Will shrinking body size and increasing species diversity of crustaceans follow the warming of the Arctic littoral?

• Published in: Ecology and evolution Vol. 10; no. 19; pp. 10305 - 10313
• Main Authors: Węsławski, Jan M., Legeżyńska, Joanna, Włodarska‐Kowalczuk, Maria
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.10.2020; John Wiley and Sons Inc; Wiley
• Subjects: Arctic; Biodiversity; Body size; Coasts; Cold; competition; Crustaceans; Females; Geographical distribution; global warming; Hypotheses; Incubation; Life span; Littoral environments; Polar environments; Population; Shellfish; size; Size effects; species distribution; Species diversity; Arctic region; competition; biodiversity; global warming; size; species distribution; Arctic
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.6780

Over thirty species of littoral marine Gammaridea occur along the coasts of the North Atlantic. From one to several species can coexist in a single region. There is an evident, inverse relationship between egg incubation time and temperature (from 14 to >120 days) and consequent trends in the size of the animals on reaching maturity (from 5 mm in warmer waters to 30 mm in the coldest ones) and in lifespan (from <6 months to >5 years). Littoral gammarids are a good example of the shrinking size effect of increasing temperatures and size‐related species diversity. In large species, the annual cohorts of the population (3–5 annual size groups) functionally replace the adults of smaller species. The ongoing warming of the European Arctic seas may extend the distribution limits of boreal species so that more Gammarus species may appear on northern coasts hitherto occupied by just one or at most two species. Warming of the arctic shortens the long life cycles of large local amphipod littoral crustaceans. Faster development and maturity at smaller size opens space for competing small species that were not able to coexist with the large ones.