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1.
Frauke Ecke Pernilla Christensen Per Sandström Birger Hörnfeldt 《Landscape Ecology》2006,21(4):485-497
Several studies indicate a long-term decline in numbers of different species of voles in northern Fennoscandia. In boreal Sweden, the long-term decline is most pronounced in the grey-sided vole (Clethrionomys rufocanus). Altered forest landscape structure has been suggested as a possible cause of the decline. However, habitat responses of grey-sided voles at the landscape scale have never been studied. We analyzed such responses of this species in lowland forests in Västerbotten, northern Sweden. Cumulated spring densities representing 22 local time series from 1980–1999 were obtained by a landscape sampling design and were related to the surrounding landscape structure of 2.5×2.5 km plots centred on each of the 22 1-ha trapping plots. In accordance with general knowledge on local habitat preferences of grey-sided voles, our study supported the importance of habitat variables such as boulder fields and old-growth pine forest at the landscape scale. Densities were negatively related to clear cuts. Habitat associations were primarily those of landscape structure related to habitat fragmentation, distance between habitat patches and patch interspersion rather than habitat patch type quantity. Local densities of the grey-sided vole were positively and exponentially correlated with spatial contiguity (measured with the fragmentation index) of old-growth pine forest, indicating critical forest fragmentation thresholds. Our results indicate that altered land use might be involved in the long-term decline of the grey-sided vole in managed forest areas of Fennoscandia. We propose two further approaches to reveal and test responses of this species to changes in landscape structure. 相似文献
2.
Marc-Oliver Aust Sören Thiele-Bruhn Juliane Seeger Frauke Godlinski Ralph Meissner Peter Leinweber 《Water, air, and soil pollution》2010,209(1-4):143-156
Sulfonamide antibiotics can enter agricultural soils by fertilisation with contaminated manure. While only rough estimations on the extent of such applications exist, this pathway results in trace level contamination of groundwater. Therefore, we studied the transport of three sulfonamides in leachates from field lysimeters after application of a sulfonamide-contaminated liquid manure. In a 3-year period, the sulfonamides were determined in 64% to 70% of all leachate samples at concentrations between 0.08 to 56.7 µg L?1. Furthermore, sulfonamides were determined in leachates up to 23 months after application, which indicated a medium- to long-term leaching risk. Extreme dry weather conditions resulted in highest dislocated amounts of sulfonamides in two of the three treatments. Furthermore, soil management such as tillage and cropping affected the time between application and breakthrough of sulfonamides and the intra-annual distribution of sulfonamide loads in leachates. Although the total sulfonamide leaching loads were low, the concentrations exceeded the limit value of the European Commission of 0.1 µg biocide L?1 in drinking water in more than 50% of all samples. Furthermore, the medium-term mean concentration of the sulfonamides ranged from 0.08 and 4.00 µg L?1, which was above the limit value of the European Commission in 91 out of 158 samples. Therefore, sulfonamides applied to soils in liquid manure under common agricultural practice may cause environmental and health risks which call for a setting up of more long-term studies on the fate of antibiotics. 相似文献
3.
Frauke Kleemann Maximilian von Fragstein Barbara Vornam Annika Müller Christoph Leuschner Andrea Holzschuh Teja Tscharntke Reiner Finkeldey Andrea Polle 《European Journal of Forest Research》2011,130(5):707-716
Knowledge on phenological, morphometric, and phytochemical variation of local progenies of European aspen (Populus tremula, L.) is limited. The goal of this study was to characterize variation in growth and ecologically important leaf properties
in aspen full-sib families in relation to interacting organisms (mycorrhiza, endophytes, and insects) and to determine whether
these interactions were affected by soil application of a systemic fungicide. In local progenies, within-family variation
of neutral molecular genetic markers (nuclear microsatellites) was higher than between families. Significant variation in
growth, production of phenolic defensive compounds and other phytochemical leaf traits was found between families. Phenolic
compounds showed clear negative correlation with generalist herbivores, but did not result in negative trade-off with biomass
production. Differences in mycorrhizal colonization were not found among full-sib families and application of a systemic fungicide
suppressed neither mycorrhizal colonization nor infestation with insects. However, a strong suppression of endophytes occurred,
whose long-term consequences may require attention when fungicides are used in agroforestry plantations. 相似文献
4.
