One of the primary reasons for bracken control is to avoid the development of a dominant monoculture and the reduction of diversity of species in an area.
Bracken has the ability to smother more sensitive habitats, such as heather moorland, and evidence of this can be seen in many parts of the UK. The smothering process is achieved by the fronds blocking light and rainfall and through the bracken litter that prevents other species establishing.
Bracken litter provides an ideal moist, warm habitat for sheep ticks and the spread of bracken has been linked to a perceived increase in tick numbers. Sheep ticks spread diseases that, in addition to affecting birds, wild and domestic livestock, can also be transmitted to people (e.g. Lyme disease) and pets. The carcinogenic properties of the bracken spores can also put people at risk through inhalation and drinking water carrying the spores
In addition to the concerns about sheep ticks, for farmers, the presence of bracken reduces the area of land available for grazing and makes it difficult to gather stock.
Bracken can provide great landscape interest, particularly in the autumn, but if it replaces other species that are also important for the landscape, such as heather, its impact is seen as negative.
Where large stands of bracken grow close to footpaths and bridleways the bracken can impede access and block the view of the surrounding countryside. In such situations, the overhanging fronds can bring people into contact with questing sheep ticks; this increases the risk of a tick bite and disease transfer.
The spread of the rhizomes can damage archaeological features and removal of bracken from scheduled ancient monuments is encouraged.