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Maike Schaefer und Tanja Juffernholz 《Umweltwissenschaften und Schadstoff-Forschung》2004,16(1):69-70
Ohne Zusammenfassung 相似文献
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Ralf Schulz Maike Hauschild Markus Ebeling Jakob Nanko-Drees Joem Wogram Mathias Liess 《Chemosphere》1998,36(15):3071-3082
A field method is described, which allows the qualitative estimation of pesticide contamination in the edgeof-field runoff. The method employs cheap and easy-to-use runoff sampling bottles, which were installed in an agricultural stream catchment over a period of three growing seasons. During this time 18 runoff events were detected, in nine of which insecticide contamination was measured (maximum concentrations: lindane 0.7 μg l−1 and 12.7 μg kg−1, parathion 20 μg l−1 and 728 μg kg−, fenvalerate 18.4 μg 1-1 and 924 μg kg−1). These insecticides were detected mainly as particle-bound chemicals. On about 80 % of the occasions the presence or absence of runoff measured in the field was in agreement with a simulation of runoff presence or absence using the runoff model KINEROS. 相似文献
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Katharina Schulz Maike Guschal Ingo Kowarik Jarcilene S. Almeida-Cortez Everardo V. S. B. Sampaio Arne Cierjacks 《Regional Environmental Change》2018,18(7):1969-1981
Grazing is the main land use in semi-arid regions of the world, and sustainable management practices are urgently needed to prevent their degradation. However, how different grazing intensities affect forest density and ecosystem functions is often not sufficiently understood to allow for management adaptations that safeguard the ecosystems and their functions in the long run. We assessed the aboveground carbon stocks and plant densities along a grazing gradient in the semi-arid seasonally dry tropical forest of north-eastern Brazil (Caatinga). On 45 study plots, we analysed the aboveground carbon stocks of the vegetation and determined forest density and recruitment as well as the population structure of the most abundant tree species. Grazing intensity was accounted for based on the weight of livestock droppings and classified as low, intermediate, or high. Mean aboveground carbon stock was 15.74?±?1.92 Mg ha?1 with trees and shrubs accounting for 89% of the total amount. Grazing at high intensities significantly reduced aboveground carbon stocks of herbs but not of other plant functional types. Instead, aboveground carbon stocks of trees and shrubs were negatively related to altitude above sea level, which is a proxy for reduced water availability along with lower anthropogenic impact. The population structure of the most common tree species was characterised by abundant recruitment, irrespective of grazing, whereas the recruitment of less frequent woody species was negatively affected by grazing. Overall, our data imply that grazing and forage management need to be adapted, including the reduction of free-roaming livestock and storage of fodder, to maintain carbon storage and forest density. 相似文献
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Stefan Siebert Friederike Anton-Erxleben Rainer Kiko Maike Kramer 《Marine Biology》2009,156(4):541-554
Various cnidarians have adapted their life style to interstitial habitats of marine sediments. Recently, for the first time
a hydroid was reported from the interstitial brine channel system of Arctic fast ice. Due to its derived features, the new
genus and species Sympagohydra tuuli was introduced. Here we describe findings of S. tuuli in sea ice at several sites within the central Arctic Ocean. In our view the results of this study do not allow assignment
of Sympagohydra to any known family and we, therefore, suggest the introduction of a new family Sympagohydridae which is placed within the
hydrozoan subclass Hydroidolina, order Anthomedusae, suborder Capitata. A first detailed histological analysis of S. tuuli is presented. In vivo analysis of locomotion and reproduction revealed a remarkable convergent evolution in S. tuuli and distant meiobenthic relatives. Shared traits are a flagellated epidermis enabling the animals to glide within small interstices
by means of flagellar beating as well as an internalised embryogenesis. In S. tuuli gametogenesis occurs in the absence of gonophores inbetween gastro- and epidermis clearly separated from the epidermis. Budding
was observed as the vegetative mode of reproduction. Documentation of feeding behaviour identified copepod nauplii and rotifers
as prey items and demonstrates a high trophical position of the hydroids within the sympagic food web. Occurrence of reproducing
individuals and pronounced tolerances towards changing temperatures and salinities indicate S.
tuuli as a truly sympagic species.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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Sustainability-oriented water management calls for scenarios of future water use. Model-based qualitative-quantitative scenarios
combine the development of story lines and the quantification of driving forces with the application of a water use model.
