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21.
Abstract: We examined how differences in local forest‐management institutions relate to disparate anthropogenic forest disturbance and forest conditions among three neighboring montane forests in Tanzania under centralized, comanaged, or communal management. Institutional differences have been shaped by decentralization reforms. We conducted semistructured interviews with members of forest management committees, local government, and village households and measured anthropogenic disturbance, tree structure, and species composition in forest plots. We assessed differences in governance system components of local institutions, including land tenure, decision‐making autonomy by forest users, and official and de facto processes of rule formation, monitoring, and enforcement among the three management strategies. We also assessed differences in frequencies of prohibited logging and subsistence pole cutting, and measures of forest condition. An adjacent research forest served as an ecological reference for comparison of forest conditions. Governance was similar for comanaged and centralized management, whereas communal managers had greater tenure security and decision‐making autonomy over the use and management of their forest. There was significantly less illegal logging in the communal forest, but subsistence pole cutting was common across all management strategies. The comanaged forest was most disturbed by recent logging and pole cutting, as were peripheral areas of the larger centralized forest. This manifested in more degraded indicators of forest conditions (lower mean tree size, basal area, density of trees ≥ 90 cm dbh, and aboveground biomass and higher overall stem density). Greater tenure security and institutional autonomy of the communal strategy contributed to more effective management, less illegal logging, and maintenance of good forest conditions, but generating livelihood benefits was a challenge for both decentralized strategies. Our results underscore the importance of well‐designed institutional arrangements in forest management and illustrate mechanisms for improved forest governance and conservation in the context of Tanzanian decentralization reforms. 相似文献
22.
Dynamics of Bacterial Abundance,Biomass, Activity,and Community Composition in the Oligotrophic Traunsee and the Traun River (Austria) 总被引:1,自引:0,他引:1
Klammer Susanne Posch Thomas Sonntag Bettina Griebler Christian Mindl Birgit Psenner Roland 《Water, Air, & Soil Pollution: Focus》2002,2(4):137-163
The holomictic Traunsee is the deepest and second largest lakein Austria. The special characteristic of this ecosystem isthe fact that local salt and soda industries presumably alterthe lake by the discharge of waste materials. Since thebeginning of the 20th century salt and soda works areannually releasing up to 50,000 tons of solid wastes and up to150,000 tons of chloride into Traunsee. To assess potentialeffects of these anthropogenic impacts on the bacterioplanktonthree sampling sites, influenced as well as not influenced bythe industrial discharge, were chosen for comparison andsampled monthly from November 1997 to October 1998. Bacterialabundance ranged between 0.4 to 3.0 × 106 cells ml-1 with decreasing numbers along the depth profile. Theproportion of actively respiring bacteria, i.e. INT [2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride]reducing cells, never exceeded 10% of DAPI (4',6'-diamidino-2-phenylindole) stained cells. Fluorescence in situ hybridization (FISH) was used to examine the seasonal and spatial distribution of dominant phylogenetic groups of thebacterioplankton. Up to 84% of bacteria detected with DAPIcould be detected via FISH applying the universal bacterialprobe EUB338. Percentages of alpha- and beta-Proteobacteriaand members of the Cytophaga-Flavobacterium cluster did notexceed 60% of DAPI-stained cells.Beta-Proteobacteriaappeared to be the most abundant group, not only in Traunsee butalso in two reference lakes, Attersee and Hallstättersee. No significant differences in any of the bacterial parameters couldbe detected between the three sampling sites and all measurementswere found in the range reported for oligotrophic lakes. The highdischarge of the Traun River, resulting in a lake water renewaltime of only one year, may diminish possible effects of industrial waste discharge in the pelagic zone. 相似文献
23.
Trends in plant cover synanthropization along a plain-foothills-mountains gradient have been revealed in the reserve. Characteristics of plant communities in anthropogenically disturbed habitats, centers of concentration of anthropophytes and apophytes, and pathways of their migration are described. 相似文献
24.
A. P. Galanina 《Russian Journal of Ecology》2008,39(6):418-424
The population density and relative abundance of some bird species reach the highest values in the communities of habitats with a high degree of anthropogenic transformation. The species diversity of birds shows an inverse correlation with the index of anthropogenic impact (in grades) calculated with regard to a number of parameters. Relevant correlations change periodically, with the correlation coefficient reaching the highest values in the nesting period and decreasing to a minimum during the flight period. 相似文献
25.
26.
