Plant and soil δ13C and δ15N are linked to community biomass, litter production, and litter turnover rate in mature subtropical forests

Abstract

The natural abundance of 13 C and 15 N can integrate information on the dynamics of C and N, respectively. This study tested whether and how d 13 C and d 15 N of the plant and soil samples (including leaf, forest floor litters, fine roots, and 0-15 cm mineral soil) can detect local variations in community biomass, litter production, and litter turnover rate were explored in eight mature subtropical forests in southern China. Community biomass, litter production, and litter turnover rate were significantly positively correlated with each other and revealed similar correlations with other plant and soil parameters. Leaf d 13 C was significantly negatively correlated with litter production, suggesting the stomatal regulation of leaf gas exchange. Similar correlations were also observed for d 13 C of the mineral soil and other plant materials. Leaf and forest floor litters d 15 N were positively correlated with community biomass, litter production, and litter turnover rate. Such correlations were significantly positively mediated by soil availability of P rather than N, as demonstrated by the multiple regression analysis. In contrast, fine roots d 15 N was not related significantly to community biomass, litter production, or litter turnover rate. Significant differences in d 13 C and d 15 N among forests were related to the species composition, topography conditions, and land use history. Our results suggest that d 13 C and d 15 N of most plant and soil samples can indicate local variations in community biomass, litter production, and litter turnover rate in mature subtropical forests. Better understanding of these linkages could significantly improve our knowledge of C and N dynamics in forest ecosystems.

Cellulose in Foliage and Changes during Seasonal Leaf Development of Broadleaf and Conifer Species

“…Among their many other uses, the stable isotope composition of foliage samples can provide crucial information about kinetic fractionation of water stable isotopes [6,7], light dependency of carbon isotopes and carbon discrimination [8,9], the response of foliage to elevated CO 2 [10], water use efficiency [11], leaf-level physiological processes across climatic gradients [12], litter production and litter turnover [13], the effects of canopy aging [14], and leaf development over a complete growing season [15,16]. Furthermore, foliage samples provide information essential to paleoclimate studies [17][18][19].…”