Philipp Laeseke, Brezo D.-C. Martínez, Kai Bischof
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引用次数: 0
Abstract
Aim
Climate change has profound effects on species' distributions, and it is crucial to understand how well physiological limits correspond to distribution patterns to provide realistic estimations of future range shifts and/or extinctions. Seaweeds are foundation species of global coastal ecosystems, and sea surface temperature is a main predictor to explain their distributions and redistributions under global warming. We here test the hypothesis that, in contrast to other marine ectotherms, physiological knowledge of temperature niches is a weak predictor for seaweed distributions.
Location
Global.
Time Period
Present (1984–2019).
Taxa
Seaweeds.
Methods
We analysed the predictive power of physiological temperature limits to predict real-world distributions in 126 globally distributed seaweed species with linear and generalized linear mixed models.
Results
In 72% of the species, there was a difference of ≥|2|°C between the physiological and the realized thermal limits. Both, thermal underfilling (distributional thermal limits narrower than the physiological limits) and overfilling (distributional thermal limits wider than the physiological limits) were present. Thus, in only 28% of the species the physiological limits corresponded to the distributional limits. While heat-tolerance is a significant predictor for upper distributional temperature limits, we found no relationship between cold-tolerance and lower distributional temperature limits and the latter two seem to be independent.
Main Conclusions
Physiological thermal limits have limited predictive power for seaweed distributions and deviations may be large. Especially cold-tolerances are a weak predictor, and forecasting of migrations under changing global conditions (e.g. towards the poles) will need special attention. This indicates that responses towards climate change might be highly variable between seaweed species and difficult to predict. Further, nearly 60% of the investigated species had populations which are close to or beyond their reported upper survival limits and are thus probably under threat of eradication by elevation of sea surface temperature.
期刊介绍:
Diversity and Distributions is a journal of conservation biogeography. We publish papers that deal with the application of biogeographical principles, theories, and analyses (being those concerned with the distributional dynamics of taxa and assemblages) to problems concerning the conservation of biodiversity. We no longer consider papers the sole aim of which is to describe or analyze patterns of biodiversity or to elucidate processes that generate biodiversity.