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  • Betini, Gustavo S.  (5)
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  • 1
    In: Ecosphere, Wiley, Vol. 10, No. 8 ( 2019-08)
    Abstract: Although temperature is recognized as a major determinant of many ecological processes, it is still not clear whether temperature increase caused by climate change will strengthen or weaken species interactions. One hypothesis is that interactions will respond non‐monotonically to temperature because thermal performance curves, which determine the strength of these interactions, are also non‐monotonic. To evaluate this hypothesis, we developed a temperature‐dependent consumer–resource model and tested predictions from this model in large freshwater mesocosms populated with green algae ( Chlorella vulgaris ) and herbivorous zooplankton ( Daphnia magna ). We found both in the model simulations and empirical investigations that the suppressive effect of the consumer depended non‐monotonically on the temperature. As predicted by the model, Daphnia suppressed the algal maximum per capita growth rate at the temperature that maximized algal growth rate but had little effect on resource growth at either lower or higher temperatures. This finding could help explain why effects of temperature variation on species interaction are variable in the literature and suggests that predicting the effects of temperature on the strength of food web interactions requires knowledge of the thermal performance curves for multiple traits, for multiple species and over a range of temperatures.
    Type of Medium: Online Resource
    ISSN: 2150-8925 , 2150-8925
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 2572257-8
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  • 2
    Online Resource
    Online Resource
    The Royal Society ; 2017
    In:  Royal Society Open Science Vol. 4, No. 1 ( 2017-01), p. 160756-
    In: Royal Society Open Science, The Royal Society, Vol. 4, No. 1 ( 2017-01), p. 160756-
    Abstract: The use of multiple working hypotheses to gain strong inference is widely promoted as a means to enhance the effectiveness of scientific investigation. Only 21 of 100 randomly selected studies from the ecological and evolutionary literature tested more than one hypothesis and only eight tested more than two hypotheses. The surprising rarity of application of multiple working hypotheses suggests that this gap between theory and practice might reflect some fundamental issues. Here, we identify several intellectual and practical barriers that discourage us from using multiple hypotheses in our scientific investigation. While scientists have developed a number of ways to avoid biases, such as the use of double-blind controls, we suspect that few scientists are fully aware of the potential influence of cognitive bias on their decisions and they have not yet adopted many techniques available to overcome intellectual and practical barriers in order to improve scientific investigation.
    Type of Medium: Online Resource
    ISSN: 2054-5703
    Language: English
    Publisher: The Royal Society
    Publication Date: 2017
    detail.hit.zdb_id: 2787755-3
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  • 3
    Online Resource
    Online Resource
    Wiley ; 2017
    In:  Ecology Vol. 98, No. 4 ( 2017-04), p. 1163-1170
    In: Ecology, Wiley, Vol. 98, No. 4 ( 2017-04), p. 1163-1170
    Abstract: Spatial self‐organization can occur in many ecosystems with important effects on food web dynamics and the maintenance of biodiversity. The consumer–resource interaction is known to generate spatial patterning, but only a few empirical studies have investigated the effect of the consumer on resource distribution. Here we report results from a large aquatic mesocosm experiment used to investigate the effect of the consumer Daphnia magna on the distribution of its resource, the green algae Chlorella vulgaris . We maintained large tanks with capacity for 26 ,000 L with either algae or both algae and Daphnia in different temperature conditions. We found that the presence of D. magna inhibited spatial structure in algal distribution that arose as a consequence of increasing temperature. We conjecture that this homogenization effect might be caused by a combination of high mobility combined with high rates of algal consumption by Daphnia . Our study emphasizes the importance of both local constraints on growth and behavioral responses in either promoting or suppressing spatial self‐organization in natural populations.
    Type of Medium: Online Resource
    ISSN: 0012-9658 , 1939-9170
    URL: Issue
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 1797-8
    detail.hit.zdb_id: 2010140-5
    SSG: 12
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  • 4
    Online Resource
    Online Resource
    Wiley ; 2020
    In:  Journal of Animal Ecology Vol. 89, No. 12 ( 2020-12), p. 2777-2787
    In: Journal of Animal Ecology, Wiley, Vol. 89, No. 12 ( 2020-12), p. 2777-2787
    Abstract: Despite being widely used, habitat selection models are rarely reliable and informative when applied across different ecosystems or over time. One possible explanation is that habitat selection is context‐dependent due to variation in consumer density and/or resource availability. The goal of this paper is to provide a general theoretical perspective on the contributory mechanisms of consumer and resource density‐dependent habitat selection, as well as on our capacity to account for their effects. Towards this goal we revisit the ideal free distribution (IFD), where consumers are assumed to be omniscient, equally competitive and freely moving, and are hence expected to instantaneously distribute themselves across a heterogeneous landscape such that fitness is equalised across the population. Although these assumptions are clearly unrealistic to some degree, the simplicity of the structure in IFD provides a useful theoretical vantage point to help clarify our understanding of more complex spatial processes. Of equal importance, IFD assumptions are compatible with the assumptions underlying common habitat selection models. Here we show how a fitness‐maximising space use model, based on IFD, gives rise to resource and consumer density‐dependent shifts in consumer distribution, providing a mechanistic explanation for the context‐dependent outcomes often reported in habitat selection analysis. Our model suggests that adaptive shifts in consumer distribution patterns would be expected to lead to nonlinear and often non‐monotonic patterns of habitat selection. These results indicate that even under the simplest of assumptions about adaptive organismal behaviour, habitat selection strength should critically depend on system‐wide characteristics. Clarifying the impact of adaptive behavioural responses may be pivotal in making meaningful ecological inferences about observed patterns of habitat selection and allow reliable transferability of habitat selection predictions across time and space.
    Type of Medium: Online Resource
    ISSN: 0021-8790 , 1365-2656
    URL: Issue
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2006616-8
    SSG: 12
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  • 5
    In: Ecology and Evolution, Wiley, Vol. 10, No. 2 ( 2020-01), p. 756-762
    Abstract: Reduced body size and accelerated life cycle due to warming are considered major ecological responses to climate change with fitness costs at the individual level. Surprisingly, we know little about how relevant ecological factors can alter these life history trade‐offs and their consequences for individual fitness. Here, we show that food modulates temperature‐dependent effects on body size in the water flea Daphnia magna and interacts with temperature to affect life history parameters. We exposed 412 individuals to a factorial manipulation of food abundance and temperature, tracked each reproductive event, and took daily measurements of body size from each individual. High temperature caused a reduction in maximum body size in both food treatments, but this effect was mediated by food abundance, such that low food conditions resulted in a reduction of 20% in maximum body size, compared with a reduction of 4% under high food conditions. High temperature resulted in an accelerated life cycle, with pronounced fitness cost at low levels of food where only a few individuals produced a clutch. These results suggest that the mechanisms affecting the trade‐off between fast growth and final body size are food‐dependent, and that the combination of low levels of food and high temperature could potentially threaten viability of ectotherms.
    Type of Medium: Online Resource
    ISSN: 2045-7758 , 2045-7758
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2635675-2
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