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Differences in nitrogen cycling between tropical dry forests with contrasting precipitation revealed by stable isotopes of nitrogen in plants and soils
Author(s) -
RiveroVillar Anaitzi,
Templer Pamela H.,
ParraTabla Víctor,
Campo Julio
Publication year - 2018
Publication title -
biotropica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.813
H-Index - 96
eISSN - 1744-7429
pISSN - 0006-3606
DOI - 10.1111/btp.12612
Subject(s) - cycling , biogeochemical cycle , nitrogen cycle , environmental science , soil water , canopy , precipitation , tropical and subtropical dry broadleaf forests , abundance (ecology) , ecology , tropical savanna climate , agronomy , biology , ecosystem , nitrogen , forestry , geography , chemistry , organic chemistry , meteorology
Despite the known links between climate and biogeochemical cycling of N in tropical forests, fundamental knowledge of N cycling is still far from complete. Our objective was to ascertain differences in the N cycle of two tropical dry forests under contrasting precipitation regime (1240 or 642 mm of mean annual rainfall). To do so, we examined a short‐term metric of N cycling (N concentration) and a more integrated metric of N cycling (natural abundance 15 N) in plants and soils at both sites. At both the relatively wet and dry sites, N cycling associated with two non‐N 2 ‐fixing species was compared to N cycling associated with two potential N 2 ‐fixing species; all four tree species considered were dominant at both sites. The 15 N abundance in plants was highest in the site with low rainfall, showing that N losses from the system may be large. By contrast, short‐term N metrics did not vary with rainfall. Although there was a trend for leaf N concentration to be elevated in trees that have potential associations with N 2 ‐fixers, only 15 N in the forest floor was significantly greater under trees with high canopy N (N 2 ‐fixing species) than those with low canopy N (non‐N 2 ‐fixing species). Within each site, the influence of N 2 ‐fixing species on N cycling increased with a reduction in rainfall. Overall, our results demonstrate the role of climate as a driver of N cycling in the region, such that the projected decrease in precipitation in this region may lead to larger N losses in these forests. This study also shows how changes in tree species with and without N 2 ‐fixing associations may impact N cycling in tropical dryland forests in the future.