Evol Ecol Res 12: 929-947 (2010)     Full PDF if your library subscribes.

Sympatric diversification as influenced by ecological opportunity and historical contingency in a young species lineage of whitefish

Anna Siwertsson1, Rune Knudsen1, Kimmo K. Kahilainen2,3, Kim Præbel1, Raul Primicerio1 and Per-Arne Amundsen1

1Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, Tromsø, Norway,  2Department of Environmental Sciences, University of Helsinki, Helsinki, Finland and  3Kilpisjärvi Biological Station, University of Helsinki, Kilpisjärvi, Finland

Correspondence: A. Siwertsson, Department of Arctic and Marine Biology, Faculty of Biosciences, Fisheries and Economics, University of Tromsø, N-9037 Tromsø, Norway.
e-mail: anna.siwertsson@uit.no


Background: In adaptive radiations, ecological opportunity (i.e. niche availability) is considered to be an important driver to increase phenotypic variation, but diversity may also be constrained by historical factors related to colonization events.

Question: How do ecological opportunity and post-glacial colonization history affect the phenotypic diversity in a young species lineage?

Data: We quantified phenotypic diversity by the number of co-existing morphs and a heritable morphological trait (gill raker number) in 39 European whitefish (Coregonus lavaretus) populations. Level of diversity was compared within and between three sub-arctic watercourses, and explored in relation to ecological opportunity (habitat availability and lake productivity) and colonization history (lake elevation and position).

Results: We found three main distribution patterns of gill raker number: unimodal (approximate range 20–30), bimodal (20–30 vs. 30–40), and trimodal (15–20 vs. 20–30 vs. 30–40), representing monomorphic, dimorphic, and trimorphic populations respectively. In addition, a pattern intermediate to the monomorphic and dimorphic populations was recorded in all watercourses. Polymorphism increased from west to east among watercourses, which can mainly be explained by post-glacial colonization history. Higher diversity was also observed in downstream sites within each watercourse, and increased with lake size and productivity.

Conclusion: Our findings confirm that both ecological opportunity and historical constraints related to post-glacial colonization influence phenotypic patterns in a diverging lineage.

Keywords: Fennoscandia, phenotypic divergence, post-glacial fish, salmonid, speciation continuum.

IF you are connected using the IP of a subscribing institution (library, laboratory, etc.)
or through its VPN.


        © 2010 Anna Siwertsson. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

       Subscribing institutions/libraries may grant individuals the privilege of making a single copy of an EER article for non-commercial educational or non-commercial research purposes. Subscribing institutions/libraries may also use articles for non-commercial educational purposes by making any number of copies for course packs or course reserve collections. Subscribing institutions/libraries may also loan single copies of articles to non-commercial libraries for educational purposes.

       All copies of abstracts and articles must preserve their copyright notice without modification.