Litter decomposition rates across tropical montane and lowland forests are controlled foremost by climate

OSTERTAG, REBECCA; RESTREPO, CARLA; DALLING, JAMES W.; MARTIN, PATRICK H.; ABIEM, IVEREN; AIBA, SHINICHIRO; ALVAREZ DÁVILA, ESTEBAN; ARAGÓN, ROXANA; ATAROFF, MICHELLE; CHAPMAN, HAZEL; CUEVA AGILA, AUGUSTA Y.; FADRIQUE, BELEN; FERNÁNDEZ, ROMINA D.; GONZÁLEZ, GRIZELLE; GOTSCH, SYBIL G.; POMA LÓPEZ, LAURA NOHEMY; TOBÓN, CONRADO; WILLIAMS, CAMERON B.

BIOTROPICA

WILEY-BLACKWELL PUBLISHING, INC

Año: 2021

0006-3606

The hierarchy of factors hypothesis states that decomposition rates are controlledprimarily by climatic, followed by biological and soil variables. Tropical montane forests(TMF) are globally important ecosystems, yet there have been limited efforts toprovide a biome-scale characterization of litter decomposition. We designed a commonlitter decomposition experiment replicated in 23 tropical montane sites acrossthe Americas, Asia, and Africa and combined these results with a previous study of23 sites in tropical lowland forests (TLF). Specifically, we investigated (1) spatial heterogeneityin decomposition, (2) the relative importance of biological factors that affectleaf and wood decomposition in TMF, and (3) the role of climate in determiningleaf litter decomposition rates within and across the TMF and TLF biomes. Litterbagsof two mesh sizes containing Laurus nobilis leaves or birchwood popsicle sticks werespatially dispersed and incubated in TMF sites, for 3 and 7 months on the soil surfaceand at 10?15 cm depth. The within-site replication demonstrated spatial variability inmass loss. Within TMF, litter type was the predominant biological factor influencingdecomposition (leaves > wood), with mesh and burial effects playing a minor role.When comparing across TMF and TLF, climate was the predominant control over decomposition,but the Yasso07 global model (based on mean annual temperature and precipitation) only modestly predicted decomposition rate. Differences in controlling factors between biomes suggest that TMF, with their high rates of carbon storage, must be explicitly considered when developing theory and models to elucidate carbon cycling rates in the tropics.