Home-field advantage of woody debris decomposition and its response to the drought on the Loess Plateau, China.

Abstract

Studying the home-field advantage (HFA) in woody debris decomposition is crucial for accurately estimating carbon fluxes of woody debris and its contribution to forest carbon balance. We conducted a decomposition experiment with reciprocal transplantation using woody debris of two dominant afforestation species (Robinia pseu-doacacia and Pinus tabuliformis) on the Loess Plateau, China. We set up three different rainfall levels: control (0% precipitation reduction), 40% precipitation reduction, and 80% precipitation reduction. By monitoring the microbial respiration carbon fluxes of woody debris for one year, we investigated the HFA effect of woody debris decomposition and its drought response. The results showed that the HFA effect was negatively correlated with substrate quality. R. pseudoacacia debris exhibited non-significant HFA, while P. tabuliformis debris with lower substrate quality displayed significant positive HFA. Fungal community structure in R. pseudoacacia debris showed no difference between home and away fields, whereas P. tabuliformis debris had distinct fungal community between home and away fields (R²=0.22). Debris of both species demonstrated significantly higher abundance of potential key species in the fungi at the home fields, with P. tabuliformis debris microbial respiration showing positive correlation with Basidiomycetes abundance (R²=0.23). In the Loess Plateau region with low moisture content, HFA effects of woody debris decomposition were primarily regulated by tree species identity and were not sensitive to drought-induced moisture change.