Small-scale effects of historical land use and topography on post-cultural tree species composition in an Alpine valley in southern Switzerland   总被引：1，自引：0，他引：1  

Sina Muster  Helmut Elsenbeer  Marco Conedera 《Landscape Ecology》2007,22(8):1187-1199

Investigations of spatial patterns in forest tree species composition are essential in the understanding of landscape dynamics, especially in areas of land-use change. The specific environmental factors controlling the present patterns, however, vary with the scale of observation. In this study we estimated abundance of adult trees and tree regeneration in a Southern Alpine valley in Ticino, Switzerland. We hypothesized that, at the present scale, spatial pattern of post-cultural tree species does not primarily depend on topographic features but responds instead to small-scale variation in historical land use. We used multivariate regression trees to relate species abundances to environmental variables. Species matrices were comprised of single tree species abundance as well as species groups. Groups were formed according to common ecological species requirements with respect to shade tolerance, soil moisture and soil nutrients. Though species variance could only be partially explained, a clear ranking in the relative importance of environmental variables emerged. Tree basal area of formerly cultivated Castanea sativa (Mill.) was the most important factor accounting for up to 50% of species’ variation. Influence of topographic attributes was minor, restricted to profile curvature, and partly contradictory in response. Our results suggest the importance of biotic factors and soil properties for small-scale variation in tree species composition and need for further investigations in the study area on the ecological requirements of tree species in the early growing stage.  相似文献   

Metabolic phenotyping of mouse mutants in the German Mouse Clinic     

Ralf ELVERT  Nicole EHRHARDT  Martin TAUBE  Martin KLINGENSPOR  Valerie GAILUS‐DURNER  Helmut FUCHS  Martin Hrabe DE ANGELIS  Veronique BLANQUET  Gerhard HELDMAER 《Integrative zoology》2006,1(3):122-125

The German Mouse Clinic was established as a phenotyping center to provide the scientific community with systematic standardized phenotyping of mouse models from various genetic backgrounds. We found metabolic phenotypes in nine out of 20 mutant lines screened in a primary screen. Based on these findings, the mutants were analyzed in secondary and tertiary screens. Mice of a sample mutant line, isolated from the ENU‐screen at the National Research Center for Environment and Health in Munich, were found to have lower body weight, consume less food, but have higher ratios of metabolized energy per unit body weight compared with their wild‐type littermates. Basal metabolic rate and heat production were simultaneously increased by 16–18%, whereas body fat content was reduced by 11–16%. The combination of various parameters of energy consumption, expenditure and energy storage illustrate the metabolic demands of the sample mutant mouse line and demonstrate the utility of the powerful phenotyping tool used at the German Mouse Clinic.  相似文献   

Productivity is a poor predictor of plant species richness   总被引：5，自引：0，他引：5  

Adler PB  Seabloom EW  Borer ET  Hillebrand H  Hautier Y  Hector A  Harpole WS  O'Halloran LR  Grace JB  Anderson TM  Bakker JD  Biederman LA  Brown CS  Buckley YM  Calabrese LB  Chu CJ  Cleland EE  Collins SL  Cottingham KL  Crawley MJ  Damschen EI  Davies KF  DeCrappeo NM  Fay PA  Firn J  Frater P  Gasarch EI  Gruner DS  Hagenah N  Hille Ris Lambers J  Humphries H  Jin VL  Kay AD  Kirkman KP  Klein JA  Knops JM  La Pierre KJ  Lambrinos JG  Li W  MacDougall AS  McCulley RL  Melbourne BA  Mitchell CE  Moore JL  Morgan JW  Mortensen B 《Science (New York, N.Y.)》2011,333(6050):1750-1753