Ramiz M. Mamedov Boyukagha N. Mustafayev 《Environment, Development and Sustainability》2007,9(2):131-142
In order to determine the potential for sustainable regional development of the Caspian coastal zone, a study was made for
the Khachmaz–Absheron zone of Azerbaijan. An evaluation was performed to assess the anthropogenic load on landscapes. Using
the 8-point scale offered by Isachenko [2001, Ecological Geography of Russia, Saint Petersburg University Press, Saint Petersburg]
for the indicators of agricultural, industrial, urban and integral anthropogenic loads, we did a preliminary ranking of the
provinces in the Khachmaz–Absheron zone of Azerbaijan for the each indicator taken separately. Vital statistics were used
as a supplementary indicator of environmental conditions in the region. By comparing the data for provinces with each other
and the data on Azerbaijan average, we have classified the provinces into 4 groups according to specific combinations of the
indicators. Each group of provinces has distinctive environmental conditions and features for sustainable development. The
classification makes it possible to develop certain recommendations for the regional sustainable development. Measures to
be implemented within the Azerbaijan State Program on Social and Economic Development of Regions are also discussed. In the
Khachmaz province, production of ecologically pure products is highly recommended. Special attention should be given to the
development of tourism and recreational institutions in the Khachmaz, Khizi and Devechi provinces. Recommendations for these
provinces include further development of industry on the basis of modern safe technologies. The irrigation and drainage networks
should be reconstructed. The reconstruction will make it possible to reduce water loss and to increase the productivity of
agriculture. In the Absheron province, Baku and Sumgait cities environmental systems are overloaded, and so the works at highly
polluting enterprises must be stopped, the enterprises have to be re-equipped (old filters must be changed first of all) or
relocated from the area (a decrease of environmental risk should be in the focus of attention). For improving of air quality,
green areas should increase. There is a need to reduce urban traffic density and to reconstruct highways. Use of old vehicles
must be forbidden or restricted, and transition to environmentally friendly fuel should be supported in every way possible.
It is necessary to bring the waste management system and sanitary landfills up to international standards, and to improve
the water supply and sewerage systems. 相似文献
27.
以我国114个城市冬季(2013年12月-2014年2月)公布的PM25数据为基础,结合其他相关数据,运用空间自相关分析、克里格插值法和逐步回归分析法,研究我国冬季PM2.5浓度空间分布差异及其影响因素.结果显示,研究期间PM2.5在空间分布上具有高值集聚、低值集聚和高值邻域的低值集聚的变化特征,全局自相关系数Moran's I为0.27.PM2.5浓度分布由北到南、从内陆到沿海具有先升高后逐渐降低的变化趋势,高浓度区域主要集中在华北平原、长江中下游平原和陕西关中平原等地区,这些区域的冬季PM2.5平均质量浓度都达到150 μg·m-3以上,最高达250 μg·m-3.多因子逐步回归分析结果表明,人为活动对我国高浓度PM25(>150μg·m-3)分布影响显著,对低浓度PM2.5(≤75μg·m-3)分布影响不显著.市辖区人口密度和第二产业GDP是显著影响我国高浓度PM2.5分布的主要人为影响因子.市辖区建成区面积、全市年末总人口和市辖区道路面积等是影响我国城市间PM2.5浓度分布差异的主要人为影响因子. 相似文献
28.
在低NOx浓度条件下开展甲苯和异戊二烯复合体系的烟雾箱模拟实验,使用高时间分辨率的在线质子转移反应飞行时间质谱(PTR-TOF-MS)实时监测混合体系中反应物与产物的浓度变化情况,探究人为源与天然源交汇过程中, 自然源挥发性有机物 (BVOCs)对人为挥发性有机物(AVOCs)化学降解的影响.结果表明,异戊二烯与甲苯竞争OH自由基,从而抑制了甲苯的化学降解,该竞争反应开始得越早,抑制效果越显著.研究还发现异戊二烯会增强甲苯RO2降解途径产物的产量,生成更多1,4不饱和-二羰基化合物(如丁烯二醛和甲基丁烯二醛)与二羰基化合物(如乙二醛和甲基乙二醛),其中甲基丁烯二醛增量最高可达38.6%.此外,异戊二烯快速氧化生成的RO2自由基碳数更少,可能与甲苯氧化生成的RO2自由基发生了快速的交叉反应,有利于甲苯RO自由基的生成及裂解,最终导致甲苯RO2途径裂解产物的增加. 相似文献
29.
30.
V. N. Vtorova 《Russian Journal of Ecology》2004,35(5):296-302
Variation in the content of N, P, K, Ca, Mg, Na, Cu, Zn, Mn, and Fe has been analyzed in the needles of 19 spruce species growing in the natural and urbanized ecosystems of Siberia and Central Asia. The results have shown that similarity in the content of biophilic elements in one-year-old needles of different species is conditioned by biochemical processes, which confirms the status of these species as passive bioindicators of environmental quality. The contents of trace elements in perennial needles, except color variations of chlorophyll, deserve further study as prospective indicators of environmental quality. 相似文献