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81.
Results of stationary studies on the spatial location of sables (Martes zibellinaL.) belonging to different age and sex groups are summarized. Mapping the sites where 388 animals were taken, it was found that young animals tended to live near floodplains; adult animals, on watersheds. Analysis of sables taken by commercial hunters (n= 1833) made it possible to estimate the age composition and the degree and spatial distribution of the hunting pressure on sable populations in three areas of the Ob region. The spatial separation of young and reproductive animals is interpreted as a group adaptive response to the specific distribution pattern of different habitats typical of this species and to the pattern of animal elimination. It is proposed to use the specific pattern of animal distribution for maintaining the size of the population that is subject to hunting. Specifically, reserve (reproductive) territories should be organized in watershed areas. 相似文献
82.
Anton McLachlan Martin Fisher Harib Nasser Al-Habsi Salah Salim Al-Shukairi Ahmed Mohammed Al-Habsi 《Journal of Coastal Conservation》1998,4(2):181-190
The benthic macrofauna and physical features of 10 sandy beaches along the coast of Oman were surveyed quantitatively. This is a mesotidal regime mostly subject to low to moderate wave energy but more exposed in the south. Five northern beaches are tide-dominated, with low wave energy, and their profiles consist of a berm, a steep, swash-dominated upper shore and a broad tide-dominated terrace from mid-shore downwards. They are composed of moderately sorted fine to medium sands. Southern beaches experience greater wave energy, particularly during the summer southwest monsoon, and exhibit smoother, concave profiles with fine, fairly well sorted carbonate sand. 58 species and species groups were recorded, with crustanceans, polychaetes and molluscs dominant. In general species richness was high, at least 19–25 species per beach, but dry biomass moderate to low at 26–90g/m shoreline, with one high value of 450g/m. Total abundance was moderate at 3–73×103 organisms/m of beach. Some zonation was evident with ocypodid crabs andTylos in the supralittoral, cirolanid isopods on the upper shore and a variety of species on the lower shore. The coast of Oman appears to constitute a single zoogeographic region, but with some regional differentiation between north and south due to varying physical conditions. Thus, OmanÕs beaches are characterized by tide-dominated morphodynamics and exceptionally high species richness. 相似文献
83.
Fresh water, a fundamental element of all estuarine ecosystems, is South Africa’s most limited natural resource. Recent projections
indicate that by the year 2020 the country will be utilizing all its exploitable freshwater sources. Steeply increasing demands
by a rapidly growing population on this limited commodity have already resulted in a severe reduction of water supplies to
natural users such as estuaries — this trend is predicted to increase in the future. Concurrent with excessive water abstraction,
poor land husbandry (e.g. soil erosion) in many catchment basins and pollution (e.g. salinization) in return flows have led
to a serious deterioration in water quality. In contrast, a review of estuarine responses to varying flow regimes stresses
the strong dependence of local systems on riverine fresh water inputs of adequate quantity and quality. Freshwater dependence
is i.a. expressed in: flooding events that scour accumulated sediments, riverine nutrient input to drive estuarine phyto-
and zooplankton production, axial salinity gradients that increase habitat and species diversity, and maintenance of open
tidal inlets that prevent salinity and temperature extremes and facilitate larval exchange, fish migrations and tidal flushing
of salt marshes. Thus, estuarine conservation will have to encompass management of rivers and watersheds and play an increasingly
political role in decision processes concerning water allocations among ‘human’ and ‘natural’ users. 相似文献
84.
The size and complexity of industrial plants, along with the characteristics of the products used, require a study, analysis and control of the existing risks in every industrial process.In this paper, a methodology for risk assessment in industrial plants, based on the combination of risks identification through the Hazard and Operability (HAZOP) analysis and the risks evaluation through linguistic variables and fuzzy numbers is applied to a case study consisting on a compound feed plant located in the town of Silla (Valencia, Spain).The results from this study show that the main risk in the compound feed production process is the formation of explosive atmospheres (ATEX). Therefore, the corrective measures will focus on reducing the concentration of dust in the atmosphere and eliminating the possible sources of ignition, such as electrostatic discharges or sparks during the different phases of the process (the grinding, the transport of the raw materials, etc.) 相似文献
85.
The Evolution of the Environmental Quality Concept: From the US EPA Red Book to the European Water Framework Directive 总被引:1,自引:0,他引:1
Vighi M Finizio A Villa S 《Environmental science and pollution research international》2006,13(1):9-14
- DOI: http://dx.doi.org/10.1065/espr2006.01.003
Background Water Quality Criteria were firstly defined in the 1970s by the EPA in the USA and the EIFAC in Europe, recognizing the need
for protecting water quality in order to allow the use of water resources by man. In the 1990s, the European Commission emphasized
the importance of safeguarding structure and function of biologic communities. These approaches were chemically-based. The
European Water Framework Directive (WFD) substantially changes the concept of Water Quality, by assuming that a water body
needs to be protected as an environmental good and not as a resource to be exploited. In this frame, the biological-ecological
quality assumes a prevailing role.
Main Features The Water Quality concept introduced by the WFD is a challenge for environmental sciences. Reference conditions should be
defined for different typologies of water bodies and for different European ecoregions. Suitable indicators should be developed
in order to quantify ecological status and to define what a 'good' ecological status is. Procedures should be developed for
correlating the deviation from a good ecological to the effects of multiple stressors on function and structure of the ecosystem.
