Table 4.

Main aspects of presence or absence of surface vegetation.

Surface vegetation present	No surface vegetation
Continuous carbon and energy supply provided to underlying microbial communities	Root penetration alters favorable anaerobic conditions
Protection against wind and rain erosion	No protection from erosion sources
Preferential flow (or by-passing) of untreated stream due to dense plant growth and wildlife burrowing	Reduces natural aesthetic and denies original ecosystem function
Compaction of substrate layers which reduces system performance	Loose layering of substrates which provides good conductivity and connectivity
Densely vegetated wetlands require maintenance to ensure proper functioning	No maintenance with regard to vegetation