Plant Litter Decomposition in Terrestrial Ecosystems Compared to Streams

The decomposition of dead organic matter is critical for carbon and nutrient cycles across ecosystems from the bottom of oceans to mountain tops. Despite similarities in the driving abiotic and biotic factors, and interconnected flows of organic matter between streams and their surrounding riparian zones, litter decomposition has often been studied separately in aquatic and terrestrial ecosystems, with some notable exceptions. This collaborative research across systems has identified some common patterns, which is necessary to move towards a broader litter decomposition theory and to develop a global decomposition model. Here we compare terrestrial litter decomposition with that occurring in aquatic systems, by providing an overview of the terrestrial literature and highlighting commonalities and differences with decomposition in streams. Specifically, we look at (i) the influence of climate, decomposer communities (microbes and invertebrates) and leaf litter quality (chemical and morphological), (ii) the consequences of changing diversity (in decomposer and litter communities), and (iii) the effects of global change (climate warming, nitrogen deposition and biotic invasions) on litter decomposition. Lastly, we identify recent approaches developed in terrestrial ecosystems that may help to increase our understanding of the abiotic and biotic drivers, diversity effects and global change effects on litter decomposition in aquatic ecosystems.