Stoichiometric homeostasis: a test to predict tundra vascular plant species and community-level responses to climate change

Abstract

Climate change is having profound influences on Arctic tundra plant composition, community dynamics, and ecosystem processes. Stoichiometric homeostasis (H), the degree to which a plant maintains its internal nutrient concentrations independent of nutrient variations in its environment, may be a useful approach to predict the impacts of these influences. In this case study, we used fertilization manipulation data to calculate homeostasis indices based on nitrogen (H N ), phosphorus (H P ), and nitrogen to phosphorus ratios (H N:P ) of aboveground tissues for seven common tundra vascular species belonging to three growth forms. We then analyzed species H relationships with dominance, spatial stability, and responsiveness to various experimental manipulations. Each of the H indices was correlated amongst tissue types within each species and was generally highest in ericoid mycorrhizal host species and lowest in the ectomycorrhizal birch. Species H P and H N:P were consistently positively correlated with aboveground biomass within the controls and across all manipulations. Furthermore, these same species were spatially stable across experimentally warmed field plots. Stoichiometric homeostasis theory has been successful in predicting grassland community dynamics. This first test of its applicability across a variety of Arctic plant growth forms highlights its considerable potential in predicting tundra plant community structure and responses to environmental change.Key words: Arctic tundra, nitrogen, phosphorus, species dominance, spatial stability.Résumé : Le changement climatique a des effets considérables sur la composition des plantes de la toundra arctique, la dynamique de communauté et les processus d'écosystème. L'homéostasie stoechiométrique (H), le degré auquel une plante maintient ses concentrations de nutriments internes indépendamment des variations de nutriments dans son environnement, peut être une approche utile pour prédire les impacts de ces effets. Dans cette étude de cas, nous avons utilisé des données de manipulation de fertilisation afin de calculer les indices d'homéostasie en fonction de l'azote (H N ), du phosphore (H P ) et des rapports azote à phosphore (H N:P ) de tissus épigés, et ce, pour sept espèces vasculaires de toundra communes appartenant à trois formes de croissance. Nous avons alors analysé les relations d'H des espèces en rapport avec la dominance, la stabilité spatiale et la réactivité à diverses manipulations expérimentales. Chacun des indices d'H a été corrélé parmi les types de tissus propres à chaque espèce et était généralement le plus élevé chez les espèces hôtes éricoïdes mycorhiziennes et le plus bas chez le bouleau ectomycorhizien. L'H P et l'H N:P des espèces étaient systématiquement positivement corrélés avec la biomasse épigée entre les contrôles et pour toutes les manipulations. En outre, ces mêmes espèces étaient stables spatialement sur l'ensemble des parcelles de terrain réchauffées à titre expérimental. La théorie d'homéos-tasie stoechiométrique a eu...

Submerged Macrophytes Exhibit Different Phosphorus Stoichiometric Homeostasis

“… Yu et al (2010) demonstrated that the stoichiometric homeostasis of Inner Mongolia grassland plants was positively correlated with its dominance and productivity in ecosystems, and plant communities with a high level of homeostasis also had a highly stable structure and function. The study by Gu et al (2017) also showed that the phosphorus (P) and nitrogen (N): P stoichiometric homeostasis indices ( H P ’s) of tundra plants were positively correlated with the biomass of their aboveground parts.…”

Comparison of C:N:P Stoichiometry in the Plant–Litter–Soil System Between Poplar and Elm Plantations in the Horqin Sandy Land, China

“…The degree of stoichiometric homeostasis appears to vary among organs ( Bai et al, 2019 ), reflecting a fundamental trade-off in nutrient investment and allocation among organs ( Gu et al, 2017 ). In this study, elm branch and root N concentrations and root N:P showed strict homeostasis, whereas the leaf N concentrations and N:P were weakly plastic and weakly homeostatic, respectively ( Table 3 ).…”

Stoichiometric homeostasis of wetland vegetation along a nutrient gradient in a subtropical wetland. Understanding stoichiometric mechanisms of nutrient retention in wetland macrophytes

“…The concept of stoichiometric homeostasis was formulated as a means to understand patterns of C, N and P in zooplankton to evaluate food quality and nutrient recycling (Jotaro Urabe et al 1995; Elser and Urabe 1999; J. Urabe and Sterner 2001; Sterner and Elser 2002; Malzahn et al 2007; Mulder 2007; Mulder and Bowden 2007). Later, the concept has been broadened to understanding food web stoichiometric dynamic (Persson et al 2010), specific stream food web stoichiometric interactions (Feijoó et al 2014), resource dependence of bacteria (Makino et al 2003), and grassland community level responses to climate change (Gu et al 2017). The stoichiometric homeostasis conceptual model is thus of particular interest with respect to nutrient enrichment and biotic uptake processes due to selective uptake of nutrients during nutrient enriched conditions (Sterner and Elser 2002; Small et al 2009).…”

“…While limited to a few studies, prior work suggest that plants range in their degree of homeostasis from very weak to non-homeostatic (Yu et al 2011; Gu et al 2017). However, these studies focused on terrestrial grasses and shrub species and not wetland plant species distributed along a nutrient gradient.…”