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31.
Recent plant diversity changes on Europe's mountain summits   总被引:2,自引:0,他引:2  
In mountainous regions, climate warming is expected to shift species' ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent (2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe's major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras' species richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (-1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region.  相似文献   
32.
Differential determination of fungal- and bacterial bioactivity in two spruce forest ecosystems To determine the general bioactivity and the contribution of actinomycetes and fungi in organic and mineral horizons of two spruce forests (Luvic Cambisol and Dystric Podzoluvisol) different physiological methods were utilized and compared. According to microbial measurements (ATP-quantity, heat output) the activity in Ebersberger Forst surpassed that of Höglwald in each horizon. The measurements of ergosterol and chitin delivered contradictory results. A similarity between the amount of glucosamine and that of fluorescein diacetate hydrolysis was observed. In the activity of lignin degrading fungi and ethylene production both soils differed entirely.  相似文献   
33.
Recent changes in agriculture (intensification or abandonment) have resulted in a critical reduction of semi-natural grasslands in Eastern Europe. Subalpine semi-natural grasslands in Transylvania, Romania, harbour a high diversity of plants and invertebrates, including endemics, and are considered refugia for numerous threatened open-land species. We investigated effects of land abandonment by examining species richness, species abundance, proportion of open-land, endemic and threatened vascular plants, gastropods, and diurnal and nocturnal Lepidoptera in extensive hay meadows (initial stage), and three seral stages of succession (early stage of abandoned hay meadow, naturally growing birch forest, and mature forest) in the mountainous region of Baisoara in Transylvania. A total of 626 species (225 vascular plants, 16 gastropods, 68 diurnal and 317 nocturnal Lepidoptera) were found in the 16 study sites (four replicates per successional stage). The four taxonomic groups differed in their response to the abandonment of hay meadows. Each stage of succession harboured the maximum species richness for one taxonomic group: extensive hay meadows for vascular plants, abandoned hay meadows for diurnal Lepidoptera, birch forests for nocturnal Lepidoptera, and mature forests for gastropods. In all four taxonomic groups the complementarity of species composition increased with successional age, whereas the number of characteristic open-land species decreased with successional age. The four successional stages did not differ in proportion of red-listed plant and diurnal Lepidoptera species. In nocturnal Lepidoptera, however, the proportion of red-listed species increased with successional age. Furthermore, successional stages did not differ in number of plant species endemic to the Carpathians and Eastern Europe. Our results indicate the high conservation value of all stages of subalpine grassland succession for the indigenous biodiversity of Transylvania. To prevent losses of characteristic species, we suggest a rotational grassland management program that maintains different successional stages.  相似文献   
34.
For the development of management strategies in sustainable agriculture it is necessary to describe and predict the role of soil microbes in different management systems. The classical approach uses the microbial biomass as the key parameter for the entire system, but for ecological purposes the variability of biotic parameters in time and space has to be better described. Moreover, the biomass active in the total soil profile or its most active zones should be used as a basis for the assessment of soil activity. The sum of adenylates was found to be more closely related to the microbial biomass than was ATP, which however appeared to be a better indicator for the microbial activity. Fatty acids from phospholipids were highly correlated with the soil microbial biomass. The pattern of fatty acids from soils under different long-term management indicated a high potential to typify the microbial community in soils and special organism populations. To overcome the problem, that only a small portion of the soil inhabiting microbes can be cultivated, first steps to use serological and genetical methods to directly identify or localize specific populations in the rhizosphere are shown.  相似文献   
35.
In non-flooded lowland rain forests with low soil phosphorus (P) in parts of Amazonia, P cycling largely occurs via leaf litter recycling by arbuscular mycorrhizal (AM) fungal symbionts. Occasional high input of P into these ecosystems occurs during drought years with increased litterfall. As the length and frequency of drought events are projected to increase in the region, a single-dose nutrient addition experiment was carried out to test how this would impact P cycling. An application rate of 4 kg P ha-1 was used, which corresponds to twice the amount of litter-derived P in an average year. It was hypothesized that i) the added mineral P would be immobilized by soil microorganisms, leading to measurable increase in soil microbial biomass carbon (C) and P and ii) AM colonization rate would be reduced by the pulse in mineral P available for plant uptake. The results did not support either of our hypotheses. The addition of P did not have an effect on AM root colonization, nor was P immobilized by soil microbiota during the experimental period. The lack of a difference between the control and treatment at our study site could be attributed to the relatively low one-off dose of P applied that did not change either the colonization rate of roots by AM fungi or the amount of soil available labile P. To obtain a mechanistic understanding of the availability, capture, and use of P by plant-symbiont associations in tropical rain forest ecosystems, further integrated studies of the soil-plant system combining long-term nutrient manipulations, modeling, and experimental approaches are required.  相似文献   
36.