Ménot G Bard E Rostek F Weijers JW Hopmans EC Schouten S Sinninghe Damsté JS 《Science (New York, N.Y.)》2006,313(5793):1623-1625
During the Last Glacial Maximum, the sea-level lowstand combined with the large extent of the Fennoscandian and British ice sheets led to the funneling of European continental runoff, resulting in the largest river system that ever drained the European continent. Here, we show an abrupt and early reactivation of the European hydrological cycle at the onset of the last deglaciation, leading to intense discharge of the Channel River into the Bay of Biscay. This freshwater influx, probably combined with inputs from proglacial or ice-dammed lakes, dramatically affected the hydrology of the region, both on land and in the ocean. 相似文献
5.
Various process-based models are extensively being used to analyze and forecast catchment hydrology and water quality. However, it is always important to select the appropriate hydrological and water quality modeling tools to predict and analyze the watershed and also consider their strengths and weaknesses. Different factors such as data availability, hydrological, hydraulic, and water quality processes and their desired level of complexity are crucial for selecting a plausible modeling tool. This review is focused on suitable model selection with a focus on desired hydrological, hydraulic and water quality processes (nitrogen fate and transport in surface, subsurface and groundwater bodies) by keeping in view the typical lowland catchments with intensive agricultural land use, higher groundwater tables, and decreased retention times due to the provision of artificial drainage. In this study, four different physically based, partially and fully distributed integrated water modeling tools, SWAT (soil and water assessment tool), SWIM (soil and water integrated model), HSPF (hydrological simulation program– FORTRAN) and a combination of tools from DHI (MIKE SHE coupled with MIKE 11 and ECO Lab), have been reviewed particularly for the Tollense River catchment located in North-eastern Germany. DHI combined tools and SWAT were more suitable for simulating the desired hydrological processes, but in the case of river hydraulics and water quality, the DHI family of tools has an edge due to their integrated coupling between MIKE SHE, MIKE 11 and ECO Lab. In case of SWAT, it needs to be coupled with another tool to model the hydraulics in the Tollense River as SWAT does not include backwater effects and provision of control structures. However, both SWAT and DHI tools are more data demanding in comparison to SWIM and HSPF. For studying nitrogen fate and transport in unsaturated, saturated, and river zone, HSPF was a better model to simulate the desired nitrogen transformation and transport processes. However, for nitrogen dynamics and transformations in shallow streams, ECO Lab had an edge due its flexibility for inclusion of user-desired water quality parameters and processes. In the case of SWIM, most of the input data and governing equations are similar to SWAT but it does not include water bodies (ponds and lakes), wetlands and drainage systems. In this review, only the processes that were needed to simulate the Tollense River catchment were considered, however the resulted model selection criteria can be generalized to other lowland catchments in Australia, North-western Europe and North America with similar complexity. 相似文献
6.
Bone char as phosphorus fertilizer involved in cadmium immobilization in lettuce,wheat, and potato cropping 总被引：1，自引：0，他引：1 
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下载免费PDF全文 Bone char is a potential clean and renewable P fertilizer with Cd‐immobilization capabilities, but the P–Cd interactions in cropping of vegetable, grain, and tuber crops are unknown. In the present pot experiment bone char was evaluated on its effect on the growth and P supply of various crops (lettuce, wheat, potatoes) as well as its capability to reduce the uptake of Cd from a moderately Cd‐contaminated and P‐deficient soil (soil 1) and a highly Cd‐contaminated soil with sufficient P supply (soil 2). When averaging the dry‐matter yield over the treatments for each crop for the P‐sufficient soil 1, the following order was obtained: triple superphosphate (TSP) > diammonium phosphate (DAP) > BC, whereas for the soil 2 with sufficient P supply it was inverted with BC > DAP > TSP. The P‐deficiency resulted in a more pronounced effect of TSP and DAP on the plant growth, whereas P sufficiency in the soil promoted a crop‐quality‐enhancing effect of bone char. The Cd concentration in the consumption‐relevant plant parts was mostly insignificantly affected by treatments; however, the total Cd concentration in the whole plants tended to decrease with fertilizer addition for all crops in soil 1 even at very low bone‐char application levels. Similar results were obtained for soil 2 with an exception for the Cd concentration in potatoes, as the total Cd concentration was significantly increased in the TSP and DAP treatments. This most likely results from the introduction of Cd with TSP and DAP as they contained ≈ 27–28 mg Cd kg–1. Thus, this study demonstrated the potential of bone char as a clean P fertilizer, which can efficiently decrease the Cd contamination of potato on contaminated soils. 相似文献
7.
