Below‐ and aboveground traits explain local abundance, and regional, continental and global occurrence frequencies of grassland plants

Abstract

Plants vary widely in how common or rare they are, but whether commonness of species is associated with functional traits is still debated. This might partly be because commonness can be measured at different spatial scales, and because most studies focus solely on aboveground functional traits. We measured five root traits and seed mass on 241 central European grassland species, and extracted their specific leaf area, height, mycorrhizal status and bud-bank size from databases. Then we tested if trait values are associated with commonness at seven spatial scales, ranging from abundance in 16-m 2 grassland plots, via regional and European-wide occurrence frequencies, to worldwide naturalization success. At every spatial scale, commonness was associated with at least three traits. The traits explained the greatest proportions of variance for abundance in grassland plots (42%) and naturalization success (41%) and the least for occurrence frequencies in Europe and the Mediterranean (2%). Low root tissue density characterized common species at every scale, whereas other traits showed directional changes depending on the scale. We also found that many of the effects had significant non-linear effects, in most cases with the highest commonness-metric value at intermediate trait values. Across scales, belowground traits explained overall more variance in species commonness (19.4%) than aboveground traits (12.6%). The changes we found in the relationships between traits and commonness, when going from one spatial scale to another, could at least partly explain the maintenance of trait variation in nature. Most importantly, our study shows that within grasslands, belowground traits are at least as important as aboveground traits for species commonness. Therefore, belowground traits should be more frequently considered in studies on plant functional ecology.

Different sets of traits explain abundance and distribution patterns of European plants at different spatial scales

“…SLA is a productivity‐ and competitive ability‐related trait, that reflects species strategies for rapid acquisition of resources, with higher SLA values allowing a species to capture more light for a given biomass investment in leaves, for example (Díaz et al, 2004; Wright et al, 2004; Mariotte, 2014). In line with our findings, several studies state common species to be associated with higher SLA (Grime et al, 1997; Díaz et al, 2004; Mariotte, 2014; Lachaise et al, 2020). While species’ local abundances were best predicted by the interaction between leaf area and SLA, reflecting the leaf economics spectrum trait syndrome (Díaz et al, 2004), broad‐scale distribution metrics were best predicted by different combinations of traits.…”

“… 1 Mariotte (2014); 2 Lavergne et al (2004); 3 Lachaise et al (2020); 4 Bruelheide et al (2018); 5 Hedge & Ellstrand (1999); 6 Grime et al (1997); 7 Eriksson & Jakobsson (1998); 8 Kolb et al (2006); 9 Van der Veken et al (2007); 10 Thompson et al (1999); 11 Guo et al (2000); 12 Oakwood et al (1993); 13 Kelly & Woodward (1996); 14 Leishman & Murray (2001); 15 Güsewell (2004). …”

“…Similarly, on the local scale, common (i.e. more abundant) species have been associated with taller stature and with other traits that are proxies for species’ physiological activity and productivity, including larger specific leaf area (SLA) and higher leaf nitrogen (N) content (Grime et al, 1997; Hegde & Ellstrand, 1999; Lavergne et al, 2004; Mariotte, 2014; Lachaise et al, 2020). Nitrogen (N) and phosphorus (P) availabilities limit plant growth in most terrestrial ecosystems (Güsewell, 2004).…”

Allelopathic and competitive interactions between native and alien plants

“…Indeed, empirical studies found evidence that many invasive plants exert stronger competitive effects or are more tolerant to competition than many native ones (Kuebbing and Nuñez 2016;Golivets and Wallin 2018;Zhang and van Kleunen 2019). The high competitiveness of invasive aliens could be due to them having traits, such as high specific leaf area and low root tissue density (Pyšek and Richardson 2007;van Kleunen et al 2010;Lachaise et al 2021), which allow them to rapidly take up available resources, and consequently have high intrinsic growth rates (Dawson et al 2011;Zhang and van Kleunen 2019). However, as already pointed out by Baker (1974), the high competitiveness could also be due to the production of allelochemicals that suppress germination and growth of neighboring plants.…”

Allelopathic and Competitive Interactions Between Native and Alien Plants

“…Indeed, empirical studies found evidence that many invasive plants exert stronger competitive effects or are more tolerant to competition than many native ones (Kuebbing and Nuñez, 2016;Golivets and Wallin, 2018;Zhang and van Kleunen, 2019). The high competitiveness of invasive aliens could be due to them having traits, such as high speci c leaf area and low root tissue density (Pyšek and Richardson 2007;van Kleunen et al 2010;Lachaise et al 2020), which allow them to rapidly take up available resources, and consequently have high intrinsic growth rates (Dawson et al 2011;Zhang and van Kleunen 2019). However, as already pointed out by Baker (1974), the competitiveness could also be due to the production of allelochemicals that suppress germination and growth of neighboring plants.…”