GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    PLANT COMPETITION UNDERGROUND (1997)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Ecology, Evolution, and Systematics 28 (1997), S. 545-570 
    Details
    ISSN: 0066-4162
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Notes: Abstract Belowground competition occurs when plants decrease the growth, survival, or fecundity of neighbors by reducing available soil resources. Competition belowground can be stronger and involve many more neighbors than aboveground competition. Physiological ecologists and population or community ecologists have traditionally studied belowground competition from different perspectives. Physiologically based studies often measure resource uptake without determining the integrated consequences for plant performance, while population or community level studies examine plant performance but fail to identify the resource intermediary or mechanism. Belowground competitive ability is correlated with such attributes as root density, surface area, and plasticity either in root growth or in the properties of enzymes involved in nutrient uptake. Unlike competition for light, in which larger plants have a disproportionate advantage by shading smaller ones, competition for soil resources is apparently more symmetric. Belowground competition often decreases with increases in nutrient levels, but it is premature to generalize about the relative importance of above- and belowground competition across resource gradients. Although shoot and root competition are often assumed to have additive effects on plant growth, some studies provide evidence to the contrary, and potential interactions between the two forms of competition should be considered in future investigations. Other research recommendations include the simultaneous study of root and shoot gaps, since their closures may not occur simultaneously, and improved estimates of the belowground neighborhood. Only by combining the tools and perspectives from physiological ecology and population and community biology can we fully understand how soil characteristics, neighborhood structure, and global climate change influence or are influenced by plant competition belowground.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.ecolsys.28.1.545
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    The efficiency of pollen transfer and rates of embryo initiation in Cryptantha (Boraginaceae) (1983)
    Springer
    Oecologia 59 (1983), S. 262-268 
    Details
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The efficiency of pollination and rates of embryo initiation were compared in two species of Cryptantha (Boraginaceae) which differ greatly in their patterns of seed (nutlet) production. Cryptantha flava normally matures only one of the four ovules per ovary while C. flavoculata often matures all four. The general floral morphology and composition of insect floral visitors were found to be nearly identical in the two species, but C. flavoculata produces twice as much pollen per flower as C. flava. Despite this difference, the amount of pollen deposited on stigmas by pollinators is similar. This may be due to the larger stigmatic surface area in C. flava. In both species, the abortion of fertilized ovules, rather than insufficient amounts of pollen, appears to be the primary factor regulating the number of seeds per flower. The pollination ecology of these species is discussed in relation to current theories regarding the allocation of resources to the production of pollen and seeds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00378846
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Demographic consequences of drought in the herbaceous perennial Cryptantha flava: effects of density, associations with shrubs, and plant size (1996)
    Springer
    Oecologia 106 (1996), S. 144-152 
    Details
    ISSN: 1432-1939
    Keywords: Drought ; Competition ; Facilitation ; Demography ; Cryptantha flava
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The demographic consequences of a severe drought year were examined for two experimental plantings of the herbaceous desert perennial Cryptantha flava(Boraginaceae) in northeastern Utah, United States. A total of 6680 nutlets were planted individually or in clusters of four both under shrubs and in open microhabitats within two natural populations. Survival, growth, and flowering as a function of density and microhabitat were followed for 7 years, including 1 year when precipitation just before and during the growing season was 74.5% below normal. The design permitted assessment of how intraspecific density and shrub cover affect demographic response to drought. Mortality increased and flowering decreased dramatically during drought but neither varied with density or between shrub and open microhabitats. For plants growing under shrubs, survival (at Site 1) and growth (at Site 2) varied with shrub species. Average aboveground plant size also decreased during drought. Population size hierarchies were rearranged because larger plants lost leaf rosettes while many smaller plants grew. Density and microhabitat affected plant performance in non-drought years but more often at Site 1 than at Site 2. Individuals growing alone often were more likely to flower and/or produced more inflorescences when they did flower than did individuals growing with at least one other plant. However, for 2 years, survival rates at Site 1 were higher for plants growing in clumps than for single individuals. Shrubs also had mixed effects on plant performance. In some years, survival was higher under shrubs, but at Site 1 plants in the open often were more likely to flower and/or produced more inflorescences. Thus despite severe demographic consequences of drought, the study provided no evidence that intraspecific competition, interference by shrubs, or facilitation by shrubs increases under limited soil water.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00328593
