Roots and associated mycorrhizal fungi are important determinants of leaf litter decomposition and home-field advantage in subtropical forests

Abstract Aims The ‘home-field advantage (HFA) hypothesis’ predicts that litter decomposes faster in its original environment (“home”) than in the foreign environment (“guest”). The vast majority of tree species are primarily symbiotic with arbuscular mycorrhizal (AM) or ectomycorrhizal (ECM) fungi. To date, how different roots and associated mycorrhizae affect litter decay rates and HFA effects is not well known. Methods To fill this gap, we conducted a litter transplant and mycorrhizal-cut experiment in one arbuscular mycorrhizal (AM)- and one ectomycorrhizal (ECM)- associated tree species plantation in subtropical China, and tested whether roots and their associated mycorrhizal fungi affect the litter decomposition rate and HFA effect. Results Over a period of 720 days, we found that AM litter rots faster in the presence of fine roots and mycorrhizae at home, while the ECM litter decomposition rate did not change significantly with and without roots and mycorrhizae. AM litter showed no HFA effect regardless of the presence or absence of roots and associated mycorrhizae, while ECM litter showed a negative HFA effect only in the presence of roots and mycorrhizae. The negative HFA effect of ECM litter was attributed to the higher saprophytic fungal abundance and P-acquiring enzyme activities in the guest than in the home environment. Conclusions Our results indicated that variation in the interaction between mycorrhizal and saprotrophic fungi is a key factor in determining litter decomposition rates and the HFA effect through modification of saprophytic fungal abundance and P-acquiring enzyme activities.