Earlier onset of flowering and increased reproductive allocation of an annual invasive plant in the north of its novel range Number of Authors: 112020 (English)In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 126, no 6, p. 1005-1016Article in journal (Refereed) Published

Abstract [en]

• Background and Aims It remains unclear whether invasive species can maintain both high biomass and reproductive output across their invaded range. Along latitudinal gradients, allocation theory predicts that faster flowering onset at high latitudes results in maturation at smaller size and thus reduced reproductive output. For annual invasive plants, more favourable environmental conditions at low latitudes probably result in stronger competition of co-occurring species, potentially driving selection for higher investment in vegetative biomass, while harsher climatic conditions and associated reproductive uncertainty at higher latitudes could reduce selection for vegetative biomass and increased selection for high reproductive investment (stress-gradient hypothesis). Combined, these drivers could result in increased or constant reproductive allocation with increasing latitude.
• Methods We quantified life-history traits in the invasive annual plant Impatiens glandulifera along a latitudinal gradient in Europe. By growing two successive glasshouse generations, we assessed genetic differentiation in vegetative growth and reproductive output across six populations, and tested whether onset of flowering drives this divergence.
• Key Results Trait variation was mainly caused by genetic differentiation. As expected, flowering onset was progressively earlier in populations from higher latitudes. Plant height and vegetative biomass also decreased in populations from higher latitudes, as predicted by allocation theory, but their variation was independent of the variation in flowering onset. Reproductive output remained constant across latitudes, resulting in increased reproductive allocation towards higher latitudes, supporting the stress-gradient hypothesis. We also observed trait genetic differentiation among populations that was independent of latitude.
• Conclusions We show that an annual invasive plant evolved several life-history traits across its invaded range in ~150 years. The evolution of vegetative and reproductive traits seems unconstrained by evolution of flowering onset. This genetic decoupling between vegetative and reproductive traits possibly contributes to the invasion success of this species.

Place, publisher, year, edition, pages

2020. Vol. 126, no 6, p. 1005-1016

Keywords [en]

Allocation theory, common garden, flowering onset, Impatiens glandulifera, latitudinal gradient, life-history theory, maternal effects, phenology, reproductive investment, seed size, stress-gradient hypothesis

National Category

Biological Sciences

Identifiers

URN: urn:nbn:se:su:diva-188753DOI: 10.1093/aob/mcaa110ISI: 000591876700004PubMedID: 32582950OAI: oai:DiVA.org:su-188753DiVA, id: diva2:1519123

Available from: 2021-01-18 Created: 2021-01-18 Last updated: 2022-02-25Bibliographically approved

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Helsen, KennyCousins, Sara A. O.

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Helsen, KennyCousins, Sara A. O.

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Department of Physical Geography

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