Chronic warming, not heatwaves, predicts tropical fish colonization in the Mediterranean
- 1Museo Nacional de Ciencias Naturales (CSIC)
Abstract
The opening of the Suez Canal abruptly reconnected the Red Sea and the Mediterranean Sea, collapsing a geological barrier that had separated their biotas for millions of years. This exchange offers a natural experiment to determine whether tropical species' spread at their cold-edge range is driven by acute thermal shocks (marine heatwaves) or by progressive easing of physiological constraints under sustained warming. We analyzed 1,059 first-arrival time series for 75 non-indigenous fish species across the Mediterranean, explicitly accounting for progressive salinification, oceanographic connectivity, and historical canal enlargement. Our models demonstrate that colonization dynamics are overwhelmingly dominated by ecological momentum-the time-dependent geographic spread of populations-and facilitated by chronic background warming. Marine heatwaves explain negligible variance and show no detectable effect on colonization success. Instead, warming operates as a stage-dependent continuous climatic facilitator, accelerating post-establishment expansion, rather than triggering introductions. Thus, this shift toward warm-adapted communities is governed by chronic warming, with the Suez Canal triggering the reorganization of Mediterranean biogeography.
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BibTeX
@misc{chaikin2026chronic,
title = {{Chronic warming, not heatwaves, predicts tropical fish colonization in the Mediterranean}},
author = {S. Chaikin and G. Vagenas and M. Matias and M. Galanidi and A. Zenetos and M. Araujo},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.03.749106},
url = {https://www.biorxiv.org/content/10.64898/2026.09.03.749106v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Chronic warming, not heatwaves, predicts tropical fish colonization in the Mediterranean
AU - S. Chaikin
AU - G. Vagenas
AU - M. Matias
AU - M. Galanidi
AU - A. Zenetos
AU - M. Araujo
PY - 2026
DA - 2026/09/03
PB - bioRxiv
DO - 10.64898/2026.09.03.749106
UR - https://www.biorxiv.org/content/10.64898/2026.09.03.749106v1
AB - The opening of the Suez Canal abruptly reconnected the Red Sea and the Mediterranean Sea, collapsing a geological barrier that had separated their biotas for millions of years. This exchange offers a natural experiment to determine whether tropical species' spread at their cold-edge range is driven by acute thermal shocks (marine heatwaves) or by progressive easing of physiological constraints under sustained warming. We analyzed 1,059 first-arrival time series for 75 non-indigenous fish species across the Mediterranean, explicitly accounting for progressive salinification, oceanographic connectivity, and historical canal enlargement. Our models demonstrate that colonization dynamics are overwhelmingly dominated by ecological momentum-the time-dependent geographic spread of populations-and facilitated by chronic background warming. Marine heatwaves explain negligible variance and show no detectable effect on colonization success. Instead, warming operates as a stage-dependent continuous climatic facilitator, accelerating post-establishment expansion, rather than triggering introductions. Thus, this shift toward warm-adapted communities is governed by chronic warming, with the Suez Canal triggering the reorganization of Mediterranean biogeography.
ER -