J Plant Ecol ›› 2020, Vol. 13 ›› Issue (3): 378-386.DOI: 10.1093/jpe/rtaa021

• Research Articles • Previous Articles    

Inter- and intraspecific variability of plant individual growth and its role on species ranking in grasslands

Rémi Perronne1, *, Franck Jabot2 and Julien Pottier1   

  1. 1 UCA, INRAE, VetAgro Sup, UMR Ecosystème Prairial, site de Crouel, 5 chemin de Beaulieu, F-63000 Clermont-Ferrand, France, 2 UCA, INRAE, UR LISC, Centre de Clermont-Ferrand, 9 avenue Blaise Pascal, F-63178 Aubière, France

    *Corresponding author. E-mail: remi.perronne@inrae.fr
  • Received:2019-12-16 Revised:2020-03-03 Accepted:2020-05-21 Online:2020-05-27 Published:2020-06-01

Abstract:

Aims

Individual growth constitutes a major component of individual fitness. However, measuring growth rates of herbaceous plants non-destructively at the individual level is notoriously difficult. This study, based on an accurate non-destructive method of aboveground biomass estimation, aims to assess individual relative growth rates (RGRs) of some species, identify its environmental drivers and test its consequences on community patterning. We specifically address three questions: (i) to what extent environmental conditions explain differences in individual plant growth between sites, (ii) what is the magnitude of intraspecific variability of plant individual growth within and between sites and (iii) do species-averaged (dis-)advantage of individual growth compared with the whole vegetation within a site correlate with species ranking at the community level?

Methods

We monitored the growth of individuals of four common perennial species in 18 permanent grasslands chosen along a large pedoclimatic gradient located in the Massif Central, France. We measured soil properties, levels of resources and meteorological parameters to characterize environmental conditions at the site level. This design enables us to assess the influence of environmental conditions on individual growth and the relative extent of inter-individual variability of growth explained within and between sites. We determined the ranking of each of the four species in each site with botanical surveys to assess the relationship between species-averaged growth (dis-)advantage relative to the whole community and species rank in the community.

Important Findings

We found that environmental conditions explain a significant proportion of individual growth variability, and that this proportion is strongly variable between species. Light availability was the main driver of plant growth, followed by rainfall amount and potential evapotranspiration, while soil properties had only a slight effect. We further highlighted a moderate to high within-site inter-individual variability of growth. We finally showed that there was no correlation between species ranking and species-averaged individual growth.

Key words: relative growth rate, species ranking, non-destructive biomass estimation, temperate permanent grasslands, inter-individual variability

摘要:

植物个体的生长是其适合度的重要组成部分。然而,在个体水平上非破坏性地测量草本植物的生长速度非常困难。本研究基于准确的非破坏性地面生物量估算方法,旨在评估某些物种的个体相对生长速率,识别其环境驱动因子,并检验其对群落模式的影响。我们提出以下三个具体的科学问题:(1)环境条件可以在多大程度上解释个体植物生长在不同样地间的差异;(2)在相同样地内和不同样地间,植物个体生长的种内差异有多大,以及(3)相同样地内,平均每个物种的个体生长相较于整个植被的优势/劣势,与群落水平的物种等级是否有关?为了回答上述问题,我们在法国中央高地沿古气候梯度的18 个永久草地内监测了4种常见的多年生植物的个体生长。我们测量了土壤性质、资源水平和气象参数,以表征样地的环境条件。这使我们能够评估环境条件对个体生长的影响,以及在相同和不同样地之间个体间生长变异的相对程度。我们通过植物学调查确定了每个样地内四个物种的等级,以评估物种平均个体生长相对于整个群落的优势劣势与物种在群落中的等级之间的关系。研究结果表明,环境条件解释了个体生长变异性很重要的一部分,而且这部分变异在物种之间也有很大差异。光照有效性是影响植物生长的主要因素,其次是降雨量和潜在的蒸散量,而土壤性质对植物生长的影响较小。我们的结果进一步强调了相同样地内个体间生长变异的程度是中到高,而且物种等级与物种平均个体生长之间没有相关性。

关键词: 相对生长率, 物种等级, 非破坏性生物量估算, 温带永久草地, 个体间变异