Environmental factors and traits that drive plant litter decomposition do not determine home-field advantage effects

1. The ‘home-?eld advantage’ (HFA) hypothesis predicts that plant litter is decomposed faster than expected underneath the plant from which it originates (‘home’) than underneath oth er plants (‘away’), because decomposer communities are specialized to break down litter from the plants they associate with. However, empirical evidence shows that the occurrence of HFA is highly variable, and the reasons for this are little understood. 2. In our study, we progress our underst anding by investigating whether HFA is stronger for more recalcitrant litter types and under colder conditions and how soil propert ies and plant functional traits a?ect the magnitude and direction of HFA. 3. In subarctic tundra in northern Sweden, we set up a reciprocal transplant litter decomposition exp erimen t along an elevational gradient where three highly contrasting vegetation types (heath, meadow and Salix) occur at all elevations, and where temperature decreases strongly with eleva- tion. In this study, we used a litter bag approach where litters from each elevation 9 vegetation type combination were decomposed in all combinations of elevation 9 vegetation type. We also mea sured community-level plant fu nctional traits, such as leaf and litter nutrient content. We dete rmined soil biotic and abiotic properties, such as microbial biomass and soil nutrient con- tent, in soil cores collected for each elevation 9 vegetation type combination. 4. We found that mass loss increased with plant and litter nutrient content and with soil tem- perature. In contrast, the occurrence of HFA was limited in our study system, and its magni- tude and direction could not be explained by vegeta tion type, elevation, plant traits or soil properties, despite these factors serving as powerful drivers of litter mass loss in our study. 5. We conclude that although vegetation type and climate are major drivers of litter mass loss, they do not emerge as important determinants of HFA. Therefore, while rapid shifts in plant community composition or temperature due to global ch ange are likely to in?uence litter mass loss directly by altering environmental conditions, plant trait spectra and litter quality, indirect e?ects of global change resulting from decoupling of specialist inter actions between litter and decomposer communities appear to be of less importance.