Threats to coastal cress
A Lepidium flexicaule
Little is known about the abundance and distribution of coastal cresses during pre European times. However, numbers have definitely declined over the last 150 years.
Reasons for this decline are complex, but have been linked to the following causes:
- Browsing: Coastal cresses are eaten by domestic stock, and introduced wild mammals.
- Pests: Garden pests, especially white rust. White butterflies, cabbage aphids, slugs, and snails also attack wild coastal cresses.
- Over-collecting by professional and amateur botanists.
- Habitat deterioration caused by coastal development, farming, and erosion.
- Loss of animal species: Seabirds and seals are a key factor in their ecology. The decline of cress species can be linked to a decline in these animals.
- Natural events: Severe storms and climatic events such as El Nino can wipe out isolated populations.
- Competition: Coastal cresses are vulnerable to competition from invasive plants.