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771.
SALLY E. M. FRASER† ALISON E. BERESFORD† JENNIFER PETERS† JOHN W. REDHEAD† ALASTAIR J. WELCH† PETER J. MAYHEW† CALVIN DYTHAM† 《Conservation biology》2009,23(1):142-150
Abstract: Selecting suitable nature reserves is a continuing challenge in conservation, particularly for target groups that are time-consuming to survey, species rich, and extinction prone. One such group is the parasitoid Hymenoptera, which have been excluded from conservation planning. If basic characteristics of habitats or vegetation could be used as reliable surrogates of specific target taxa, this would greatly facilitate appropriate reserve selection. We identified a range of potential habitat indicators of the species richness of pimpline parasitoid communities (Hymenoptera: Ichneumonidae: Pimplinae, Diacritinae, Poemeniinae) and tested their efficiency at capturing the observed diversity in a group of small woodlands in the agricultural landscape of the Vale of York (United Kingdom). Eight of the 18 vegetation-based reserve-selection strategies were significantly better at parasitoid species inclusion than random selection of areas. The best strategy maximized richness of tree species over the entire reserve network through complementarity. This strategy omitted only 2–3 species more (out of 38 captured in the landscape as a whole) than selections derived from the parasitoid survey data. In general, strategies worked equally well at capturing species richness and rarity. Our results suggest that vegetation data as a surrogate for species richness could prove an informative tool in parasitoid conservation, but further work is needed to test how broadly applicable these indicators may be. 相似文献
772.
773.
Decadal changes in a NW Mediterranean Sea food web in relation to fishing exploitation 总被引:1,自引:0,他引:1
We analysed changes in the ecological roles of species, trophic structure and ecosystem functioning using four standardized mass-balance models of the South Catalan Sea (North-western Mediterranean). Models represented the ecosystem during the late 1970s, mid 1990s, early 2000s, and a simulated no-fishing scenario. The underlying hypothesis was that ecosystem models should quantitatively capture the increasing exploitation in the ecosystem from the 1970s to 2000s, as well as differences between the exploited and non-exploited scenarios. Biomass showed a general decrease, while there was an increase in biomass at lower trophic levels (TL) from the 1970s to 2000s. The efficiency of energy transfer (TE) from lower to higher TLs significantly increased with time. The ecosystem during the 1990s showed higher biomass and flows than during the 1970s and 2000s due to an increase in small pelagic fish biomass (especially sardines). Exploited food webs also showed similarities in terms of general structure and functioning due to high intensity of fishing already in the 1970s. This intensity was highlighted with low trophic levels in the catch, high consumption of production by fisheries, medium to high primary production required to sustain the catches and high losses in secondary production due to fishing. Significant differences on ecosystem structure and functioning were highlighted between the exploited and no-fishing scenarios. Biomass of higher TLs increased under the no-fishing scenario and the mean trophic level of the community and the fish/invertebrate biomass ratios were substantially lower in exploited food webs. The efficiency of energy transfer (TE) from lower to higher TLs was lower under the no-fishing scenario, and it showed a continuous decrease with increasing TL. Marine mammals, large hake, anglerfish and large pelagic fish were identified as keystone species of the ecosystem when there was no fishing, while their ecological importance notably decreased under the exploited periods. On the contrary, the importance of small-sized organisms such as benthic invertebrates and small pelagic fish was higher in exploited food webs. 相似文献
774.
775.
The disposal of sewage sludge from municipal waste water treatment plants is suffering from raising costs.The gasification is an alternative way of treatment, which can reduce the amount of solid residues that must be disposed from a water treatment plant. The produced gas can be used very flexible to produce electrical energy, to burn it very cleanly or to use it for upgrading.The gasification in the fluidised bed and the gas cleaning with the granular bed filter has shown successful operation. A demonstration plant in Balingen was set up in 2002 and rebuilt to a larger throughput in 2010. As a next step a demonstration plant was built in Mannheim and is now at the end of the commissioning phase. Nowadays the product gas is blended with biogas from sludge fermentation and utilized in a gas engine or combustion chamber to produce heat. In the future the process control for a maximized efficiency and the removal of organic and inorganic impurities in the gas will be further improved. 相似文献
776.
