Seed source regions drive fitness differences in invasive macrophytes

Abstract

Premise Worldwide, ecosystems are threatened by global changes, including biological invasions. Invasive species arriving in novel environments experience new climatic conditions that can affect their successful establishment. Determining the response of functional traits and fitness components of invasive populations from contrasting environments can provide a useful framework to assess species responses to climate change and the variability of these responses among source populations. Much research on macrophytes has focused on establishment from clonal fragments; however, colonization from sexual propagules has rarely been studied. Our objective was to compare trait responses of plants generated from sexual propagules sourced from three climatic regions but grown under common environmental conditions, using L. peploides subsp. montevidensis as a model taxon. Methods We grew seedlings to reproductive stage in experimental mesocosms under a mediterranean California (MCA) climate from seeds collected in oceanic France (OFR), mediterranean France (MFR), and MCA. Results Seed source region was a major factor influencing differences among invasive plants recruiting from sexual propagules of L. peploides subsp. montevidensis. Trait responses of young individual recruits from MCA and OFR, sourced from geographically distant and climatically distinct source regions, were the most different. The MCA individuals accumulated more biomass, flowered earlier, and had higher leaf N concentrations than the OFR plants. Those from MFR had intermediate profiles. Conclusions By showing that the closer a seedling is from its parental climate, the better it performs, this study provides new insights to the understanding of colonization of invasive plant species and informs its management under novel and changing environmental conditions.

Variation of thermal plasticity for functional traits between populations of an invasive aquatic plant from two climatic regions

“…At 30 °C, the three populations originating from the Mediterranean region allocated more energy to biomass in general, and to the production of lateral shoots rather than to apical growth. These results are congruent with available literature (Rejmankova, 1992), and with a mesocosm experiment conducted in California (Gillard et al, 2020). Indeed, Gillard et al (2020) established that a higher climatic similarity in the source and invaded regions greatly assists the establishment and performance of L. peploides.…”

“…These results are congruent with available literature (Rejmankova, 1992), and with a mesocosm experiment conducted in California (Gillard et al, 2020). Indeed, Gillard et al (2020) established that a higher climatic similarity in the source and invaded regions greatly assists the establishment and performance of L. peploides. Overall, we found that Mediterranean populations of L. peploides performed significantly better at 30 °C than those from Oceanic populations.…”

“…As a result, examining functional traits of invasive populations provides a useful framework for the assessment of their responses to future climate change. As local conditions are strong drivers of phenotypic plasticity (King et al, 2018), the responses of geographically separated populations collected from contrasted climatic conditions would provide valuable comparisons of their potential differences (Sultan & Spencer, 2002;Drenovsky et al, 2012;Gillard et al, 2020), in turn improving information for making predictions of future geographic expansion.…”

A framework to integrate innovations in invasion science for proactive management

“…This and other reanalysis products, whose integrated frameworks mitigate issues of model and geographic bias ubiquitous to individual earth system models, remote sensing, and interpolated observational products (e.g. WorldClim), have enabled new capability for understanding the spread of IAS worldwide (Atala et al ., 2019; Gillard et al ., 2020).…”