Search Results - (Author, Cooperation:L. Oksanen)
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1Latest Papers from Table of Contents or Articles in PressJ. A. Estes ; J. Terborgh ; J. S. Brashares ; M. E. Power ; J. Berger ; W. J. Bond ; S. R. Carpenter ; T. E. Essington ; R. D. Holt ; J. B. Jackson ; R. J. Marquis ; L. Oksanen ; T. Oksanen ; R. T. Paine ; E. K. Pikitch ; W. J. Ripple ; S. A. Sandin ; M. Scheffer ; T. W. Schoener ; J. B. Shurin ; A. R. Sinclair ; M. E. Soule ; R. Virtanen ; D. A. Wardle
American Association for the Advancement of Science (AAAS)
Published 2011Staff ViewPublication Date: 2011-07-19Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Animals ; Biodiversity ; *Ecosystem ; *Extinction, Biological ; Feeding Behavior ; *Food Chain ; Humans ; Introduced Species ; Population Dynamics ; Predatory BehaviorPublished by: -
2Articles: DFG German National LicensesOksanen, L. ; Ekerholm, P. ; Oksanen, T. ; Henttonen, H. ; Turchin, P.
[s.l.] : Macmillian Magazines Ltd.
Published 2000Staff ViewISSN: 1476-4687Source: Nature Archives 1869 - 2009Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsNotes: [Auszug] Large oscillations in the populations of Norwegian lemmings have mystified both professional ecologists and lay public. Ecologists suspect that these oscillations are driven by a trophic mechanism: either an interaction between lemmings and their food supply, or an interaction between lemmings ...Type of Medium: Electronic ResourceURL: -
3Articles: DFG German National LicensesStaff View
ISSN: 1432-2056Source: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract Vegetation on Bear Island, Jan Mayen and Spitsbergen was investigated along altitudinal and topographic gradients in order to describe the main patterns in plant community distributions and compare them with those on the mainland. In a numerical classification the communities were distinctly differentiated; however, physiognomically similar Racomitrium and Sanionia communities dominated in most habitats on Bear Island and Jan Mayen. On Spitsbergen, moss-dominated communities prevailed in depression sites. High-altitude sites were occupied either by moss-dominated communities or by variable assemblages of fragmented moss cover and scattered vascular plants. Dwarf shrub and grass heaths that were common on the mainland did not occur on grazer-free Bear Island and Jan Mayen, and were confined to the lowest altitudes on Spitsbergen. The lack of grazers on Bear Island and Jan Mayen accounts in part for the differences in vegetation between the mainland and the islands.Type of Medium: Electronic ResourceURL: -
4Articles: DFG German National LicensesStaff View
ISSN: 1432-1203Source: Springer Online Journal Archives 1860-2000Topics: BiologyMedicineNotes: Abstract Mutational analysis of the promoter region of the leptin gene in morbidly obese Finnish subjects had revealed a previously unidentified C(–188)A polymorphism in the proximal promoter that showed a weak association with elevated serum leptin levels in obese male carriers of the variant (–188A) allele. In this study we demonstrated that neither expression of reporter gene constructs driven by wild-type (–188C) or variant (–188A) proximal promoter regions, nor assay of binding of cellular proteins reveal a genotype-related difference in promoter activity.Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesStaff View
ISSN: 1432-1939Keywords: Key words Importance of competition ; Productivity ; Removal experiments ; Tundra ; Wooded meadowSource: Springer Online Journal Archives 1860-2000Topics: BiologyNotes: Abstract The effect of community productivity on competition was studied in 82 permanent plots using two removal experiments with the rhizomatous perennial grass Anthoxanthum odoratum. The removal of neighbouring plants had a positive effect on the number of shoots and total above-ground biomass of Anthoxanthum but no significant effect on mean shoot biomass. The relative competition intensity coefficient (RCI) calculated from these data showed that competition intensity increased with increasing community productivity. Similarly, the importance of competition and the difference between local maximum and local average population density increased with increasing community productivity. We concluded that for Anthoxanthum the impact of competition is greater in high-productivity areas and that competition reduces population density. No evidence was found supporting the importance of positive interactions between plants in tundra areas.Type of Medium: Electronic ResourceURL: