Higher spring temperatures increase food scarcity and limit the current and future distributions of crossbills

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  • Eduardo T. Mezquida, Autonomous Univ Madrid, Autonomous University of Madrid, Dept Ecol, Fac Sci
  • ,
  • Jens-Christian Svenning
  • Ron W. Summers, North Scotland Reg Off, Royal Soc Protect Birds, Ctr Conservat Sci
  • ,
  • Craig W. Benkman, Univ Wyoming, University of Wyoming, Dept Zool & Physiol

Aim: Understanding how climate affects species distributions remains a major challenge, with the relative importance of direct physiological effects versus biotic interactions still poorly understood. We focus on three species of resource specialists (crossbill Loxia finches) to assess the role of climate in determining the seasonal availability of their food, the importance of climate and the occurrence of their food plants for explaining their current distributions, and to predict changes in their distributions under future climate change scenarios.

Location: Europe.

Methods: We used datasets on the timing of seed fall in European Scots pine Pinus sylvestris forests (where different crossbill species occur) to estimate seed fall phenology and climate data to determine its influence on spatial and temporal variation in the timing of seed fall to provide a link between climate and seed scarcity for crossbills. We used large-scale datasets on crossbill distribution, cover of the conifers relied on by the three crossbill species and climate variables associated with timing of seed fall, to assess their relative importance for predicting crossbill distributions. We used species distribution modelling to predict changes in their distributions under climate change projections for 2070.

Results: We found that seed fall occurred 1.5-2 months earlier in southern Europe than in Sweden and Scotland and was associated with variation in spring maximum temperatures and precipitation. These climate variables and area covered with conifers relied on by the crossbills explained much of their observed distributions. Projections under global change scenarios revealed reductions in potential crossbill distributions, especially for parrot crossbills.

Main conclusions: Ranges of resource specialists are directly influenced by the presence of their food plants, with climate conditions further affecting resource availability and the window of food scarcity indirectly. Future distributions will be determined by tree responses to changing climatic conditions and the impact of climate on seed fall phenology.

Original languageEnglish
JournalDiversity and Distributions
Pages (from-to)473-484
Number of pages12
Publication statusPublished - Apr 2018

    Research areas

  • biotic interactions, European crossbills, food plants, global change, Loxia, range shift, species distribution, RECENT CLIMATE-CHANGE, SPECIES RANGE LIMITS, BIOTIC INTERACTIONS, PINUS-SYLVESTRIS, GLOBAL CHANGE, PLANT PHENOLOGY, SEED PREDATION, BILL STRUCTURE, DIVERSITY, EVOLUTION

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ID: 125588615