For more than 30 years, the relationship between net primary productivity and species richness has generated intense debate in ecology about the processes regulating local diversity. The original view, which is still widely accepted, holds that the relationship is hump-shaped, with richness first rising and then declining with increasing productivity. Although recent meta-analyses questioned the generality of hump-shaped patterns, these syntheses have been criticized for failing to account for methodological differences among studies. We addressed such concerns by conducting standardized sampling in 48 herbaceous-dominated plant communities on five continents. We found no clear relationship between productivity and fine-scale (meters(-2)) richness within sites, within regions, or across the globe. Ecologists should focus on fresh, mechanistic approaches to understanding the multivariate links between productivity and richness.  相似文献   

Human appropriation of net primary production     

Haberl H  Krausmann F  Erb KH  Schulz NB 《Science (New York, N.Y.)》2002,296(5575):1968-9; author reply 1968-9

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Determination of Potassium Delivery to the Roots of Cereal Plants     

Stefan Gth  Helmut Meuser  Carl-Andreas Abitz  Gerd Wessolek  Manfred Renger 《植物养料与土壤学杂志》1989,152(2):143-149

Potassium (K) delivery to the roots of cereal plants in soils is determined by both soil and plant factors, root growth and root length density in particular, being of major importance. In Part A of this paper an evaluative framework is shown for sandy and loamy-silty soils for determination of root length density based on available field capacity, soil depth in 10 cm steps and the climatic water balance. A good correlation (r² = 0.86) was found when the root length densities were determined at ear emergence. With the help of correction functions root length densities can be subsequently estimated for the other phenological stages (stem elongation, flowering and yellow ripeness). The method described is suited for determining root length densities in water and nutrient transport simulation models. In Part B exchange resins were used to simulate the K delivery from the soil to the root. Measurements were made for different soils and water contents. The depletion zone near the exchange resin was 6 mm thick after 4 days. This corresponds to results obtained from root measurements. Comparisons between a sandy and a loamy-silty soil show, that K delivery by diffusion for equal concentrations depends primarily on soil moisture and pore tortuosity. This leads to the conclusion, that soil physical properties must be taken into consideration when evaluating chemical soil analysis and recommendating fertilizer applications.  相似文献   

Lead and cesium transport in european forest soils     

Dörr  Helmut  Münnich  Karl Otto 《Water, air, and soil pollution》1991,(1):809-818

The downward velocity of Pb and Cs in undisturbed European forest soils is determined from the depth distribution of atmospheric ²¹⁰Pb , and from the penetration depth of the bomb Cs peak in the soil. The downward velocity of Pb and Cs shows no correlation with soil type and pH. The downward migration of Pb and Cs is found to be due to an apparent downward movement of organic material, caused by the sedimentation of soil organic matter and subsequent turnover into CO₂ . Cs migration, however, shows an additional velocity component which is found to depend on the turnover rate of soil organic matter.  相似文献   

Vorarbeiten zur monographischen Darstellung von Wildpflanzensortimenten:Secale L     

Karl Hammer  Ewa Skolimowska  Helmut Knüpffer 《Genetic Resources and Crop Evolution》1987,35(2):135-177

Zusammenfassung Die Genbank in Gatersleben verfügt über eine umfangreiche Wildroggen-Kollektion, die für die Aufgaben der Züchtungsforschung und Züchtung zur Verfügung steht. Probleme der Erhaltung dieser Kollektion in der Genbank werden diskutiert. In diesem Zusammenhang wird das Reproduktionssystem besonders untersucht.Zur Dokumentation des Materials ist seine Identifikation notwendig. Daher wurde die GattungSecale revidiert. Neukombinationen werden fürS. strictum (Presl) Presl — subsp.kuprijanovii (Grossh.) Hammer, subsp.anatolicum (Boiss.) Hammer, subsp.ciliatoglume (Boiss.) Hammer, subsp.africanum (Stapf) Hammer — und fürS. cereale L. — subsp.afghanicum (Vav.) Hammer — vorgeschlagen. Zur Determination der Sippen wird ein Bestimmungsschlüssel publiziert.Entwicklungstendenzen innerhalb der Gattung werden aufgezeigt.

