Effects of litter quality and latitude on decomposition.

Decomposition of organic material (litter) is an important part of the global carbon cycle. Environmental conditions, litter quality and the microbial community are the main factors affecting decomposition. The decomposition is divided into two phases, one fast initial phase and one slow second phase. The tea bag index (TBI) was used as a standardized method to measure decomposition rate along a latitudinal gradient. A common garden set up and extractions were made to determine the composition of the litter to investigate if climate or litter quality affected the decomposition rate. The result showed that the decomposition rate increased with higher latitude. The litter from higher latitude has more material that is easy to decompose. Natural litter abroad had higher decomposition rate than at home. On the contrary, standard litter at home had higher decomposition rate than abroad. This indicates that litter quality is more important than latitude. Further studies are needed with more sites along the gradient to conclude how climate and litter quality are affecting decomposition.