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31.
In the course of floristic studies in suburban forests near the city of Ivanovo, 206 species of vascular plants have been recorded, including 39 invasive species (18.9%). Information on specific features of distribution and activity of introduced species growing feral and accidental weeds in different forest types is presented. The most aggressive species are distinguished. Factors responsible for the invasion of alien species to forest cenoses and main tendencies in their dynamics are discussed.  相似文献   
32.
The switch from hunting wild meat for home consumption to supplying more lucrative city markets in Amazonia can adversely affect some game species. Despite this, information on the amounts of wild meat eaten in Amazonian cities is still limited. We estimated wild meat consumption rates in 5 cities in the State of Amazonas in Brazil through 1046 door-to-door household interviews conducted from 2004 to 2012. With these data, we modeled the relationship between wild meat use and a selection of socioeconomic indices. We then scaled up our model to determine the amounts of wild meat likely to be consumed annually in the 62 urban centers in central Amazonia. A total of 80.3% of all interviewees reported consuming wild meat during an average of 29.3 (CI 11.6) days per year. Most wild meat was reported as bought in local markets (80.1%) or hunted by a family member (14.9%). Twenty-one taxa were cited as consumed, mostly mammals (71.6%), followed by reptiles (23.2%) and then birds (5.2%). The declared frequency of wild meat consumption was positively correlated with the proportion of rural population as well as with the per capita gross domestic product of the municipality (administrative divisions) where the cities were seated. We estimated that as much as 10,691 t of wild meat might be consumed annually in the 62 urban centers within central Amazonia, the equivalent of 6.49 kg per person per year. In monetary terms, this amounts to US$21.72 per person per year or US$35.1 million overall, the latter figure is comparable to fish and timber production in the region. Given this magnitude of wild meat trade in central Amazonia, it is fundamental to integrate this activity into the formal economy and actively develop policies that allow the trade of more resilient taxa and restrict trade in species sensitive to hunting.  相似文献   
33.
Inhibition of Amazon Deforestation and Fire by Parks and Indigenous Lands   总被引:10,自引:0,他引:10  
Abstract:  Conservation scientists generally agree that many types of protected areas will be needed to protect tropical forests. But little is known of the comparative performance of inhabited and uninhabited reserves in slowing the most extreme form of forest disturbance: conversion to agriculture. We used satellite-based maps of land cover and fire occurrence in the Brazilian Amazon to compare the performance of large (>10,000 ha) uninhabited (parks) and inhabited (indigenous lands, extractive reserves, and national forests) reserves. Reserves significantly reduced both deforestation and fire. Deforestation was 1.7 (extractive reserves) to 20 (parks) times higher along the outside versus the inside of the reserve perimeters and fire occurrence was 4 (indigenous lands) to 9 (national forests) times higher. No strong difference in the inhibition of deforestation ( p = 0.11) or fire ( p = 0.34) was found between parks and indigenous lands. However, uninhabited reserves tended to be located away from areas of high deforestation and burning rates. In contrast, indigenous lands were often created in response to frontier expansion, and many prevented deforestation completely despite high rates of deforestation along their boundaries. The inhibitory effect of indigenous lands on deforestation was strong after centuries of contact with the national society and was not correlated with indigenous population density. Indigenous lands occupy one-fifth of the Brazilian Amazon—five times the area under protection in parks—and are currently the most important barrier to Amazon deforestation. As the protected-area network expands from 36% to 41% of the Brazilian Amazon over the coming years, the greatest challenge will be successful reserve implementation in high-risk areas of frontier expansion as indigenous lands are strengthened. This success will depend on a broad base of political support.  相似文献   
34.
Analyzing and predicting the development of foliar nutrient concentrations are important and challenging tasks in environmental monitoring. This article presents how linear sparse regression models can be used to represent the relations between different foliar nutrient concentration measurements of coniferous trees in consecutive years. In the experiments the models proved to be capable of providing relatively good and reliable predictions of the development of foliage with a considerably small number of regressors. Two methods for estimating sparse models were compared to more conventional linear regression models. Differences in the prediction accuracies between the sparse and full models were minor, but the sparse models were found to highlight important dependencies between the nutrient measurements better than the other regression models. The use of sparse models is, therefore, advantageous in the analysis and interpretation of the development of foliar nutrient concentrations.  相似文献   
35.
ABSTRACT: Dendrochronology analyses of point bar complexes were used to quantify the effects of riparian forests on local lateral migration of bends in seven streams in the glacial till plains of north central Missouri. Stream bends were paired with similar bank height, midchannel radius of curvature, soil composition, and watershed size. In each pair, one concave bank was forested and one was unforested. Stream bends with unforested concave banks had an average local migration rate three times greater than stream bends that had forested concave banks.  相似文献   
36.
基于过去20a全球森林植被中汞循环过程的相关研究,本文通过荟萃分析法阐明全球主要森林类型中植被汞分布特征及其影响因素.结果表明,汞在植被中浓度排序特征(以中值计)依次为凋落物(38.9ng/g)>叶片(24.1ng/g)>树根(18.5ng/g)>树皮(13.2ng/g)>树枝(12.0ng/g)>树干(3.1ng/g...  相似文献   
37.
