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Research article2021Peer reviewedOpen access

Predator biomass and vegetation influence the coastal distribution of threespine stickleback morphotypes

Yanos, Casey L.; Haanstra, Eeke P.; Carey, Fiona Colgan; Passmore, Sorsha A.; Eklof, Johan S.; Bergstrom, Ulf; Hansen, Joakim P.; Fontaine, Michael C.; Maan, Martine E.; Eriksson, Britas Klemens


Intraspecific niche differentiation can contribute to population persistence in changing environments. Following declines in large predatory fish, eutrophication, and climate change, there has been a major increase in the abundance of threespine stickleback (Gasterosteus aculeatus) in the Baltic Sea. Two morphotype groups with different levels of body armor-completely plated and incompletely plated-are common in coastal Baltic Sea habitats. The morphotypes are similar in shape, size, and other morphological characteristics and live as one apparently intermixed population. Variation in resource use between the groups could indicate a degree of niche segregation that could aid population persistence in the face of further environmental change. To assess whether morphotypes exhibit niche segregation associated with resource and/or habitat exploitation and predator avoidance, we conducted a field survey of stickleback morphotypes, and biotic and abiotic ecosystem structure, in two habitat types within shallow coastal bays in the Baltic Sea: deeper central waters and shallow near-shore waters. In the deeper waters, the proportion of completely plated stickleback was greater in habitats with greater biomass of two piscivorous fish: perch (Perca fluviatilis) and pike (Esox lucius). In the shallow waters, the proportion of completely plated stickleback was greater in habitats with greater coverage of habitat-forming vegetation. Our results suggest niche segregation between morphotypes, which may contribute to the continued success of stickleback in coastal Baltic Sea habitats.


ecosystem perturbation; ecotypic divergence; habitat specialization; intraspecific variation; stickleback

Published in

Ecology and Evolution
2021, Volume: 11, number: 18, pages: 12485-12496
Publisher: WILEY

    Associated SLU-program

    Coastal and sea areas

    Sustainable Development Goals

    Conserve and sustainably use the oceans, seas and marine resources for sustainable development

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