Loss of biodiversity and species richness:
Phragmites causes a decrease in biodiversity by developing into monoculture stands which crowd out native vegetation and wildlife.
Loss of habitat:
Monoculture stands result in a decrease in available natural habitat and food supply for various wildlife species, which may include Species at Risk. Phragmites stalks are rigid and tough, and do not allow for wildlife or humans to easily navigate through a stand.
Changes in hydrology:
Phragmites produces a substantial amount of dead stocks which accumulate with time. This slowly decomposing material can interrupt surface and shallow groundwater flows in coastal areas, favouring its growth.
Changes in nutrient cycling:
Phragmites stalks are made of a very inflexible structural material which breaks down very slowly, leaving a high proportion of recalcitrant biomass (carbon) in the standing dead stalks.
Increased fire hazards:
The high percentage of dead stalks within a stand are dry and combustible, increasing the risk of fires.
Economic and social impacts:
Phragmites can have many negative effects on economic and social issues. Effects on agriculture and crops can lead to economic losses, while monoculture stands can affect property values, recreation and raise aesthetic concerns.