Journal Article

Global patterns of foliar nitrogen isotopes and their relationships with climate, mycorrhizal fungi, foliar nutrient concentrations, and nitrogen availability

Wright, Ian J., Pardo, Linda H., Stock, William D., Templer, Pamela H., Mack, Michelle C., Nardoto, Gabriela B., Schuur, Edward A. G., Peñuelas, Josep, Welker, Jeffrey M., Bustamante, Mercedes, Dawson, Todd E., Hobbie, Erik A., Elmore, Andrew J., Virginia, Ross A., McLauchlan, Kendra K., Michelsen, Anders, Reich, Peter B., Aidar, Marcos P. M., Kahmen, Ansgar, Craine, Joseph M.

2009

Overview

Ratios of nitrogen (N) isotopes in leaves could elucidate underlying patterns of N cycling across ecological gradients. To better understand global-scale patterns of N cycling, we compiled data on foliar N isotope ratios (δ¹⁵N), foliar N concentrations, mycorrhizal type and climate for over 11 000 plants worldwide. Arbuscular mycorrhizal, ectomycorrhizal, and ericoid mycorrhizal plants were depleted in foliar δ¹⁵N by 2[per thousand], 3.2[per thousand], 5.9[per thousand], respectively, relative to nonmycorrhizal plants. Foliar δ¹⁵N increased with decreasing mean annual precipitation and with increasing mean annual temperature (MAT) across sites with MAT greater-than-or-equal -0.5°C, but was invariant with MAT across sites with MAT < -0.5°C. In independent landscape-level to regional-level studies, foliar δ¹⁵N increased with increasing N availability; at the global scale, foliar δ¹⁵N increased with increasing foliar N concentrations and decreasing foliar phosphorus (P) concentrations. Together, these results suggest that warm, dry ecosystems have the highest N availability, while plants with high N concentrations, on average, occupy sites with higher N availability than plants with low N concentrations. Global-scale comparisons of other components of the N cycle are still required for better mechanistic understanding of the determinants of variation in foliar δ¹⁵N and ultimately global patterns in N cycling.

• Publisher: Oxford, UK : Blackwell Publishing Ltd,Blackwell Publishing,Blackwell Publishing Ltd
• Subject: analysis / atmospheric precipitation / chemistry / Climate / climatic zones / Ecosystem / Ecosystems / ectomycorrhizae / Forest ecology / Forest soils / Fungi / isotopes / leaves / metabolism / Mycorrhizae / Mycorrhizal fungi / Nitrogen / Nitrogen - metabolism / nitrogen availability / nitrogen content / Nitrogen Isotopes / Nitrogen Isotopes - analysis / Nitrogen Isotopes - metabolism / phosphorus / Phosphorus - analysis / Plant Leaves / Plant Leaves - chemistry / Plant Physiological Phenomena / Plants / Rain / Research Review / Signatures / Soil ecology / Soil plant interactions / stable isotopes / Temperature / Terrestrial ecosystems / vesicular arbuscular mycorrhizae