Interspecific vs intraspecific patterns in leaf nitrogen of forest trees across nitrogen availability gradients

Abstract

SummaryLeaf nitrogen content (d) coordinates with total canopy N and leaf area index (LAI) to maximize whole-crown carbon (C) gain, but the constraints and contributions of within-species plasticity to this phenomenon are poorly understood.Here, we introduce a game theoretic, physiologically based community model of heightstructured competition between late-successional tree species. Species are constrained by an increasing, but saturating, relationship between photosynthesis and leaf N per unit leaf area. Higher saturating rates carry higher fixed costs.For a given whole-crown N content, a C gain-maximizing compromise exists between d and LAI. With greater whole-crown N, both d and LAI increase within species. However, a shift in community composition caused by reduced understory light at high soil N availability (which competitively favors species with low leaf costs and consequent low optimal d) counteracts the within-species response, such that community-level d changes little with soil N availability. These model predictions provide a new explanation for the changes in leaf N per mass observed in data from three dominant broadleaf species in temperate deciduous forests of New England.Attempts to understand large-scale patterns in vegetation often omit competitive interactions and intraspecific plasticity, but here both are essential to an understanding of ecosystem-level patterns.

The world‐wide ‘fast–slow’ plant economics spectrum: a traits manifesto

“…Moreover, the average canopy [N] is influenced by trait‐based competitive interactions that influence the abundance‐weighted [N] (H2–4) (Dybzinski et al . ). Thus, traits of species and biotic interactions between species together regulate the scaling up of resource economics from leaf to ecosystem.…”

Continuous planting under a high density enhances the competition for nutrients among young Cunninghamia lanceolata saplings

“…Plant density greatly affects plantation productivity. A high planting density can reduce biomass production, decrease the photosynthetic efficiency, and change the resource use efficiency (Mediavilla et al 2001;Wang et al 2005;Dybzinski et al 2013;Chen et al 2014). Although these differences are species specific and vary with the developmental stage, a decrease in the photosynthetic rate frequently occurs in many plants, especially in saplings.…”

How virtual shade sheds light on plant plasticity

“…The model system presented here complies with these three requires. In that manner it builds on previous game theoretical studies (Dybzinski et al, 2013;Farrior et al, 2013;Vermeulen, 2014) that considered plasticity but focussed on absolute trait values expressed in different environments rather than dynamic trait responses as was done here. We thus argue that our approach provides a useful complementary approach to analyse natural selection for plasticity (Bongers et al, 2014).…”

“…EGT models have been used extensively to determine ESS-traits regarding light competition (Iwasa et al, 1984;Anten, 2002Anten, , 2005Pronk et al, 2007;Dybzinski et al, 2011Dybzinski et al, , 2013Farrior et al, 2013;van Loon et al, 2014). Some of these models considered trait plasticity (Dybzinski et al, 2011(Dybzinski et al, , 2013Farrior et al, 2013). However, these models focussed mainly on the expressed traits, not on selection for the plastic response itself.…”

“…Currently evolutionary and ecological dynamic population models are widely used to explain genetic variation and species composition in different environments, and these models are often based on evolutionary game theoretical (EGT) principles (Falster & Westoby, 2003;Anten & During, 2011;McNickle & Dybzinski, 2013;Dybzinski et al, 2015). However, these models do usually not consider phenotypic plasticity and therefore will predict selection for different genotypes in different environments when these environments select for different traits (but see Dybzinski et al, 2013). However, if plasticity would be considered, selection for different traits would not necessarily lead to selection for different genotypes, because a single plastic genotype can express multiple phenotypes.…”