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81.
Despite a recent surge of interest in temporary lentic systems, a strong theory linking the biota to its environment has not
emerged. Using data from 10 temporary ponds at Mammoth Cave National Park, Kentucky, USA, we investigated how invertebrate
communities were structured along environmental gradients, both between and within ponds. Samples were collected with a benthic
corer in winter and spring, and a sweep net in spring. Six between-pond and two within-pond datasets were created. Between-pond
analyses yielded significant CCA’s with only one of the six data sets. The ranges of environmental variables (EV’s) within
ponds were often similar to the ranges of EV’s when averaged and compared between ponds. Some taxa were aggregated in a single
pond, and richness increased with pond area. The theory that richness increases with hydroperiod did not apply to these systems.
Within-pond analyses yielded more consistent relationships, with both CCA’s being significant. Sample depth was the best predictor
of invertebrate richness and abundance, with most taxa preferring shallow habitats. Richness and abundance were higher in
both shallow ponds and shallow areas of deep ponds than in deep areas of deep ponds. Standardizing sample depth may be an
effective way to remove this gradient as a confounding variable in future research. The presence of within-pond gradients,
possibly coupled with the limited dispersal and random colonization of tolerant taxa, makes between-pond comparisons difficult.
Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorised users.
Handling editor: S. Declerck 相似文献
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83.
E. V. Smirnova L. A. Gordova N. M. Timofeeva G. G. Shcherbakov 《Journal of Evolutionary Biochemistry and Physiology》2005,41(1):47-53
Distribution of activities of disaccharidases (saccharase, maltase), amino- and dipeptidases, dipeptidyl peptidase IV (DPP) and alkaline phosphatase along the small intestine and of these hydrolases in liver and kidney, as well as distribution of the digestive enzyme activities between the membrane and cytosol fractions of enterocytes is characterized in adult 6-month old pigs. It has been shown that maximum of the studied enzyme activities, except for DPP, takes place in ileum. A higher level of the activities of the soluble form of saccharase, maltase, and aminopeptidase M and a less significant level of the activity of the glycyl-L-leucine dipeptidase soluble form in jejunum and ileum is found than those in rats and monkeys. The obtained data demonstrate the existence of the complex enzyme system in small intestine, liver, and kidney that participate in realization of nutritive and trophic-barrier functions.Translated from Zhurnal Evolyutsionnoi Biokhimii i Fiziologii, Vol. 41, No. 1, 2005, pp. 39–43.Original Russian Text Copyright © 2005 by Smirnova, Gordova, Timofeeva, Shcherbakov. 相似文献
84.
85.
David B. Lindenmayer P. W. Lane P. S. Barton Mason Crane Karen Ikin Damian Michael Sachiko Okada 《Biodiversity and Conservation》2016,25(8):1587-1603
The long-term effectiveness of restored areas for biodiversity is poorly known for the majority of restored ecosystems worldwide. We quantified temporal changes in bird occurrence in restoration plantings of different ages and geometries, and compared observed patterns with a reference dataset from woodland remnants on the same farms as our plantings. Over time, bird species richness remained unchanged in spring but exhibited modest increases in winter. We found that wider plantings supported significantly greater bird species richness in spring and winter than narrow plantings. There was no evidence of a significant interaction between planting width and time. We recorded major temporal changes in the occurrence of a range of individual species that indicated a clear turnover of species as plantings matured. Our results further revealed marked differences in individual species occurrence between plantings and woodland remnants. Life-history attributes associated with temporal changes in the bird assemblage were most apparent in winter survey data, and included diet, foraging and nesting patterns, movement behaviour (e.g. migratory vs. dispersive), and body size. Differences in bird assemblages between plantings of different ages suggest that it is important that farms support a range of age classes of planted woodland, if the aim is to maximize the number of native bird species in restored areas. Our data also suggest that changes in the bird species occupying plantings of different ages can be anticipated in a broadly predictable way based on planting geometry (especially width) and key life-history attributes, particularly movement patterns and habitat and diet specialisation. 相似文献
86.
N. V. Oleneva 《Paleontological Journal》2016,50(11):1207-1296
The shell microstructure and microornament of 33 species of 28 spiriferid and spiriferinid genera from the Devonian of the East European Platform (Belarus, Central, Volga–Ural subregions), southern and middle Timan, and Transcaucasia are described. 相似文献
87.
The central role that cytochromes P450 play in the metabolism of drugs and other xenobiotics makes these enzymes a major subject for studies of drug disposition, adverse drug effects and drug-drug interactions. Despite tremendous success in elucidating structures and mechanisms of cytochrome P450 function, the concept of the drug-metabolizing ensemble as a functionally integrated system remains undeveloped. However, eukaryotic cells typically possess a multitude of different cytochromes P450 that are co-localized in the membrane of endoplasmic reticulum (ER); they interact with each other through the formation of dynamic heteromeric complexes (mixed oligomers). There has been growing appreciation of the importance of developing an approach to study the ensemble of cytochromes P450 as an integral system inspired growing interest of researchers to the principles of molecular organization of the microsomal monooxygenase system. Academician Archakov and his colleagues made important contributions to this field during the initial period of studies. Subsequent exploration of the molecular organization of the microsomal monooxygenase system as an integral multienzyme and multifunctional system have had an essential impact on our understanding of the key factors that determine the changes in human drug metabolism and other cytochrome P450-related functions in development and aging, as well as under the influence of various pathologies and environmental factors. 相似文献
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89.
A new method of gibberellin A3 detection based on high-performance liquid chromatography has been elaborated. It combines high accuracy and low cost, and includes the following stages: fixation with liquid nitrogen; extraction of alcohol-soluble substances; purification with freezing, reextraction in ethyl acetate, and thin-layer chromatography; and detection with HPLC. Chromatographic conditions and methods of substance identification have been determined. The method allows the use of modest amounts of plant material (5–20 g), at which variability does not exceed 7%, and the total loss of substance is approximately 3%. The results of gibberellin A3 detection in buckwheat are presented. 相似文献
90.