Specific leaf area predicts dryland litter decomposition via two mechanisms

1. Litter decomposition plays important roles in carbon and nutrient cycling. In dryland both microbial decomposition and abiotic degradation (by UV light or other forces) drive variation in decomposition rates, but whether and how litter traits and position determine the balance between these processes is poorly understood.
2. We investigated relationships between litter quality and their decomposition rates among diverse plant species in a desert ecosystem in vertically contrasting positions representing distinct decomposition environments driven by different relative contributions of abiotic and microbial degradation. Thereto, leaf litter samples from 17 desert species were sealed into litterbags and placed on the soil surface under strong solar exposure versus shade conditions, or buried in the soil at 10 cm depth, for a whole year. 3. Litter decomposition rates were 21 and 17 % higher in burial and light-exposed treatments, respectively, than those in shade. Leaf traits, i.e. sp...