Enzymatic efficiency of the decomposing microbiota: what does really matter for aquatic macrophytes invasions?
Biological invasions have negative impacts on different ecosystem-level functions, such as nutrient cycling. In aquatic environments, exotic litter can change the activity of the decomposer microbiota. We tested whether litter quality, litter decay, and enzyme activity differed between native Egeria densa and exotic Hydrilla verticillata. The invasive plant presented higher lignin and lower cellulose content than the native plant. Both species showed rapid fibre decay in the first five days. E. densa had higher cellulose and hemicellulose decay than H. verticillatta. Although the species did not exhibit differences in enzyme activity over time, E. densa had a higher enzymatic efficiency than H. verticillata. This differential enzymatic performance can cause changes in the mineralisation processes of the invaded environments. The lower decomposition rates for invasive litter, associated with differences in litter quality, could increase the amount of particulate organic material in invaded environments.