¹⁵N NATURAL ABUNDANCE IN WOODY PLANTS AND SOILS OF CENTRAL BRAZILIAN SAVANNAS (CERRADO)

Abstract

We measured the 15 N natural abundance values of 320 individuals belonging to 45 different plant species of the Brazilian cerrado. We also determined δ 15 N of soil nitrogen as a function of soil depth. Our purpose was to test the hypothesis that N‐limited cerrado would have a large range of plant δ 15 N values, similar to patterns seen in northern high‐latitude ecosystems. Foliar δ 15 N values did demonstrate the large range found in some other N‐limited ecosystems, varying from −5‰ to +7.9‰. Significant variability within individual species was also seen across cerrado community types. Several factors contributed to this variability, including the presence of N‐fixing legumes, associations with mycorrhizal fungi, δ 15 N variability of soil organic matter with depth, fire events, and the seasonality of N‐immobilization and mineralization processes in cerrado soils.