Evolution and disappearance of sympatric Coregonus albula ina changing environment—A case study of the only remainingpopulation pair in Sweden
During the past 50 years, Fennoscandian populations of spring‐spawning Baltic cisco ( Coregonus albula ), sympatric to common autumn‐spawners, have declined or disappeared; for example, three out of four known spring‐spawning populations in Sweden are regarded as extinct. Over the same period, the c...
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Published in | Ecology and evolution Vol. 9; no. 22; p. 12727 |
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Main Author | |
Format | Journal Article |
Language | English |
Published |
2019
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Subjects | |
Online Access | Get full text |
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Summary: | During the past 50 years, Fennoscandian populations of spring‐spawning Baltic cisco
(
Coregonus albula ), sympatric to common autumn‐spawners, have declined or disappeared;
for example, three out of four known spring‐spawning populations in Sweden
are regarded as extinct. Over the same period, the climate has changed and populations
have been subject to other anthropogenic stressors. We compared historic
(1960s) and recent (1990–000s) morphological data from the still‐existent sympatric
cisco populations in Lake Fegen, Sweden. Phenotypic changes were found for
spring‐spawners making them more similar to the sympatric autumn‐spawners that
had remained virtually unchanged. Based on results for other salmoniform fishes,
a phenotypically plastic response to increased temperature during early development
appears unlikely. The recent material was also analyzed with microsatellite
markers; long‐term effective population size in spring‐spawners was estimated to
be about 20 times lower than autumn‐spawners, with signs of long‐term gene flow
in both directions and a recent genetic bottleneck in spring‐spawners. We suggest
the change toward a less distinct phenotype in spring‐spawners to reflect a recent
increase in gene flow from autumn‐spawners. Time since divergence was estimated
to only
c . 1,900 years (95% CI: 400–5,900), but still the Fegen populations represent
the most morphologically and genetically distinct sympatric populations studied.
Consequently, we hypothesize that less distinct population pairs can be even
younger and that spring‐spawning may have repeatedly evolved and disappeared in
several lakes since the end of the last glaciation, concurrent with changed environmental
conditions. |
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ISSN: | 2045-7758 2045-7758 |
DOI: | 10.1002/ece3.5745 |