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Biomass partitioning in response to intraspecific competition depends on nutrients and species characteristics: A study of 43 plant species
Author(s) -
Rehling Finn,
Sandner Tobias M.,
Matthies Diethart
Publication year - 2021
Publication title -
journal of ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.452
H-Index - 181
eISSN - 1365-2745
pISSN - 0022-0477
DOI - 10.1111/1365-2745.13635
Subject(s) - nutrient , intraspecific competition , biology , biomass (ecology) , interspecific competition , perennial plant , competition (biology) , niche differentiation , herbaceous plant , agronomy , nutrient density , dominance (genetics) , forb , old field , plant community , plant ecology , botany , ecology , niche , grassland , ecological succession , gene , biochemistry
Competition simultaneously limits the availability of above‐ and below‐ground resources for plants. How plants respond to density with changes in patterns of biomass allocation is poorly understood. Previous studies had inconsistent results, but emphasised increased biomass allocation to stems in response to density. However, the response of plants to density may depend on environmental conditions and on characteristics of the species. We grew 43 herbaceous plant species at three densities (1, 8 and 64 individuals per pot) and two nutrient levels in a common garden and measured biomass allocation to roots (RMF), leaves (LMF) and stems (SMF), and specific root (SRL) and stem length (SSL). The species differed in functional group (grasses, forbs and legumes), life span and realised niche with respect to nutrients (Ellenberg's nutrient indicator value). Intraspecific competition and self‐thinning increased with nutrient supply. Overall, plants increased their RMF with density independent of nutrient level, indicating that competition was mainly for below‐ground resources. However, characteristics of the species influenced their responses to density and nutrients in terms of biomass allocation, SRL and SSL. At high densities, legumes were more productive than the other functional groups and hardly changed their allocation patterns, suggesting that they were less nutrient limited due to their mutualism with nitrogen‐fixing rhizobia. The SRL of perennials was lower, and their RMF was higher and increased more strongly in response to density than that of annuals, which could be interpreted as mechanisms to increase survival. The realised niche of species with respect to nutrients influenced the response to density and nutrients in terms of SMF, LMF, SRL and SSL in line with adaptations to both nutrient availability and competition for light in the typical habitats. Synthesis . We found that intraspecific competition was mainly for below‐ground resources, which may be typical for many species growing in moderately nutrient‐rich but high‐light habitats. Our results show that growth conditions, species characteristics and their interactions influence patterns of biomass allocation and plant morphology.