Biotic and abiotic drivers of intraspecific trait variation within plant populations of three herbaceous plant species along a latitudinal gradient

Abstract

BackgroundThe importance of intraspecific trait variation (ITV) is increasingly acknowledged among plant ecologists. However, our understanding of what drives ITV between individual plants (ITVBI) at the population level is still limited. Contrasting theoretical hypotheses state that ITVBI can be either suppressed (stress-reduced plasticity hypothesis) or enhanced (stress-induced variability hypothesis) under high abiotic stress. Similarly, other hypotheses predict either suppressed (niche packing hypothesis) or enhanced ITVBI (individual variation hypothesis) under high niche packing in species rich communities. In this study we assess the relative effects of both abiotic and biotic niche effects on ITVBI of four functional traits (leaf area, specific leaf area, plant height and seed mass), for three herbaceous plant species across a 2300 km long gradient in Europe. The study species were the slow colonizing Anemone nemorosa, a species with intermediate colonization rates, Milium effusum, and the fast colonizing, non-native Impatiens glandulifera.ResultsClimatic stress consistently increased ITVBI across species and traits. Soil nutrient stress, on the other hand, reduced ITVBI for A. nemorosa and I. glandulifera, but had a reversed effect for M. effusum. We furthermore observed a reversed effect of high niche packing on ITVBI for the fast colonizing non-native I. glandulifera (increased ITVBI), as compared to the slow colonizing native A. nemorosa and M. effusum (reduced ITVBI). Additionally, ITVBI in the fast colonizing species tended to be highest for the vegetative traits plant height and leaf area, but lowest for the measured generative trait seed mass.ConclusionsThis study shows that stress can both reduce and increase ITVBI, seemingly supporting both the stress-reduced plasticity and stress-induced variability hypotheses. Similarly, niche packing effects on ITVBI supported both the niche packing hypothesis and the individual variation hypothesis. These results clearly illustrates the importance of simultaneously evaluating both abiotic and biotic factors on ITVBI. This study adds to the growing realization that within-population trait variation should not be ignored and can provide valuable ecological insights.Electronic supplementary materialThe online version of this article (10.1186/s12898-017-0151-y) contains supplementary material, which is available to authorized users.

Light and warming drive forest understorey community development in different environments

“…Plant community theories predict that increasing light availability can modulate the herb layer development trajectory in sites where N and P are less limiting to plant growth (Grime, ; Jabot & Pottier, ; Tilman, ), which has been observed in temperate forest understories (Baeten et al, ; Hedwall & Brunet, ). Second, this increase in light availability can accelerate effects of climate warming so that herbaceous communities come to resemble those of warmth‐adapted communities (Bjorkman et al, ; De Frenne et al, ; Helsen et al, ; Henn et al, ; Hoeppner & Dukes, ). The increasing light availability may also alter soil microbial communities and enhance their activity which can release nutrients for plants (Ma et al, ; Ni et al, ).…”

Geographic scale and disturbance influence intraspecific trait variability in leaves and roots of North American understorey plants

“…The crucial question that emerges is, therefore, when and why is ITV more important? Previous studies have suggested that ITV is a mechanism by which plant species respond to local spatial resource heterogeneity (Valladares, Gianoli, & Gómez, 2007) and is related to environmental variation across the species' range (Helsen et al, 2017). Intraspecific trait variability may be particularly important in low diversity ecosystems where reduced competition could allow individuals of the same species to occupy a larger trait space (Freschet, Bellingham, Lyver, Bonner, & Wardle, 2013;Silvertown & Charlesworth, 2009;Violle et al, 2012).…”

Variation in root secondary metabolites is shaped by past climatic conditions

“…Studies of inter- and intraspecific plant trait variation across environmental gradients, such as those related to latitude and elevation, have been receiving increasing attention (Anstett et al, 2018; Hahn et al, 2018; Pellissier, Roger, Bilat, & Rasmann, 2014; Woods et al, 2012). Although such studies are beyond doubt important and useful to test classic theories predicting herbivore defence (Anstett et al, 2015; Moles et al, 2011) and resource allocation patterns (Helsen et al, 2017; Kooyers, Greenlee, Colicchio, Oh, & Blackman, 2015), they also have to cope with the difficulty of potentially hidden dynamics along gradients. Changes in abiotic and biotic factors may be correlated and interconnected to changes in geographical location, which complicates the disentangling of environmental impacts on plant traits (Hahn et al, 2018; Johnson & Rasmann, 2011).…”