The effect of trait‐based diversity on productivity results mainly from intraspecific trait variability in the macrophyte community

Abstract

Trait‐based methods are key to understanding the biodiversity–productivity relationship (BPR) of macrophyte communities. Community‐weighted mean traits (i.e., community trait structure) have been proven to have more influence on macrophyte community productivity than species richness. However, the underlying mechanism by which community trait structure variation affects macrophyte community productivity along an environmental gradient is still not well understood. A mesocosm experiment was used to investigate how community trait structure shapes macrophyte community productivity along the water depth gradient. Three submerged macrophyte species (Myriophyllum spicatum, Vallisneria natans and Potamogeton malaianus) were assembled into all possible combinations (one, two and three species per community) at three different water depths (1, 2.5 and 4 m). We fitted the relationships between community‐weighted mean traits and community productivity, and between species richness and community productivity as a comparison. We compared functional traits under different water depths and species composition at the species and community levels and disentangled the community trait structure into species turnover and intraspecific trait variability effects. The results showed that community trait structure had various influences on macrophyte community productivity, which was based on traits per se. However, species richness had a non‐significant impact on macrophyte community productivity. Water depth had a significant impact on most traits of the three species at the species level, whereas both water depth and species composition had significant impacts on community trait structure which was mainly affected by intraspecific trait variability along the water depth gradient. Our findings highlight the importance of considering intraspecific trait variability and species turnover under water depth gradients to understand the relationship between trait‐based biodiversity and productivity.

How does trait variance partitioning help us to understand plant community assembly? The example of pond communities in the Kerguelen Islands

“…The SEM approach allowed us to demonstrate that all traits considered except the LDMC had direct or indirect effects on individual performance. This observation is especially important, as the relationships between traits can influence individual performance (Pywell et al., 2003; Engbersen et al., 2022), in particular in macrophyte species (Fu et al., 2014; Ma et al., 2022b). Our findings support the current view in functional ecology of the relevance of multitrait approaches in which trait relationships are taken into account (Albert et al., 2010a; Blonder et al., 2014; Bittebiere et al., 2019; Gustafsson & Norkko, 2019).…”

“…Two decades ago, functional approaches emerged that allowed us to rebuild community ecology and establish general principles regarding assembly mechanisms (Calow, 1987; McGill et al., 2006). Since then, studies based on functional traits (morphological, physiological, and phenological characteristics that directly or indirectly impact individual performance through growth, reproduction, or survival) have been conducted in terrestrial (e.g., Garnier et al., 2001; Violle et al., 2007; Albert et al., 2010a), and aquatic plant communities (Yang et al., 2004; Fu et al., 2013, 2014; Luo et al., 2016; Su et al., 2019; Zhang et al., 2019; Chmara et al., 2021; Ma et al., 2022a, 2022b). Functional approaches have revealed that marked trait variation occurs in the field at inter‐ and intraspecific levels in response to a range of biological processes operating at different spatial and temporal scales, ultimately leading to species coexistence (Messier et al., 2010; Albert et al., 2010a; Taudiere & Violle, 2016).…”

Temperature explains intraspecific functional trait variation in Phragmites australis more effectively than soil properties

“…Numerous empirical studies have elucidated the nature of trait variation and have shown systematic relationships between traits and climatic and/or soil properties (Wright et al, 2005;Cornwell and Ackerly, 2009;Simpson et al, 2016). However, the dominant theories and methods of trait-based community ecology mainly focus on the differences in functional traits between species (Roscher et al, 2018), whereas the important role of intraspecific trait variation has been neglected (Siefert et al, 2015;Ma et al, 2022). Species with a widespread distribution tend to have greater trait variability and high intraspecific variation; moreover, they show a continuous geographic gradient, especially across different latitudes, as a consequence of acclimation to a broad range of environmental conditions (Siefert et al, 2015;Ren et al, 2020).…”