Birger Hörnfeldt Pernilla Christensen Per Sandström Frauke Ecke 《Landscape Ecology》2006,21(7):1135-1150
Over the past three decades in boreal Sweden, there has been a long-term decline of cyclic sympatric voles, leading to local
extinctions of the most affected species, the grey-sided vole (Clethrionomys rufocanus). We monitored this decline by snap-trapping on 58 permanent plots spread over 100 km2 in spring and fall from fall 1971–2003. The reason for the decline is largely unknown, although a common major factor is
likely to be involved in the decline of C. rufocanus and of the coexisting voles. However, here we deal with the reasonability of one complementary hypothesis, the habitat fragmentation
hypothesis, which assumes that part of the decline of C. rufocanus is caused by habitat (forest) destruction. There was considerable local variation in the decline among the 58 1-ha sampling
plots, with respect to both density and timing of the decline; however, all declines ended up with local extinction almost
without exception. Local declines were not associated with habitat destruction by clear-cutting within sampling-plots, as
declines started about equally often before as after clear-cutting, which suggested that habitat destruction outside sampling
plots could be involved. In a multiple regression analysis, local habitat preference (LHP; expressed as a ratio of observed
to expected number of voles trapped per habitat) together with two habitat variables in the surrounding (2.5×2.5 km2) landscape matrix explained 56% of the variation among local cumulated densities of C. rufocanus and hence of local time-series. LHP was positively correlated and explained 31% of the variation, while connectivity among
clear-cuts was negatively correlated and proximity among xeric-mesic mires was positively correlated and explained additional
16% and 9%, respectively. Even if the overall decline cannot be connected to local clear-cutting on sampling-plots, clear-cutting
and hence habitat fragmentation/destruction in the surrounding landscapes potentially influenced grey-sided vole numbers negatively. 相似文献
8.
Spiral-defect populations in low-Prandtl number Rayleigh-Bénard convection with slow rotation about a vertical axis were measured in carbon dioxide at high pressure. The results indicate that spirals act like "thermally excited" defects and that the winding direction of a spiral is analogous to a magnetic spin. Rotation about a vertical axis, the spiral analog of the magnetic field, breaks the zero-rotation chiral symmetry between clockwise and counterclockwise spiral defects. Many properties of spiral-defect statistics are well described by an effective statistical-mechanical model. 相似文献
9.
Beck M Förster F Ecke M Plitzko JM Melchior F Gerisch G Baumeister W Medalia O 《Science (New York, N.Y.)》2004,306(5700):1387-1390
Nuclear pore complexes (NPCs) are gateways for nucleocytoplasmic exchange. To analyze their structure in a close-to-life state, we studied transport-active, intact nuclei from Dictyostelium discoideum by means of cryoelectron tomography. Subvolumes of the tomograms containing individual NPCs were extracted in silico and subjected to three-dimensional classification and averaging, whereby distinct structural states were observed. The central plug/transporter (CP/T) was variable in volume and could occupy different positions along the nucleocytoplasmic axis, which supports the notion that it essentially represents cargo in transit. Changes in the position of the CP/T were accompanied by structural rearrangements in the NPC scaffold. 相似文献
10.
Lena K. Kottmeier Frauke Seehusen Martin Helweg Karl Rohn Peter Stadler Maren Hellige 《Veterinary radiology & ultrasound》2020,61(1):48-57
Magnetic resonance imaging and the correlation to histopathological findings of the equine palmar foot of lame horses have been described previously, using 0.27 and 1.5 T systems. Compared to these, 3 T systems provide superior spatial resolution and imaging contrast. The aim of our prospective anatomic study was to characterize the imaging anatomy of the navicular region on 3 T MRI in comparison to histopathological findings. We hypothesized that 3 T MRI allows a good visualization of the entire navicular apparatus and reliable measurements of navicular cartilage and cortical bone thickness. Twenty front feet of sound horses were examined using a 3 T MRI system. For histopathological examination, sagittal tissue sections of the navicular bones and adjacent ligaments were prepared. Alterations in magnetic resonance signal were graded for each region and compared to corresponding histological slices. Overall, there was good visualization of the anatomical detail and a very good agreement between MRI and histology for compact bone and spongiosa, good agreement for the fibrocartilage and the distal sesamoidean impar ligament, but only moderate agreement for the hyaline cartilage and the collateral sesamoidean ligament. A comparative measurement of cartilage and cortical bone thickness on magnetic resonance images and histological sections was performed. In MRI, the hyaline cartilage of the articular surface appeared significantly thinner and the fibrocartilage of the flexor surface appeared significantly thicker compared to histology. Findings indicated that MRI at a field strength of 3 T allows reliable depiction of anatomic details of the navicular apparatus. 相似文献