What control home‐field advantage of foliar litter decomposition along an elevational gradient in subtropical forests?

Aims

The Home-Field Advantage (HFA) suggests that litter decomposes faster in its "home" habitat (home-field) due to local decomposer communities being more adapted to decomposing "home" litter. Elevation-induced micro-environmental variations, may break down the relationship between litter and its associated decomposer communities, reducing decomposition efficiency in home-field environments. In study, we aim to explore whether litter decomposition shows HFA across elevational gradients, the driving factors of litter mass loss in home and away, and what controls the litter HFA along the elevational gradient in subtropical forests.

Methods

In this study, we conducted a foliar litter decomposition translocation experiment along different elevational gradients (900 m-1600 m) in Daiyun Mountain in southeast China, using a 400 m elevational gradient (with a temperature variation of approximately 1.8 ℃) as the span for litter decomposition. We collected data on environmental factors (e.g., air and soil temperature, soil total C, N, P, and water content), foliar litter quality (e.g., total carbon, nitrogen and phosphorus contents), decomposer communities (soil fungal and bacterial biomass) and plant leaf traits (e.g., leaf total C, N, P, specific leaf area, and leaf dry matter content) at different elevations. Then mixed linear models and structural equation models were used to investigate differences in foliar litter decomposition between home and away fields, as well as the driving factors for HFA.

Results

We found that (1) Litter decomposition showed HFA across elevational gradients, with foliar litter in home-field losing more mass than in away-field along these gradients. (2) Environmental factors were the main driving factors influencing home-field litter decomposition, while litter quality was the main factor affecting away-field litter decomposition and HFA. Fungal communities enhanced home litter decomposition but not away-field litter, supporting decomposer control in home-field decomposition. (3) From the structural equation model, environmental factors and litter quality were significant positive drivers of HFA. In addition, litter quality was the main factor influencing home-field decomposition, as the faster decomposition of home-field foliar litter was a direct positive contributor to HFA, while slower decomposition of away-field litter had a direct negative effect.

Conclusions

Foliar litter decomposition along the elevational gradients exhibited HFA in Daiyun Mountain of subtropical regions, environmental factors are the main factors affecting home litter mass loss, while litter quality is the main factor affecting away litter mass loss and HFA. Additionally, environmental factors influenced microbial communities, with fungal communities having a significant positive effect on the home litter mass loss but no significant impact on away, supporting the decomposer control hypothesis. Therefore, global climate change may affect litter decomposition by altering environmental conditions, which is crucial for nutrient cycling in ecosystems, particularly in mountainous regions where elevational differences create diverse micro-environments. Understanding the Home-Field Advantage at different elevations could help predict forest responses to global change, especially in areas sensitive to elevational shifts in climate.