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1.
《水生昆虫》2012,34(2):139-155
In the Volga Basin, the small Baikalian amphipod Gmelinoides fasciatus was introduced in 1965 into the Gorky reservoir in order to enhance fish production; it appeared in 1986 in the Rybinsk reservoir and we recorded it during monitoring activities in 2006 at Tver. In total, at the monitoring site Tver/Migalovo 69 benthic invertebrate taxa were identified. We compared data from three summer seasons. During summer low flow period Gmelinoides fasciatus did not exceed a share of 12.6% considering individual (ind) densities (mean abundance 165 ± 104 ind m?2) and 14.2% considering biomass (mean biomass 0.39 ± 0.44 g m?2). Abundances and biomass of G. fasciatus were shown to be stable over three years and no increase was observed. The monthly dataset (March–November 2008) revealed dynamics in relation to the native benthic communities and it was shown that the maximal densities of Gmelinoides did not exceed 587 ind m–2. Understanding the effects on benthic communities caused by the invasive amphipod Gmelinoides fasciatus is crucial in order to predict further developments in European inland waters and to establish management strategies.  相似文献   
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The recycling of metals is widely viewed as a fruitful sustainability strategy, but little information is available on the degree to which recycling is actually taking place. This article provides an overview on the current knowledge of recycling rates for 60 metals. We propose various recycling metrics, discuss relevant aspects of recycling processes, and present current estimates on global end‐of‐life recycling rates (EOL‐RR; i.e., the percentage of a metal in discards that is actually recycled), recycled content (RC), and old scrap ratios (OSRs; i.e., the share of old scrap in the total scrap flow). Because of increases in metal use over time and long metal in‐use lifetimes, many RC values are low and will remain so for the foreseeable future. Because of relatively low efficiencies in the collection and processing of most discarded products, inherent limitations in recycling processes, and the fact that primary material is often relatively abundant and low‐cost (which thereby keeps down the price of scrap), many EOL‐RRs are very low: Only for 18 metals (silver, aluminum, gold, cobalt, chromium, copper, iron, manganese, niobium, nickel, lead, palladium, platinum, rhenium, rhodium, tin, titanium, and zinc) is the EOL‐RR above 50% at present. Only for niobium, lead, and ruthenium is the RC above 50%, although 16 metals are in the 25% to 50% range. Thirteen metals have an OSR greater than 50%. These estimates may be used in considerations of whether recycling efficiencies can be improved; which metric could best encourage improved effectiveness in recycling; and an improved understanding of the dependence of recycling on economics, technology, and other factors.  相似文献   
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The aim of this article is to quantify the drivers for the changes in raw material consumption (domestic material consumption expressed in the form of all materials extracted and used in the production phase) in terms of technology, which refers to the concept of sustainable production; the product structure of final demand, which refers to the concept of sustainable consumption; and the volume of final demand, which is related to economic growth. We also aim to determine to what extent the technological development and a shift in product structure of the final demand compensate for the growth in final consumption volume. Therefore, we apply structural decomposition analysis (SDA) to the change in raw material consumption (RMC) of the Czech Republic between 2000 and 2007. To present the study in a broader context, we also show other material flow indicators for the Czech Republic for 2000 and 2007. Our findings of SDA show that final demand structure has a very limited effect on the change in material flows. The rapid change in final demand volume was not compensated for crude oil, metal ores, construction materials, food crops, and timber. For the material category of non‐iron metal ores, even the change in technology contributes to an increase in material flows. The largest relative increases are reported for non‐iron metal ores (38%) and construction materials (30%). The main changes in material flows related to the Czech Republic are driven by exports and enabled by imports, the main source of these increased material flows. This emphasizes the increasing role of international trade.  相似文献   
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  1. Urban areas are often considered to be a hostile environment for wildlife as they are highly fragmented and frequently disturbed. However, these same habitats can contain abundant resources, while lacking many common competitors and predators. The urban environment can have a direct impact on the species living there but can also have indirect effects on their parasites and pathogens. To date, relatively few studies have measured how fine‐scale spatial heterogeneity within urban landscapes can affect parasite transmission and persistence.
  2. Here, we surveyed 237 greenspaces across the urban environment of Edinburgh (UK) to investigate how fine‐scale variation in socio‐economic and ecological variables can affect red fox (Vulpes vulpes) marking behavior, gastrointestinal (GI) parasite prevalence, and parasite community diversity.
  3. We found that the presence and abundance of red fox fecal markings were nonuniformly distributed across greenspaces and instead were dependent on the ecological characteristics of a site. Specifically, common foraging areas were left largely unmarked, which indicates that suitable resting and denning sites may be limiting factor in urban environments. In addition, the amount of greenspace around each site was positively correlated with overall GI parasite prevalence, species richness, and diversity, highlighting the importance of greenspace (a commonly used measure of landscape connectivity) in determining the composition of the parasite community in urban areas.
  4. Our results suggest that fine‐scale variation within urban environments can be important for understanding the ecology of infectious diseases in urban wildlife and could have wider implication for the management of urban carnivores.
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Species loss leads to community closure   总被引:1,自引:0,他引:1  
Global extinction of a species is sadly irreversible. At a local scale, however, extinctions may be followed by re-invasion. We here show that this is not necessarily the case and that an ecological community may close its doors for re-invasion of species lost from it. Previous studies of how communities are assembled have shown that there may be rules for that process and that limitations are set to the order by which species are introduced and put together. Instead of focusing on the assembly process we randomly generated simple competitive model communities that were stable and allowed for two to 10 coexisting species. When a randomly selected single species was removed from the community, the cascading species loss was recorded and frequently the resulting community was more than halved. Cascading extinctions have previously been recorded, but we here show that the relative magnitude of the cascade is dependent on community size (and not only trophic structure) and that the reintroduction of the original species lost often is impossible. Hence, species loss does not simply leave a void potentially refilled, but permanently alters the entire community structure and consequently the adaptive landscape for potential re-invaders.  相似文献   
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1. Small, vertebrate carrion is a significant input into terrestrial ecosystems. The relative importance of different recyclers of carrion is poorly understood because of seasonal and habitat variation and methodological differences among studies. Many studies, in particular, do not account adequately for the activity of burying beetles (Nicrophorus spp.). 2. The present work, utilising a previously unstudied woodland, addresses this concern by: placing only two carcasses in the field at one time, using microsites only once, and providing a means to easily recover successful burying beetles. 3. Burying beetles buried 77.5% of experimental mouse carcasses over their breeding season, and typically did so within three activity periods after placement (30 of 31 burials). 4. The results and a brief review suggest that burying beetles are the dominant summer competitor for small, vertebrate carrion in mid‐ and northern latitude woodlands. Information on the age of carcasses utilised by burying beetles also provides an ecological context for laboratory studies of behaviour, life history, and microbial interactions.  相似文献   
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