Global patterns of litter decomposition in drylands

SIEBENHART, IA; SARQUIS, A; TOGNETTI, PM; BIANCARI, L; AUSTIN, AT

Ciudad Autónoma de Buenos Aires

Simposio; FRONTIERS IN BIOSCIENCE 4; 2023

Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)

Predicting the global balance of carbon (C) in terrestrial ecosystems is essential to facing the current scenario of global change. Specifically, our understanding of the factors that control C recycling on a global scale in drylands is limited. In this work, we evaluate litter decomposition patterns on a global scale using the "aridec" database with information from 116 drylands on five continents. We evaluated the relationship between decomposition rates (k) and 7 climatic variables using mixed linear models. The selected model included the mean annual temperature, the synchrony between monthly temperature and precipitation, precipitation variability, and the percentage of cloudy days, and explained 18% of the variability in decomposition rates (R2m=0.18). In coincidence with local decomposition patterns, we showed that mean annual precipitation doesn’t predict decomposition for drylands at the global scale. Our results showed a contrasting pattern for decomposition rates in drylands in comparison with the PPNA pattern. Specifically, our macroclimate model predicted higher decomposition rates for more arid ecosystems characterized by a warmer and monsoonier climate. This study represents a starting point for disentangling the most important predictors of decomposition in drylands at different scales. In a context of global change where drylands are expanding and changing, understanding which are the dominant controls on litter decomposition will be essential for predicting the contribution of drylands to the global C balance.