Foliar and soil δ15N values reveal increased nitrogen partitioning among species in diverse grassland communities

摘要: Plant and soil nitrogen isotope ratios (δ¹⁵N) were studied in experimental grassland plots of varying species richness. We hypothesized that partitioning different sources among four plant functional groups (legumes, grasses, small herbs, tall herbs) should increase with diversity. Four years after sowing, all soils depleted ¹⁵N the top 5 cm whereas non-legume enriched at 5-25 depth. Decreasing foliar δ¹⁵N Δδ¹⁵N (= δ¹⁵N-soil δ¹⁵N) values legumes indicated increasing symbiotic N₂ fixation In also decreased diversity suggesting enhanced uptake N ¹⁵N. Foliar herbs unaffected by grasses reduced containing legumes, indicating direct use legume-derived Increased concentrations without these obtained additional mineral was not consumed legumes. These group specific shifts indicate complementary resource diverse communities.