Why is bracken fern considered invasive in some places?

Bracken (Pteridium aquilinum) is considered an invasive species in many regions due to its aggressive growth habits and its negative impact on local ecosystems and agriculture.12

The plant is a highly effective colonizer of open and disturbed ground, spreading through an extensive network of deep-set rhizomes that can reach lengths of up to 400 meters (1,300 feet). Once established, these rhizomes make the plant nearly impossible to eradicate.12

Bracken is problematic for several reasons:
* Competition: It grows vigorously, shading out other plant species, including those of conservation concern.12
* Agricultural Impact: The plant renders land unsuitable for livestock grazing.12
* Toxicity: Its leaves contain poisonous and carcinogenic compounds, which can be harmful to animals and humans.12

Because of these factors, bracken is widely regarded as one of the world’s worst weeds.12