Plant community composition affects the species biogeochemical niche

Ifigenia Urbina,Anke Jentsch,Jordi Sardans,Jüergen Kreyling,Carl Beierkuhnlein,Josep Peñuelas,Oriol Grau

doi:10.1002/ecs2.1801

Abstract

AbstractNutrients are essential for plant development, and their availability and stoichiometric ratios can influence the composition of plant communities. We investigated the possibility of the reverse influence: whether the conditions of contrasting species coexistence determine foliar element concentrations and plant stoichiometry, that is, species biogeochemical niche (BN). The experiment was conducted at the Ecological‐Botanical Garden of the University of Bayreuth, Germany. We analyzed foliar element concentrations of two dwarf shrubs (Calluna vulgaris and Vaccinium myrtillus) and two grasses (Holcus lanatus and Arrhenatherum elatius) growing in different community compositions (monocultures and various mixed stands). Foliar nutrient concentrations and stoichiometry (taken as a proxy of species BN) were species specific; each species showed its own BN in all communities. Furthermore, V. myrtillus and H. lanatus species shifted their BN in response to changes in their community, accomplishing the “biogeochemical niche displacement” hypothesis. We conclude that plants can readjust their foliar element concentration if they grow in communities with contrasting plant composition, suggesting a differential use of element resources when the patterns of species coexistence change. These results also support the complementary niche hypothesis.

Highlights

In recent decades, plant nutrient stoichiometry, defined as the relative proportion of C and nutrients in plant tissues, has gained significant importance in ecological studies (Elser and Urabe 1999, Sterner and Elser 2002, Moe et al 2005, Cross et al 2005, Elser and Hamilton 2007, Sardans et al 2012a)
The Principal component analyses (PCAs) of the four monocultures showed the separation of the dwarf shrub and grass functional groups on the first axis (P < 0.0001), which explained 56.4% of the variability (Fig. 2a, b)
The study provides evidence that plant stoichiometry responds to changes in plant community composition

Summary

Introduction

Plant nutrient stoichiometry, defined as the relative proportion of C and nutrients in plant tissues (leaves, roots, shoots, and wood), has gained significant importance in ecological studies (Elser and Urabe 1999, Sterner and Elser 2002, Moe et al 2005, Cross et al 2005, Elser and Hamilton 2007, Sardans et al 2012a). This is understandable because the composition of plant communities depends on several ecological processes and functions such as productivity, resource use, nutrient cycling, biotic interactions (Grime 1974, Tilman et al 1996, Roem 2000), while plant stoichiometry is influenced by several factors such as soil fertility, source and quantity of water supply, phylogenetic affiliation, and climatic conditions (Sterner and Elser 2002). Soil-layer interactions and competition with microbial communities make it difficult to establish a direct link between soil resources and plant diversity (Hooper and Vitousek 1997), increasing even further the difficulties associated with studying the link between plant stoichiometry and community composition

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Discussion

Conclusion