Latitudinal gradients and scaling regions in trait space: Taylor’s power law in Japanese woody plants

Abstract

Aim Taylor's power law (TPL) is a variation of the variance:mean ratio and is often used to describe over‐ or underdispersed ecological distributions. We hypothesize that TPL is also applicable to the distribution of species traits and that the respective power law parameters might determine ecological functioning. Here, we aim to study this hypothesis in detail. Location East Asian islands, including the Japanese and Ryukyu archipelagos. Time period 1968–2015. Major taxa studied Gymnosperm and angiosperm woody plant species. Methods We used the geographical distribution of 946 Japanese woody plant species at the 10 km × 10 km grid cell level. Based on leaf and wood samples and literature data, we studied 10 important plant traits (maximum plant height, average fruit and seed size, specific leaf area, leaf thickness, wood density, leaf tannin and phenol content, and C/P and C/N ratios) and related trait variability to minimum absolute temperature, land and forest area and to the variability in forest cover and elevation using bi‐ and multivariate and piecewise regression analysis. Results The variability in the trait expression was well described by TPL. Average trait expression and the respective variability changed predictably along the latitudinal gradient, resulting in a general tendency towards trait clustering (TPL slopes > 1.0). Piecewise regression detected significant breakpoints in the TPL pattern for most traits. Minimum ambient temperature and latitude were the most important predictors of the variability in the observed TPL slopes. Main conclusions Taylor's power law appears to be trait specific and cannot be used as a diagnostic ecological character. We propose a new linear model to quantify ecological variability that includes average variable expressions and ecological covariates. We argue that common measures to quantify ecological variability based on the variance:mean ratio might give false impressions about the true degree of variability because they do not account for the variance–mean allometry.

Land use and climate change affects butterfly diversity across northern Austria

“…Because the variance r 2 of ecological variables generally increases with average variable expression l according to Taylor's power law (r 2 = cl z ; Taylor 2019), we followed the approach of Ulrich et al (2021) and combine Eq. 1 with Taylor's power law and additional environmental variables into the additive model…”

Intraspecific Trait Variability Determines Understorey Plant Community Assembly

“…We call for respective individual based studies of local plant trait and species cooccurrences (cf. Ulrich et al 2021).…”

“…In June and July 2020 understorey plant samples were undertaken in 25 4 × 4 m2 plots each at two seminatural mixed temporal forest sites near Toruń (53.2°N, 18.5°E) in Northern Poland (cf. Ulrich et al 2021 for detailed descriptions of the study sites). Plots within each site were selected for homogeneous soil and microclimate conditions.…”

“…Here, we try to ll these knowledge gaps and link the intraspeci c variability of important functional traits in Polish mixed temperate forest understorey plants to small scale community assembly and functional diversity. We focus on the small balsam Impatiens parvi ora, a dominant species in these forests (Ulrich et al 2021). As I. parvifora is not only dominant but also one of the largest herbaceous species it locally accounts for more than half of the total understorey plant biomass (Ulrich et al 2021).…”

“…We focus on the small balsam Impatiens parvi ora, a dominant species in these forests (Ulrich et al 2021). As I. parvifora is not only dominant but also one of the largest herbaceous species it locally accounts for more than half of the total understorey plant biomass (Ulrich et al 2021). Therefore, we expected to see detectable effects of trait expression and trait variability of this species on the abundances, community composition, and species richness of other plants.…”