부산대학교 도서관

Globally widespread woody encroachment into grass-dominated ecosystems has substantial consequences for carbon (C), nitrogen (N), and phosphorus (P) cycles. Despite its significance as an essential macronutrient, however, little is known regarding potential changes in the sulfur (S) cycle. We quantified S concentrations, stoichiometric relationships, and δ34S values in the plant-soil environment to investigate landscape-scale changes in the S cycle following grassland-to-woodland transitions in a subtropical savanna. Plant tissues of woody species had significantly higher S concentrations and δ34S values than those of herbaceous species, resulting in a landscape-scale correspondence between spatial patterns of S and δ34S in surface soils (0–5 cm) and vegetation distribution, with higher S and δ34S in soils beneath woody patches. These patterns were more subtle at soil depths > 5 cm. Woody plants had higher N:S ratios but comparable P:S ratios relative to herbaceous species, which contributed to contrasting spatial patterns between N:S and P:S ratios in surface soils. Sulfur in surface soils increased proportionally less relative to N, but proportionally more compared to P. Our findings indicate that grassland-to-woodland transitions amplify landscape-scale S dynamics, especially in surface soils, and create a S-enriched environment that enables woody plants to acquire sufficient S relative to demand to support their continued productivity and proliferation. [ABSTRACT FROM AUTHOR]