南疆三地州,贫困率较高,少数民族占贫困人口比重居高不下,财政均出现高额赤字,收支矛盾极为突出,对上级财政有着极强的依赖性。新疆国家级贫困县的贫困类型及原因分为六类:生态贫困、地域贫困、民族贫困、文化教育贫困、市场竞争引致性贫困和制度性贫困,并在此基础上从有效整合各种扶贫资源、赋权式扶贫、产业扶贫、科技扶贫、公共服务均等化等方面提出扶贫对策。     

新农村建设中的农村消费市场研究

本文就完善农村消费市场对于农村经济发展的意义,以及农村消费市场在现阶段存在的问题展开分析,在此基础上对完善农村消费市场提出一些可行性建议。     

香茅花叶病的发生及病原鉴定

对香茅花叶病的侵染性、病原形态、物理性质及寄主范围等进行了研究。测定6科40种(品种)植物,发现禾本科的玉米4个品种、高梁3个品种和甘蔗等被侵染发病,表现系统花叶症状。其余5科32种(品种)植物不表现症状。病原钝化温度为55℃,稀释限点为10~(-2)—10~(-4),体外存活期为1d。用病叶粗提纯液制样,在电镜下可观察到许多线状病毒粒子,测量其大小为9.7×750—800nm。在受侵染的叶肉细胞的细胞质中,看到同样的病毒粒子和风轮状或片状聚集体的内含体。结果表明,引起我国香茅花叶病的病原属于甘蔗花叶病毒(SCMV)的一个株系。     

How does the presence of greenspace related to physical health issues in Indonesia?

There have been many studies associating various aspects of greenspaces with physical health. Very few of these investigations are available for developing countries such as Indonesia. Our study focused on evaluating the association between greenspace and the incidence rate of non-communicable diseases (NCDs) in terms of ischemic heart disease (IHD), diabetes mellitus (DM), rheumatoid arthritis (RA), and chronic kidney disease (CKD). Greenspace was presented by satellite-derived normalized difference vegetation index (NDVI) and forest-related green cover datasets to define exposures to the resolution of 250-m. The Institute for Health Metrics and Evaluation provided age and gender incident data of NCDs at the province level. A generalized additive mixed model coupled with sensitivity test was used to evaluate the exposure-outcome association. Stratified analyses were also employed. After adjusting for covariates, there was a significant negative association for incidence of NCDs and greenspace. We found that an interquartile unit increase of NDVI, and a percentage of forest were closely related to a decrease in the risk of NCDs by 0.3–9.4% and 0.6–6.2%, respectively. Stratified by exposure level, a greater effect of greenspace on reducing NCDs risk occurred in high exposure areas. Considering the socioeconomic factors, greenspace could influence on reducing NCD risks in high urbanization, low-high poverty, and low-high literacy areas. An increment unit of greenspace was associated with a decreased risk of NCDs. This study underscores important health benefits associated with exposures to nature supporting efforts to preserve greenspaces in Indonesia.     

Projected large-scale range reductions of northern-boreal land bird species due to climate change

Climate change is projected to be particularly strong in the northern latitudes. Thus, boreal or arctic species are especially susceptible to the effects of climate warming. In this work we forecasted changes in the distributions of 27 northern land bird species in the 21st century, based on predicted rates of climate change. We used climate and bird atlas data of Finland and northern Norway from 1971-1990 to establish bioclimatic envelope models for each species. Next, these models were applied to two climate scenarios (A2 and B1) from the general circulation model HadCM3 to forecast potential future distributions of the study species over a larger area also covering parts of nearby Sweden and Russia. This area stretches through the boreal and continental arctic zone in northern Europe. In the A2 scenario the predicted global change in mean temperature is 3.8 °C by 2100 and in the B1 scenario 2.0 °C. Our results suggest that most of the northern land bird species will lose most of their climatic space by 2080 both in the more severe (A2, average predicted range decline: -83.6%) and in the less severe scenario (B1, average change: -73.6%). A large proportion (over two thirds) of the species considered here is thus susceptible to major range contractions in this geographical region. These climate change-induced threats are of importance because the Arctic Ocean represents a natural barrier for northward movement of species. To reduce the negative effects of climate change on the northern species, relatively large areas of continuous habitats in a connected reserve network should be preserved.     

Will future climate change threaten a range restricted endemic species, the quokka (Setonix brachyurus), in south west Australia?

Range-restricted species, such as regional endemics, possess traits that may make them particularly vulnerable to environmental change. The quokka, Setonix brachyurus, is a small macropod, endemic to south-western Australia and two adjacent islands. Climatic factors appear to play a role in defining the distribution of this species. Mainland populations are historically restricted to areas with an annual average rainfall in excess of 700 mm and their current distribution is almost completely confined within the 1000 mm rainfall isohyet. As such, the predicted increasing aridity of south-western Australia due to climate change is likely to threaten the continued persistence of the quokka on the mainland. To examine this possibility, we modelled the distribution of the quokka with Maxent using records of occurrence and a combination of historical climate (1961-1990) and habitat variables. Future projections of this distribution were then examined assuming two simple dispersal scenarios (zero and full migration) and three climate-change scenarios of increasing severity for 2030, 2050 and 2070. The predictive performance of the distribution model generated under historical climate conditions was high (AUC > 0.8), with annual precipitation contributing the most information to the model. Except for the low-severity climate-change scenario under the full dispersal assumption, the future projected distribution of quokka was shown to contract over time. The extent of range contraction tended to increase with the severity of the climate-change scenario, with the species predicted to lose almost all range by the year 2070 under the most extreme climate-change scenario. The results indicate the importance of identifying potential refuges for the quokka (i.e. areas where the species is predicted to persist) and defining management strategies to protect these areas from threatening processes.     

郊野公园乡土景观资源应用策略研究——以榆林市榆溪河郊野森林公园为例

郊野公园是城市边缘区景观系统的重要组成。在城乡融合发展的趋势下,乡土景观资源的保护与应用对于郊野公园建设具有重要价值与意义。研究结合榆林市榆溪河郊野公园案例,以“生态、生活、生产”三生共融为目标,提出乡土景观资源在郊野公园中的保护、延续与再生应用策略,为保障城市生态安全格局、满足现代城市人群游憩需求、展现地域乡土特色、促进周边区域发展、构建符合现代城乡可持续发展的景观提供参考。     

国外森林权属制度改革现状与路径

近30年来,世界许多国家开展了森林及林地权属制度改革。改革的主要方向是将森林/林木的所有权/经营管理权下放给政府之外的利益主体,包括家庭、企业和社区。这种改革涉及到森林管理权和经营利用权的下放及森林所有权私有化等复杂多样的产权形式。文中以联合国粮农组织发布的相关报告及国外林权改革相关文献资料为主要素材,选择德国、日本、新西兰、欧洲部分转型国家及独联体国家等诸多国家的改革案例,对国外林权制度改革类型进行梳理,以总结国外林权制度改革的现状、路径和趋势等,为我国林权制度改革提供借鉴。