Microbial Communities of Decomposing Litter in Forested Headwater Streams: A Tropical and Temperate Comparison

Document Type


Publication Date



Organic matter decomposition rates in streams can be influenced by initial resource quality, hydrology and colonizing communities. Differences in breakdown rates in tropical and temperate streams may be explained by resource quality and differences in colonizing microbial communities. We used Terminal Restriction Fragment Length Polymorphism (T-RFLP) to assess microbial communities on decomposing leaves in two forested headwater streams. Leaf packs were deployed at Luquillo LTER (Dacryodes excelsa and Cecropia schreberiana) in June 2012 and at Coweeta LTER (Acer rubrum and Quercus prinus) in June 2013. Decay rates and microbial community structure were analyzed for each site. Microbial diversity was analyzed by estimating richness, Shannon’s diversity, and evenness. We predicted that differences in microbial community diversity are correlated with leaf decay rates. Average bacterial richness was similar between temperate (25.37±0.77) and tropical (24.90±1.54). Likewise, average fungal richness was similar between temperate (13.00±0.65) and tropical (15.13±1.24). Preliminary nMDS results show that microbial community structure differs between regions and leaf type. This suggests that despite similarities in richness, each region may have a unique suite of microbes taking over the decay process.


Joint Aquatic Sciences Meeting (JASM)


Portland, OR