Multidimensional trait variability in a widespread, Paleoarctic macrophyte: functional, spectral and genetic drivers

Abstract

Understanding how environmental conditions and plant functional variation are mutually related is critical to improving our comprehension of plant adaptations. In this context, our knowledge of the interlinks between plant functional, spectral and genetic traits and environmental filters is still very limited, especially for wetland species. To gain new insights on this topic, a multidimensional dataset, centred on the widespread macrophyte species Nuphar lutea, was assembled by collecting data on functional traits (including spectral traits), genetic metrics and environmental determinants from 28 plots spanning north‐central Italy. A strong environmental filter acts on all traits (morphological, biochemical, spectral and the genetic diversity metrics) resulting in significant local control over trait patterns, exemplified by the discrimination value of water electrical conductivity. This is further reinforced by the key contribution of sediment variables in explaining traits variation. Site‐specific environmental conditions were reflected in different patterns of genetic diversity, suggesting a long‐term effect of environmental filters on genotypes as well. High water conductivity – in our study sites indicative of long‐term hydrogeological settings – is linked to more acquisitive behaviour in N. lutea and a progressive reduction in its genetic diversity, while high nutrients availability in sediments promotes higher leaf traits performance. This study better explores how high variability in leaf traits reinforces current genetic and mechanistic knowledge about competitive strategies in the key aquatic plant N. lutea, by testing the effectiveness of a novel integrative approach to assess multiple sources of plant functional variation.

Ecological and functional niches comparison reveals differentiated resource-use strategies and ecological thresholds in four key floating-leaved macrophytes

“…Thus, the functional plasticity of this species is triggered by changes in the environment, allowing it to increase its performance under favorable conditions (Kordyum & Klimenko 2013; Nowak et al 2015), or to adapt to a more conservative strategy under harsh conditions (Richards et al 2011; Klok & van der Velde 2017). However, although N. lutea populations can occupy a wide range of environmental conditions, with a range of electrical conductivity of nearly 400 µS cm −1 and nitrate concentration as high as 9.5 mg L −1 (Dalla Vecchia et al 2024), based on our results, it has not yet established under extreme environmental conditions, represented by very high conductivity and nutrients content where only N. nucifera was found.…”

“…Besides, the use of leaf economics spectrum traits is widely consolidated in the literature, which would allow our results to be more comparable with previous studies (Pierce et al 2012; Pan et al 2019). Finally, variability of these traits in response to variation in water and sediment parameters was already observed in N. lutea (Dalla Vecchia & Bolpagni 2022; Dalla Vecchia et al 2024). In each population, eight young, i.e., fully expanded leaves with no sign of damage, or illness, or herbivory were collected from eight distinct plants, paying attention to collect the full petiole length.…”

“…This confirms its reputation as a top-competitor species in aquatic environments (Bornette et al 2008; Paillisson & Marion 2011). Previous studies have shown that N. lutea is able to modulate its response and resource-use strategies to variable conditions and can inhabit even highly eutrophic environments (Dalla Vecchia & Bolpagni, 2022; Dalla Vecchia et al 2024). Thus, the functional plasticity of this species is triggered by changes in the environment, allowing it to increase its performance under favorable conditions (Kordyum & Klimenko 2013; Nowak et al 2015), or to adapt to a more conservative strategy under harsh conditions (Richards et al 2011; Klok & van der Velde 2017).…”

“…It is hence of great interest to evaluate the degree of niche uniqueness – namely, the proportion of a species’ niche not shared with others – to quantify differences among species and catch functional or ecological specialization. Previous studies on nymphaeids have shown great variability in traits in response to environmental (trophic) gradients (Dalla Vecchia & Bolpagni 2022; Castellani et al 2023; Dalla Vecchia et al 2024). The contrasting results regarding their performance and resource-use strategies under different eutrophic conditions stress the need to combine functional and ecological information (Pełechaty 2007).…”