This study aims to identify services provided by forest ecosystems based on locals’ perceptions in the northern part of Jordan. By better understanding preferences of locals and by understanding why they value certain services more heavily, policy-makers and planning managers can make more effective decisions regarding development and conservation. Three hundred respondents were interviewed in order to collect information about forest ecosystem services (ES). Data collection was conducted using a structured questionnaire regarding ES provided by three forest types situated in northern Jordan. ES trade-offs and socio-ecological bundles were identified by analyzing respondents’ socioeconomic demographics and preferences of forest ES through multivariate canonical corresponding analysis (CCA). The statistical analysis indicated that the socioeconomic factors and forest type have an effect on social preferences toward ES. Results displayed a clear trade-off between provisioning services and regulating and cultural services. CCA demonstrated that 73% of the variation in ES value is explained by social factors (i.e. education level, income level, and gender), while 26% of perception variation was attributable to categories of ES supplied by each forest ecosystem. These findings imply that involving people in the place-specific management of public forests using the ES approach gives managers a clearer understanding of the benefits people recognize and value, as well as those they either are not aware of or do not value. Such information is useful in forest management and in public outreach. Although direct policy applications are limited by the research’s nature, the paper provides a starting point for incorporating forest users’ voices into policy discussions and management design.  相似文献   
38.
邓慧平 《生态环境》2012,21(4):601-605
为了揭示气温变化对西南山区流域森林水文效应的影响,用生物物理/动态植被模型SSiB4/TRIFFID与流域地形指数水文模型TOPMODEL的耦合模型SSiB4T/TRIFFID模拟了西南山区长江上游梭磨河流域森林水文效应对气温变化的响应,分析了气温变化对植被不同演替阶段的流域总径流和总蒸发以及冠层截流蒸发、植被蒸腾和土壤蒸发的影响。结果表明,(1)梭磨河流域森林(常绿针叶林)蒸腾与草和灌木差异小,森林蒸腾潜热比草和灌木仅高1~4 W.m-2,森林冠层截留蒸发高于草和灌木,但土壤蒸发明显低于草和灌木覆盖,森林覆盖流域总蒸发低于草和灌木覆盖甚至低于裸土蒸发,因此增加了流域总径流量,但森林增加径流的作用随土壤蒸发的减小而减小。(2)气温减小1℃将通过减小森林冠层截留蒸发和蒸腾而使森林增加流域总径流量的作用增加;相反,气温增加将增加森林冠层截留蒸发和蒸腾而使森林增加总径流量的作用减小。(3)当温度增加4℃,由于森林总蒸发较草和灌木明显增加,对于较高的土壤蒸发,森林增加总径流量的作用已不明显;对于较低的土壤蒸发,森林减小了流域总径流量。  相似文献   
39.
This article focuses on modelling above and below-ground mass loss and nitrogen (N) dynamics based on the wooden dowels (Gonystylus bancanus [Miq.] Kurz) of the decadal Long-term Intersite Decomposition Experiment (LIDET) data. These dowels were placed at 27 locations across North and Central America, involving tropical, temperate and boreal forests, grasslands, wetlands and the tundra. The dowel, inserted vertically into the soil with one half remaining exposed to the air, revealed fast mass and N losses under warm to humid conditions, and slow losses under wet as well as cold to dry conditions. The model formulation, referred to as the Wood Decomposition Model, or WDM, related these losses to (i) mean annual precipitation, mean monthly January and July air temperatures, and (ii) mean annual actual evapotranspiration (AET) at each location. The resulting calibrations conformed well to the time-in-field averages for mass remaining by location: R2 = 0.83 and 0.90 for the lower and upper parts, respectively. These values dropped, respectively, to 0.41 and 0.55 for the N concentrations, and to 0.28 and 0.43 for N remaining. These reductions likely refer to error propagation and to as yet unresolved variations in N transference into and out of the wood specific to each individual dowel location. Recalibrating the model parameters by ecosystem type reduced the R2 values for actual versus best-fitted mass loss by about 0.15. Doing the same without location- or ecosystem-specific adjustments reduced the R2 values further, by about 0.3.  相似文献   
40.
国有自然资源资产管理体制改革的建议与思考   总被引:1,自引:3,他引:1       下载免费PDF全文
自然资源产权管理和专业监管的分立可充分发挥市场作用,进一步促进简政放权,实现对山水林田湖草的综合管理,克服监管盲点,提升综合保护绩效,促进绿水青山转化为金山银山。设立专门机构开展自然资源资产管理,《生态文明体制改革总体方案》等规定了改革依据;自然资源统一确权登记试点取得积极进展,奠定了工作基础;与自然资源资产负债表、绿色GDP核算、生态文明建设目标评价考核等结合起来,促进改革的系统化和连贯化;建议在国家和省、市成立三级国有自然资源资产管理机构,在部分区域和流域派驻机构。为保障改革的实施,需界定国有自然资源资产的范围及所有权、监管权的角色和权限;改革生态补偿、排污权有偿使用、资源有偿利用等制度;明晰流域与属地的权力(利)关系;明确自然资源资产管理职责和生态环保党政同责的关系;重构环境保护税、资源税和自然资源资产使用费的关系;规定自然资源资产管理的原则、体制、制度和责任;建立自然资源资产清单、权利清单和管理信息平台;厘清各方权利边界和监管边界,建立评价考核和奖惩机制。  相似文献   
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