Biogeographical Differentiation and Key Drivers of the Home-Field Advantage in Cross-Habitat Litter Decomposition: A Global Meta-Analysis

Global climate change and human activities have jointly exacerbated habitat fragmentation and expanded ecotones, significantly increasing the frequency and intensity of cross-habitat litter decomposition. The phenomenon whereby litter decomposes faster in its habitat of origin (“home”) than in other habitats (“away”) is known as the home-field advantage (HFA) effect. In-depth exploration of its core mechanisms and key drivers is crucial for revealing the spatial heterogeneity of global carbon and nitrogen cycles and for refining the theory of substance cycling in forest ecosystems. This study integrated 1410 observations from 102 published studies and used meta-analysis to systematically evaluate global patterns, biogeographical differentiation, and key drivers of the HFA effect. The results show that the HFA exhibits significant biogeographical differentiation and is driven by multiple factors. Globally, we found a significant positive HFA (LnRR = 0.0576, p < 0.05), with decomposition-related metrics (e.g., mass loss, decomposition rate) being 5.9% higher at home than away. The strength of the HFA effect shows significant dependence on climate and vegetation types. Regarding vegetation type, significant home-field advantages were observed for coniferous forests (10.15%), deciduous broadleaved forests (8.31%), and evergreen broadleaved forests (6.57%), while no significant differences were detected for shrublands or grasslands. Regarding climate type, subtropical (6.46%), temperate (9.20%), and cold/highland climates (9.53%) exhibited significantly higher home-site effects, whereas tropical and arid/semi-arid climates showed no significant differences. All analyses demonstrated substantial heterogeneity (I2 = 65.5–98.3%). This study also systematically analyzed the associations of three core factor categories (environmental factors such as elevation and precipitation, litter chemical composition, and soil chemical properties) with HFA effect. Among these factors, Litter C/P and Litter N/P were verified as significant positive regulatory factors governing the HFA effect. In conclusion, the driving mechanism of the HFA exhibits systemic characteristics that manifest as the interactive and synergistic effects of multiple factors rather than the independent control of a single factor. Specifically, climate and vegetation types jointly dominate the formation of its macro-geographical patterns, while local abiotic factors (e.g., altitude, precipitation) and litter properties (e.g., chemical composition) further and precisely regulate the strength of the HFA effect through complex interactions. Based on a systematic evaluation using meta-analysis, this study provides an important theoretical basis and data support for understanding the driving mechanisms of the HFA effect in cross-habitat litter decomposition across different ecosystems.