Predator biomass and vegetation influence the coastal distribution of threespine stickleback morphotypes.
Casey L Yanos, Eeke P Haanstra, Fiona Colgan Carey, Sorsha A Passmore, Johan S Eklöf, Ulf Bergström, Joakim P Hansen, Michael C Fontaine, Martine E Maan, Britas Klemens Eriksson
Author Information
Casey L Yanos: Groningen Institute for Evolutionary Life-Sciences GELIFES University of Groningen Groningen The Netherlands. ORCID
Eeke P Haanstra: Groningen Institute for Evolutionary Life-Sciences GELIFES University of Groningen Groningen The Netherlands.
Fiona Colgan Carey: Groningen Institute for Evolutionary Life-Sciences GELIFES University of Groningen Groningen The Netherlands.
Sorsha A Passmore: Groningen Institute for Evolutionary Life-Sciences GELIFES University of Groningen Groningen The Netherlands.
Johan S Eklöf: Department of Ecology, Environment and Plant Sciences Stockholm University Stockholm Sweden. ORCID
Ulf Bergström: Department of Aquatic Resources Swedish University of Agricultural Sciences Uppsala Sweden.
Joakim P Hansen: Stockholm University Baltic Sea Centre Stockholm Sweden.
Michael C Fontaine: Groningen Institute for Evolutionary Life-Sciences GELIFES University of Groningen Groningen The Netherlands. ORCID
Martine E Maan: Groningen Institute for Evolutionary Life-Sciences GELIFES University of Groningen Groningen The Netherlands. ORCID
Britas Klemens Eriksson: Groningen Institute for Evolutionary Life-Sciences GELIFES University of Groningen Groningen The Netherlands. ORCID
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 () 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 ( and pike (). 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.