Johann Baumgärtner Josef Hartmann 《Journal of Agricultural and Environmental Ethics》2001,14(1):67-83
The paper describes the design and implementation of a plant biodiversity conservation program that was developed under funding and time constraints for diverse ecological, social, and institutional environments. The biodiversity program for alpine meadows and pastures located in the Swiss Canton of the Grisons is used as an example. The design of the sustainable program relied on existing legislation, accounted for limited ecological knowledge and expertise, and considered biodiversity as a common-pool resource. The trend to intensified cultivation of restricted areas required fast action, while the sustainability of the program design had to take into account institutional diversity. Fifteen habitats and plant communities worth conserving were known, and 57 plant species were identified as indicator species for establishing an inventory and for monitoring purposes. A small subset of 16 well known plant species was presented to the farming communities. They were invited to notify the areas in which they observed the presence of these plants. In different regions of the Canton a total number of 39 paraecologists were trained to inspect the areas notified by farmers and to recommend possible incorporation into the Cantonal inventory. This was done once the farmers signed a contract in which they agreed to follow adequate management practices. The farmers received subsidies to compensate for their losses. Communal authorities controlled the fertilizer input and cutting dates, while the paraecologists were trained to monitor plant biodiversity. The program started in 1992 and the initial phase of the inventory was terminated in 1996. At the beginning of 1996, an inventory of 2617.19 ha, most of which are meadows, was taken and managed according to the rules specified in the contract. The program was considered successful because (i) of the size of the area in the inventory, (ii) about 30%of the farmers participated, and (iii) farmers started cultivating previously abandoned farmland. 相似文献
777.
分别采用水解 -二段生物接触氧化以及二段生物接触氧化两种工艺 ,通过接种高效蔗糖降解菌对蔗糖厂洗布水的生化处理进行试验研究 ,结果表明 :填料采用煤渣较好 ;加适量的氮源和磷源能提高生化处理效果 ;两种工艺处理都能使废水达标排放 ,但从经济角度考虑认为水解 -二段接触氧化工艺较优。 相似文献
778.
N. F. Chernousova 《Russian Journal of Ecology》2001,32(2):122-125
The long-term population dynamics of rodent communities in park forests of Yekaterinburg was studied. The results showed that deep population depressions occurring in natural communities are not characteristic of the urban communities. In the urban environment, the density of rodents is always maintained at a relatively high level due to the appearance of species that are atypical for the natural communities. This fact deserves attention in view of the increasing risk of tick-borne encephalitis (TBE) in the region, as a high rodent abundance may provide for the maintenance of a stable TBE focus in the city. 相似文献
779.
Russian Journal of Ecology - 相似文献
780.
香港汀角红树植物、沉积物及双壳类动物重金属含量 总被引:14,自引:0,他引:14
汀角有香港面积最大的硬底质红树林,作者调查了该红树林区沉积物、红树植物以及双壳类动物体内重金属(Cu、Pb、Zn和Ni)的含量.总体看,沉积物中重金属含量与其他地点相比较低,红树植物根际沉积物中重金属含量高于光滩.红树植物组织内重金属含量较低,体内Pb、Zn的含量均低于根际沉积物,但对Cu、Ni有一定的富集,Cu可在根部和叶内富集,而Ni只在根部富集,并束缚于此.双壳类动物对4种重金属的吸收存在较大差异,Zn、Cu的富集明显高于Pb和Ni的富集程度.5种动物中又以岩蠔最高,体内的Zn、Cu分别达到3913, 378mg/g.从重金属含量看,作为食用动物有一定的风险. 相似文献