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Ecological correlates of single-seededness in a woody tropical flora (1992)
    Springer
    Oecologia 90 (1992), S. 212-217 
    Details
    ISSN: 1432-1939
    Keywords: Seeds ; Fruits ; Single-seededness ; Dispersal agents ; Dispersal units
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A reduction in seed number per fruit is recognized as a common evolutionary trend among flowering plants. In order to evaluate the ecological role of single-seededness and its possible adaptive significance, we used van Roosmalen's (1985) descriptions of fruits for woody species in the Guianan flora to identify fruit and seed characters and dispersal syndromes associated with the single-seeded trait. We coded the following characters: seed number (one seed or more than one seed), fleshiness (dry or fleshy), dehiscence (dehiscent or indehiscent), dispersal syndrome, seed size (length), and fruit size (length). We ordered the data in a multi-dimensional contingency table and used maximum likelihood logistic regression to identify traits significantly correlated with single-seededness. Seed size and fruit size were treated as quantitative variables. Indehiscence and endozoochory are positively associated with single-seededness, with indehiscence contributing most to the best-fit model. Fruit size and seed size are also important with the probability of single-seededness generally increasing with seed size and decreasing with fruit size, although a (fruit size) x (seed size) interaction term is significant. Dry fruits are positively associated with single-seededness and dispersal by synzoochory or myrmecochory negatively associated when the full data set is examined, but neither parameter is significant in two models constructed to remove effects of phylogeny. A nested ANOVA revealed that most variation occurs below the family level for almost all of the traits considered, with the exception of the dry vs. fleshy trait for which there is no variation within genera. We argue that the strong association between indehiscence and single-seededness suggests selective advantages for single-seeded dispersal units but acknowledge that energetic trade-offs between seed number and seed size probably also occur. We suggest that the post-dispersal fates of seeds — especially those deposited in clumps by endozoochory — should be examined with the idea of identifying selective pressures on seed number per fruit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00317178
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    facet.materialart.
    Unknown
    A communal catalogue reveals Earth’s multiscale microbial diversity (2017)
    Nature Research
    In:  Nature, 551 (7681). pp. 457-463.
    Details
    Publication Date: 2020-02-06
    Description: Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity.
    Type: Article , PeerReviewed
    Format: text
    DOI: 10.1038/nature24621
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 6
    facet.materialart.
    Unknown
    Diversity of ageing across the tree of life (2014)
    Details
    Publication Date: 2022-05-26
    Description: Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature 505 (2014): 169-173, doi:10.1038/nature12789.
    Description: Evolution drives and is driven by demography. A genotype moulds its phenotype’s age-patterns of mortality and fertility in an environment; these two patterns in turn determine the genotype’s fitness in that environment. Hence, to understand the evolution of ageing, age-patterns of mortality and reproduction need to be compared for species across the tree of life. Yet few studies have done so and only for a limited range of taxa. Here we contrast standardised age patterns for 11 mammals, 12 other vertebrates, 10 invertebrates, 12 vascular plants, and a green alga. While it has been predicted that evolution should inevitably lead to increasing mortality and declining fertility with age after maturity, these species exhibit extraordinary variety, including increasing, constant, decreasing, humped and bowed trajectories for both long and short lived species. This diversity challenges theoreticians to develop broader perspectives on the evolution of ageing and empiricists to study the demography of more species.
    Description: JWV and AS acknowledge support from NIH grant PO1 AG-031719. HC acknowledges a Research Grant from the Alexander von Humboldt Foundation and Advanced Grant 322989 from the European Research Council. RSG acknowledges support from ARC DP110100727.
    Description: 2014-06-08
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: application/vnd.ms-excel
    Format: application/pdf
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...