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Preliminary work on monographs of wild plant collections:Secale L

Summary The Gatersleben gene bank holds a large collection of wild rye available for the tasks of breeding research and plant breeding. Problems of maintaining this collection in the gene bank are discussed. In this connection the breeding system is especially studied.A proper identification of the material is a necessary prerequisite for its documentation. Therefore, the genusSecale was revised. New combinations are proposed forS. strictum (Presl) Presl — subsp.kuprijanovii (Grossh.) Hammer, subsp.anatolicum (Boiss.) Hammer, subsp.ciliatoglume (Boiss.) Hammer, subsp.africanum (Stapf) Hammer — and forS. cereale L. — subsp.afghanicum (Vav.) Hammer. Keys for the determination of species and subspecies are given.Evolutionary trends within the genus are demonstrated.

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: Secale L

, . . . . Secale. . S. strictum (Presl) Presl — subsp.kuprijanovii (Grossh.) Hammer, subsp.anatolicum (Boiss.) Hammer, subsp.ciliatoglume (Boiss.) Hammer, subsp.africanum (Stapf) Hammer — S. cereale L. — subsp.afghanicum (Vav.) Hammer. . .

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Herrn Prof. Dr. Dr. h. c. mult.H. Stubbe aus Anlaß der 85. Wiederkehr seines Geburtstages gewidmet.

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Der Beitrag von E. S. entstand im Ergebnis eines Studienaufenthaltes zur Vorbereitung ihrer Dissertation 1986 in Gatersleben.  相似文献   

Schadstoffpotential technogener Substrate in Böden urban-industrieller Verdichtungsräume     

Helmut Meuser 《植物养料与土壤学杂志》1996,159(6):621-628

Potential of contamination of technological substrates in soils of urban and industrial environments The soils of urban and industrial environments are often present in form of anthropogenic Deposols made of natural and technological substrates. The admixture of technological substrates can be connected with the accumulation of contaminants. On the basis of extensive investigations in the central Ruhr area and literature studies the contamination level (parameters: As, Cd, Cr, Cu, Hg, Ni, Pb, Zn, Benzo(a)pyrene, Σ PCB) of the different technological substrates is characterized. The volume of data permits to establish an assessment scheme for the contamination level of technological substrates with a five stage scale (very low, low, middle, high, very high).  相似文献   

Gewebekulturen aus Alkaloidpflanzen     

Anneliese Romeike  Helmut Koblitz 《Genetic Resources and Crop Evolution》1972,20(1):165-171

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Mobilization of cesium in organic rich soils: Correlation with production of dissolved organic carbon     

Ina Tegen  Helmut Dörr 《Water, air, and soil pollution》1996,88(1-2):133-144

A study of the downward movement of ¹³⁷Cs in an undisturbed forest soil is presented. Seasonal variations and depth profiles of ¹³⁷Cs activities were measured in seepage water, which is the transport medium for the downward movement of anthropogenic substances in soils. Furthermore the correlation of ¹³⁷Cs mobilization and production of dissolved organic carbon (DOC) was investigated. Seasonal variations of both ¹³⁷Cs and DOC fluxes in the seepage water in a depth of 5 cm depth were observed, where the maximum fluxes in the summer months were about one order of magnitude higher than the minimum fluxes in the winter months. ¹³⁷Cs fluxes are found to be correlated with DOC fluxes with a correlation coefficient of r = 0.63, and both are highly correlated with soil temperature. This indicates that cesium is bound to soil organic material. The production of DOC is controlled by microbial decomposition of soil organic matter and we assume that this holds true for the ¹³⁷Cs release as well. The actual transport velocity (0.2 ± 0.14 mm/a) of ¹³⁷Cs (calculated by the weighed mean of ¹³⁷Cs concentration in the seepage water and the total ¹³⁷Cs content of the soil) is about one order of magnitude less than the mean transport velocity (1.2 ± 0.3 mm/a) over the past 25 years (calculated from the ¹³⁷Cs depth profile). It is possible that the transport velocity of ¹³⁷Cs in undisturbed soils decreases with time as it binds to aged organic material which is less easily decomposable than fresh organic material.  相似文献