Different gardens, different results: native and introduced populations exhibit contrasting phenotypes across common gardens

Abstract

Invasive plants may respond through adaptive evolution and/or phenotypic plasticity to new environmental conditions where they are introduced. Although many studies have focused on evolution of invaders particularly in the context of testing the evolution of increased competitive ability (EICA) hypothesis, few consistent patterns have emerged. Many tests of the EICA hypothesis have been performed in only one environment; such assessments may be misleading if plants that perform one way at a particular site respond differently across sites. Single common garden tests ignore the potential for important contributions of both genetic and environmental factors to affect plant phenotype. Using a widespread invader in North America, Cynoglossum officinale, we established reciprocal common gardens in the native range (Europe) and introduced range (North America) to assess genetically based differences in size, fecundity, flowering phenology and threshold flowering size between native and introduced genotypes as well as the magnitude of plasticity in these traits. In addition, we grew plants at three nutrient levels in a pot experiment in one garden to test for plasticity across a different set of conditions. We did not find significant genetically based differences between native and introduced populations in the traits we measured; in our experiments, introduced populations of C. officinale were larger and more fecund, but only in common garden experiments in the native range. We found substantial population-level plasticity for size, fecundity and date of first flowering, with plants performing better in a garden in Germany than in Montana. Differentiation of native populations in the magnitude of plasticity was much stronger than that of introduced populations, suggesting an important role for founder effects. We did not detect evidence of an evolutionary change in threshold flowering size. Our study demonstrates that detecting genetically based differences in traits may require measuring plant responses to more than one environment.

Phenotypic plasticity and performance of Taraxacum officinale (dandelion) in habitats of contrasting environmental heterogeneity

“…More related to our research question, results show that plants from USA, where rainfall variation during the growth season was greater, exhibited greater plasticity to water shortage in photosynthetic performance and flowering time than plants from Chile. This was true under experimental temperatures that resembled both early-and late-season conditions, thus avoiding misleading interpretations of single common garden tests (Williams et al 2008). These results agree with earlier studies (Cook and Johnson 1968;van Kleunen and Fischer 2001;Gianoli 2004;Gianoli and González-Teuber 2005) and theoretical expectations (Bradshaw and Hardwick 1989;Alpert and Simms 2002) of a positive association between the magnitude of phenotypic plasticity and the degree of environmental heterogeneity of the habitat.…”

“…Invasive plant species spread beyond their original range, successfully colonizing diverse environments (Rejmanek et al 2005). The relative importance of phenotypic plasticity and ecotypic differentiation in explaining their ample ecological breadth has been recently addressed (Sexton et al 2002;Parker et al 2003;Maron et al 2004;Geng et al 2007;Maron et al 2007;Williams et al 2008). A likely scenario for plant invasion is that plastic responses grant initial survival in novel habitats, further allowing naturalization (Sexton et al 2002).…”

Do exotic plants lose resistance to pathogenic soil biota from their native range? A test with Solidago gigantea

“…This variation is likely due in part to the particular herbivore tested (Joshi and Vrieling 2005;Schaffner et al 2011), equating growth to competitive ability (Ridenour et al 2008), under-sampling population and geographical variation within species across its ranges (Bossdorf et al 2005), and substantially different responses of genotypes among different sites within a range (Maron et al 2004;Williams et al 2008). Therefore, we should expect similar conditionality and variation in parallel studies of the evolutionary response of populations to soil biota.…”

La restauración ecológica clásica y los retos de la actualidad: La migración asistida como estrategia de adaptación al cambio climático

“…La ocurrencia de eventos climáticos extremos puede incrementar la presión de selección en la supervivencia más que las condiciones climáticas promedio (Jentsch & Beierkuhnlein, 2008), por lo que se recomienda una evaluación experimental de la tolerancia de las especies de interés a las condiciones climáticas esperadas (Kreyling et al, 2011). Este tipo de evaluación podría hacerse, por ejemplo, por medio de experimentos de jardín común, donde individuos de diferentes poblaciones de una especie están en las mismas condiciones ambientales para determinar su desempeño bajo determinados factores (Williams, Auge & Maron, 2008), esto puede ayudar en el proceso de selección de fuentes de propágulos para proyectos de restauración (Bower, Bradley, Clair & Erickson, 2014).…”