Multifunctional pond fish farms in Hungary   总被引:1,自引:0,他引:1  
At the beginning of early 1990s the Food and Agriculture Organisation (FAO), the Organisation for Economic Cooperation and Development (OECD) and the European Union (EU) Commission effectively focused on multifunctionality, while in Hungary this term has only been highlighted in the last few years. As a consequence of the changes in Hungary in the last 15 years pond fish farms have had to explore their potential to find out how they can diversify their activities in order to be able to produce various fish products and to provide services for which there is demand from the market and the society. The application of the multifunctional approach has proved to be a realistic option for many fish farms for their survival and sustainable development. This paper demonstrates some examples of multifunctional fish farms, which clearly shows the business opportunities lying in the diversification of farm activities.  相似文献   
37.
38.
Experiments were undertaken in six Holstein-Friesian cattle to determine whether secretory IgA (SIgA) could be transported from serum into exocrine body fluids. Preliminary data indicated that when IgG1, IgG2, IgM and SIgA were administered i.v., only SIgA and IgG1 appeared in bile 90 min later at concentrations equal to or exceeding those in serum at the same time. Two hours post-injection, 70% of the SIgA recovered in bile was intact however only 30% co-precipitable with anti-secretory component (SC) while >90% of the administered IgA was precipitated by this method. All recovered IgG1 was of low molecular weight. More detailed studies indicated that the IgA recovered in bile 7 h post-injection or in milk 3 h post-injection, was predominately lower molecular weight than intact SIgA. Most of this low molecular weight radioactivity was TCA precipitable and ca 50% was dialyzable; these data indicate that TCA-precipitability is an inadequate criterion for determining whether intact SIgA is transported. The radioactivity recovered in parotid saliva was almost entirely non-TCA precipitable and dialyzable. Almost all SIgA recovered in bovine serum remained intact and had a of 15.7 h. When transport into milk and bile was calculated from total, recovered radioactivity (i.e. 29% and 2.7, respectively), data compared favorably with those conducted in sheep in which dimeric IgA (without SC) was administered i.v. When we calculated transport on the basis of recovered intact IgA, only 1.47 and 0.54% of the injected dose had been transported into milk and bile, respectively, 24 h later. Most IgA in ruminant bile may be of serum origin although the same appears to be unlikely for the IgA in milk.  相似文献   
39.
Wood Science and Technology - Two conifers and two deciduous wood species were irradiated by strong UV emitter mercury lamp at elevated temperatures up to 160 °C. Other series of...  相似文献   
40.
New molecular and biomarker approaches allow now a better understanding of the microbial diversity in soils. Examples are presented to demonstrate the new performance of these approaches and the quality of results. Investigations of the diversity of a bacterial indicator genus as well as studies of the whole microbial community structure are presented. Genotypes of Ochrobactrum were isolated by immunotrapping and characterized by PCR — fingerprinting. On a fallow land no significant changes in the intragenus diversity of this indicator bacterium was observed over a period of one year. In contrast, crop rotation was accompanied by a shift in the dominant genotypes of Ochrobactrum, while the genetic potential was not affected. Phospholipid fatty acid (PLFA)-pattern revealed significant shifts in the structure of the whole microbial community in a soil of a hop plantation as compared to a similar soil with crop rotation. The quantity of anaerobic bacteria, represented by the non-ester linked fatty acids were lower in soil samples derived from crop rotation as compared to a former hop plantation soil, which was contaminated with copper. In contrast, the ester linked fatty acids which are present in a wide range of Gram-negative and Gram-positive bacteria, exhibited a reverse relation. Soil samples of the hop plantation contained low amounts of saturated ester linked fatty acids branching on the 10th C atom. This indicates that actinomycetes are present in relative small proportions in the hop plantation soil.  相似文献   
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