Biological nitrogen fixation across major biomes in Latin America: Patterns and global change effects

Science of the Total Environment
By: , and 

Links

Abstract

Biological nitrogen fixation (BNF) supports terrestrial primary productivity and plays key roles in mediating human-induced changes in global nitrogen (N) and carbon cycling. However, there are still critical uncertainties in our understanding of the amount of BNF occurring across terrestrial ecosystems, and of how terrestrial BNF will respond to global change. We synthesized BNF data from Latin America, a region reported to sustain some of the highest BNF rates on Earth, but that is underrepresented in previous data syntheses. We used meta-analysis and modeling approaches to estimate BNF rates across Latin America's major biomes and to evaluate the potential effects of increased N deposition and land-use change on these rates. Unmanaged tropical and subtropical moist forests sustained observed and predicted total BNF rates of 10 ± 1 and 14 ± 1 kg N ha−1 y−1, respectively, supporting the hypothesis that these forests sustain lower BNF rates than previously thought. Free-living BNF accounted for two-thirds of the total BNF in these forests. Despite an average 30% reduction of free-living BNF in response to experimental N-addition, our results suggest free-living BNF rate responses to current and projected N deposition across tropical and subtropical moist forests are small. In contrast, the conversion of unmanaged ecosystems to crop and pasture lands increased BNF rates across all terrestrial biomes, mostly in savannas, grasslands, and dry forests, increasing BNF rates 2-fold. The information obtained here provides a more comprehensive understanding of BNF patterns for Latin America.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Biological nitrogen fixation across major biomes in Latin America: Patterns and global change effects
Series title Science of the Total Environment
DOI 10.1016/j.scitotenv.2020.140998
Volume 746
Year Published 2020
Language English
Publisher Elsevier
Contributing office(s) Southwest Biological Science Center
Description 140998, 15 p.
Other Geospatial Latin America
Google Analytics Metrics Metrics page
Additional publication details