| 1. |
- Alho, J. S., et al.
(författare)
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Allen's rule revisited : quantitative genetics of extremity length in the common frog along a latitudinal gradient
- 2011
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 24:1, s. 59-70
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Tidskriftsartikel (refereegranskat)abstract
- Ecogeographical rules linking climate to morphology have gained renewed interest because of climate change. Yet few studies have evaluated to what extent geographical trends ascribed to these rules have a genetic, rather than environmentally determined, basis. This applies especially to Allen's rule, which states that the relative extremity length decreases with increasing latitude. We studied leg length in the common frog (Rana temporaria) along a 1500 km latitudinal gradient utilizing wild and common garden data. In the wild, the body size-corrected femur and tibia lengths did not conform to Allen's rule but peaked at mid-latitudes. However, the ratio of femur to tibia length increased in the north, and the common garden data revealed a genetic cline consistent with Allen's rule in some trait and treatment combinations. While selection may have shortened the leg length in the north, the genetic trend seems to be partially masked by environmental effects.
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| 2. |
- Rogell, Björn, et al.
(författare)
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Strong divergence in trait means but not in plasticity across hatchery and wild populations of sea-run brown trout Salmo trutta
- 2012
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Ingår i: Molecular Ecology. - 0962-1083 .- 1365-294X. ; 21:12, s. 2963-2976
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Tidskriftsartikel (refereegranskat)abstract
- There is ample evidence that organisms adapt to their native environment when gene flow is restricted. However, evolution of plastic responses across discrete environments is less well examined. We studied divergence in means and plasticity across wild and hatchery populations of sea-run brown trout (Salmo trutta) in a common garden experiment with two rearing environments (hatchery and a nearly natural experimental stream). Since natural and hatchery environments differ, this arrangement provides an experiment in contemporary adaptation across the two environments. A QST - FST approach was used to investigate local adaptation in survival and growth over the first summer. We found evidence for divergent selection in survival in 1 year and in body length in both years and rearing environments. In general, the hatchery populations had higher survival and larger body size in both environments. QST in body size did not differ between the rearing environments, and constitutive divergence in the means was in all cases stronger than divergence in the plastic responses. These results suggest that in this system, constitutive changes in mean trait values are more important for local adaptation than increased plasticity. In addition, ex situ rearing conditions induce changes in trait means that are adaptive in the hatchery, but potentially harmful in the wild, suggesting that hatchery rearing is likely to be a suboptimal management strategy for trout populations facing selection in the stream environment.
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| 3. |
- Schmidt, Neele, et al.
(författare)
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Acclimatizing laboratory-reared hatchling cod (Gadus morhua) to salinity conditions in the Baltic Sea
- 2024
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Ingår i: Aquaculture. - : Elsevier. - 0044-8486 .- 1873-5622. ; 579
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Tidskriftsartikel (refereegranskat)abstract
- Decades of overfishing and unsustainable management, together with habitat degradation and eutrophication, depleted the cod (Gadus morhua) stocks in the Baltic Sea. Accompanying severe oxygen deficiency and decreased salinity in their spawning grounds restricted successful spawning today to the Bornholm basin, resulting in decreased recruitment. In order for the species to recover, several different measures are required and proposed, among others restocking. We therefore investigated the possibility of producing laboratory-reared cod larvae acclimatized to the current environment in the Baltic Sea. For this, cod were reared from newly fertilized eggs to non-feeding yolk-sac larvae, testing the effect of different salinity reduction treatments during early development on mortality, hatching success, and neutral buoyancy. The results show that a sudden ambient salinity decrease after hatching has no strong effect on survival or hatching (around 60% and 95%, respectively), while it decreased neutral buoyancy of larvae from 18 to minimum 12.5 psu. Lowest buoyancy was reached in treatments with a salinity change in the early egg stage. Gradual salinity decrease starting early in the egg stage yielded to significantly increased mortality and reduced hatching success, but also lowest buoyancy of 12 psu. We showed that a decrease of ambient salinity enables the production of yolk-sac cod larvae with reduced buoyancy, which are potentially better acclimatized to survive in current environmental conditions in the Baltic Sea.
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| 4. |
- Thulin, Carl-Gustaf, et al.
(författare)
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Differences in body mass, health status and genetic variation between insular and mainland brown hares (Lepus europaeus) in Sweden
- 2012
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Ingår i: European Journal of Wildlife Research. - : Springer Science and Business Media LLC. - 1612-4642 .- 1439-0574. ; 58:6, s. 897-907
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Tidskriftsartikel (refereegranskat)abstract
- Introduced populations can be affected by random processes such as genetic drift, deterministic processes given by the local environmental conditions and anthropogenic factors such as hunting and management. Geographically constrained populations are particularly exposed to these processes, and altogether, these factors may result in rapid differentiation from the ancestral populations. The introduced European brown hare (Lepus europaeus) population on the island Ven is isolated from the Swedish and Danish mainland. Undocumented observations suggest that the hares on the island have been increasingly diseased in recent years and also decreased in body size. To test the substance of these observations, as well as the potential for inbreeding depression in this geographically constrained population, a total of 321 hares from Ven and three reference populations on the Swedish mainland were analysed with respect to body mass, general health status and genetic variation. The results confirm that the hares on Ven have lower body mass than hares on the mainland, but there are no indications of health deficits. We argue that the difference in body mass primarily is an island effect of stress and/or nutritional shortage, possibly induced by high population density, anthropogenic selection regimes and absence of mammalian meso-predators. Further, the genetic data indicate that the insular population is substructured, and subadults from these two subpopulations differ in body mass. This apparent substructuring could be due to chance effects, but may also be related to assortative mating or presence of sustained populations with different ancestry.
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