The protection of biodiversity becomes a key objective. In this frame, the traditional procedures for ecotoxicological risk
assessment, mainly based on laboratory testing, should be overcome by more site-specific approaches, taking into account the
characteristics and the homeostatic capabilities of natural communities. In the paper an overview of the present knowledge
and of the new trends in ecotoxicology to get these objectives will be given. A procedure is suggested based on the concept
of Species Sensitivity Distribution (SSD).
Recommendations and Perspective . The need for more site-specific and ecologically-oriented approaches in ecotoxicology is strongly recommended. The development
of new tools for implementing the concept of 'Stress Ecology' has been recently proposed by van Straalen (2003). In the same
time, more 'cological realism'is needed in practically applicable procedures for regulatory purposes. 相似文献
86.
Comparison of vegetation conditions along two backcountry trails in Mount Robson Provincial Park, British Columbia (Canada) 总被引:4,自引:0,他引:4
Vegetation conditions, i.e., plant cover, species richness, and the presence of exotic species, are compared along a high-use trail (Berg Lake Trail--BLT) and a low use trail (Mt. Fitzwilliam Trail--FWT) in Canada's Mt. Robson Provincial Park. We established 71 paired quadrats (1 m x 1 m), and assessed the amount of vegetation cover and species richness by four main lifeforms, i.e., woody species, herbaceous species, ferns, and moss, lichen and fungi. The following hypotheses were tested: (1) differences exist between control and trailside quadrats in vegetation cover, species richness and floristic diversity, and (2) differences exist between the high and low-use trails in the above-mentioned three parameters. Results show that for the majority of variables the differences between the control and trailside quadrats are statistically not significant. Variables showing significant differences are relative vegetation cover (for BLT only), exposed soil (BLT and FWT), herbaceous cover (FWT), moss, lichen and fungi cover (BLT), overall species richness (BLT), and herbaceous species richness (BLT). Ruderal and exotic species are present but only on trailside quadrats of the high-use trail. Results indicate that the Park administration's strategy to disperse use in the Mt. Robson Provincial Park should be examined critically, and some guidelines for acceptability of changes should be developed. 相似文献
87.
辽东湾北部双台子河口的斑海豹 总被引:6,自引:1,他引:6
2003年3月至4月及2004年3月至5月。对辽东湾北部双台子河口附近的斑海豹栖息地及斑海豹资源进行了调查。斑海豹数量和行为的观察采用海上目视直接观察及照相计数方法;栖息地的环境调查为现场结合社会调查。结果发现:斑海豹的栖息地十年来位置未改变,仍在距人海口10km处的一段河岸,但其生态环境正遭到破坏。斑海豹在该栖息地的分布时间从3月初辽东湾冰融起至5月中旬;高峰期在3月底至4月中旬之间;4月中旬斑海豹开始离开,比十年前提早半个月左右;5月中旬以后。斑海豹基本上全部离开此处。另外,斑海豹的个体数:2003年为105头。而2004年则为40头。其数量年变化较大。 相似文献
88.
高清平 《中国安全科学学报》2011,21(3)
为解决不确定环境下的风险分析问题,针对危险货物运输中风险参数具有不确定性、随机性和模糊性的特点,建立基于概率测度-可能性测度转换原则和模糊逻辑的危险货物运输风险分析方法。首先对具有模糊性的参数直接建立模糊数,对具有随机性的参数建立随机数;接着依据概率测度向可能性测度转换的最优原则,将随机数转换为模糊数;然后根据模糊运算法则进行风险计算和分析。最后通过一个算例验证了模型和算法的有效性。结果表明,提出的方法能处理随机和模糊环境下的风险分析问题,能为风险分析尽可能多地保留不确定性信息,尽可能少地丢失有用信息。 相似文献
89.
Understanding how different audience groups perceive wildlife is crucial for the promotion of biodiversity conservation, especially given the key role of flagship species in conservation campaigns. Although the heterogeneity in preferences reinforces the need for campaigns tailored to specific target audiences, many conservation education and awareness campaigns still claim to target the “general public”. Audiences can be segmented according to social, economic, and cultural criteria across which species perceptions are known to vary. Different studies have investigated the preferences of different groups towards certain wildlife species, but these are largely confined to a single conservation stakeholder group, such as tourists, local communities, or potential donors in western countries. In this study, we seek to determine from a multi-stakeholder perspective, audience characteristics that influence perceptions towards wildlife at Valparai, a fragmented plateau in the Western Ghats region of the Western Ghats-Sri Lanka Hotspot. We found that stakeholder group membership was the most important characteristic followed by gender. While some characteristics had a wide-scale effect others were restricted to a few species. Our results emphasize the need to design conservation campaigns with specific audiences in mind, instead of the very often referred to “general public”. 相似文献
90.
Coastal development has severely affected habitats and biodiversity during the last century, but quantitative estimates of the impacts are usually lacking. We utilize predictive habitat modeling and mapping of human pressures to estimate the cumulative long-term effects of coastal development in relation to fish habitats. Based on aerial photographs since the 1960s, shoreline development rates were estimated in the Stockholm archipelago in the Baltic Sea. By combining shoreline development rates with spatial predictions of fish reproduction habitats, we estimated annual habitat degradation rates for three of the most common coastal fish species, northern pike (Esox lucius), Eurasian perch (Perca fluviatilis) and roach (Rutilus rutilus). The results showed that shoreline constructions were concentrated to the reproduction habitats of these species. The estimated degradation rates, where a degraded habitat was defined as having ≥3 constructions per 100 m shoreline, were on average 0.5 % of available habitats per year and about 1 % in areas close to larger population centers. Approximately 40 % of available habitats were already degraded in 2005. These results provide an example of how many small construction projects over time may have a vast impact on coastal fish populations.