In order to support regional planning in two semi-arid Brazilian states suffering from water scarcity, the water use model
NoWUM was applied to derive two reference scenarios of municipality-specific sectorial water uses (irrigation, livestock,
household, industry and tourism), and to assess the impact of certain interventions. Until 2025, the extension of irrigation
accounts for almost 80% of the additional water withdrawals and for an even higher fraction of consumptive use in both scenarios.
Domestic and industrial use increases in regions with high immigration, but water use intensities can be controlled by appropriate
water pricing. A significant improvement of the developed scenarios is only possible if better data on water use and its driving
forces become available.
Electronic Publication 相似文献
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On the German island Norderney rabbit grazing effects on vegetation, soil and microclimate were investigated with exclosures
in different dune vegetation. Differences in species composition between grazed and ungrazed plots increased with grazing
activity. A decline in growth height resulted in higher light availability and temperature on the grazed sites. One of the
most visible effects was the decline in flowering plants. Most grazing effects varied between habitat types. Grey dunes were
distinctly affected by rabbit grazing. In relation to the habitat type, life forms were differently affected: in closed vegetation,
rabbit activities further open patches, resulting in more therophytes. In contrast, in open vegetation rabbit activities were
too strong and following sand dynamics too high for many therophytes. In general, grazing diversified habitats, slightly supported
the total species-richness, and enhanced the heterogeneity of species composition. Highest species-richness in total and of
herbs was reached at intermediate levels of grazing pressure. The study is in line that highest species-diversity will be
found at intermediate levels of disturbance and environmental stress and that grazing effects vary with the habitat type. 相似文献
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Timothée R. Cook Maike Hamann Lorien Pichegru Francesco Bonadonna David Grémillet Peter G. Ryan 《Marine Biology》2012,159(2):373-387
Knowledge on how divers exploit the water column vertically in relation to water depth is crucial to our understanding of
their ecology and to their subsequent conservation. However, information is still lacking for the smaller-bodied species,
due mostly to size constraints of data-loggers. Here, we report the diving behaviour of a flying diving seabird, the Cape
Cormorant Phalacrocorax capensis, weighing 1.0–1.4 kg. Results were obtained by simultaneously deploying small, high resolution and high sampling frequency
GPS and time-depth loggers on birds breeding on islands off Western South Africa (34°S, 18°E) in 2008. In all, dive category
was assigned to all dives performed by 29 birds. Pelagic dives occurred almost as frequently as benthic dives. Pelagic dives
were shallow (mean: 5 m) and took place over seafloors 5–100 m deep. Benthic dives were deeper, occurring on seafloors mainly
10–30 m deep. Dive shape was linked to dive category in only 60% of dives, while the descent rate, ascent rate and bottom
duration/dive duration ratio of a dive best explained its dive category. This shows that only the concomitant use of tracking
and depth tags can adequately classify diving strategies in a diver like the Cape Cormorant. Diet was mainly Cape Anchovy
Engraulis encrasicolis, suggesting that birds probably displayed two contrasted strategies for capturing the same prey. Flexible foraging techniques
represent an important key to survival inside the highly productive but heterogeneous Benguela upwelling ecosystem. 相似文献
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Stefan Nickel Winfried Schröder Roman Schmalfuss Maike Saathoff Harry Harmens Gina Mills Marina V. Frontasyeva Lambe Barandovski Oleg Blum Alejo Carballeira Ludwig de Temmerman Anatoly M. Dunaev Antoaneta Ene Hilde Fagerli Barbara Godzik Ilia Ilyin Sander Jonkers Zvonka Jeran Pranvera Lazo Sebastien Leblond Siiri Liiv Blanka Mankovska Encarnación Núñez-Olivera Juha Piispanen Jarmo Poikolainen Ion V. Popescu Flora Qarri Jesus Miguel Santamaria Martijn Schaap Mitja Skudnik Zdravko Špirić Trajce Stafilov Eiliv Steinnes Claudia Stihi Ivan Suchara Hilde Thelle Uggerud Harald G. Zechmeister 《Environmental Sciences Europe》2018,30(1):53