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- Toräng, Per, et al.
(författare)
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Linking environmental and demographic data to predict future population viability of a perennial herb
- 2010
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 163:1, s. 99-109
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in stochastic demography provide tools to examine the importance of random and periodic variation in vital rates for population dynamics. In this study, we explore with simulations the effect of disturbance regime on population dynamics and viability. We collected 7 years of demographic data in three populations of the perennial herb Primula farinosa, and used these data to examine how variation in vital rates affected population viability parameters (stochastic growth rate, lambda(S)), and how vital rates were related to weather conditions. Elasticity analysis indicated that the stochastic growth rate was very sensitive to changes in regeneration, quantified as the production, survival, and germination of seeds. In one of the study years, all seedlings and mature plants in the demography plots died. This extinction coincided with the driest summer during the study period. Simulations suggested that a future increase in the frequency of high-mortality years due to climate change would result in reduced population growth rate, and an increased importance of survival in the seed bank for population viability. The results illustrate how the limited demographic data typically available for many natural systems can be used in simulation models to assess how environmental change will affect population viability.
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| 2. |
- Vanhoenacker, Didrik, et al.
(författare)
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Morph-specific selection on floral traits in a polymorphic plant
- 2010
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Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 23:6, s. 1251-1260
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Tidskriftsartikel (refereegranskat)abstract
- Correlations between phenotypic traits are common in many organisms, but the relative importance of nonadaptive mechanisms and selection for the evolution and maintenance of such correlations are poorly understood. In polymorphic species, morphs may evolve quantitative differences in additional characters as a result of morph-specific selection. The perennial rosette herb Primula farinosa is polymorphic for scape length. The short-scaped morph is less damaged by grazers and seed predators but is more strongly pollen limited than the long-scaped morph. We examined whether morph-specific differences in biotic interactions are associated with differences in selection on two other traits affecting floral display (number of flowers and petal size) and on one trait likely to affect pollination efficiency (corolla tube width) in three P. farinosa populations. Differences in selection between morphs were detected in one population. In this population, selection for more flowers and larger petals was stronger in the short-scaped than in the long-scaped morph, and although there was selection for narrower corolla tubes in the short-scaped morph, no statistically significant selection on corolla tube width could be detected in the long-scaped morph. In the study populations, the short-scaped morph produced more and larger flowers and wider corolla tubes. Current morph-specific selection was thus only partly consistent with trait differences between morphs. The results provide evidence of morph-specific selection on traits associated with floral display and pollination efficiency, respectively.
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