Invasive plants
After deforesttion and unbridled urbanisation, invasive plants are the second factor contributing to the decrease in biodiversity. With the development of globalization, we import and export plants all over the planet. Some exotic plants adapt so well to their new environment that they colonize their new home to the detriment of the local species, which disappear. This phenomenon also effects the fauna, which sees its natural biotope transform and in which the animals no longer find the conditions for their development.
These invasive plants are often well known to gardeners as we find them in our gardens and along the roadside. Take for example the summer lilac or butterfly bush (Buddleja davidii) from China, which is perfectly adapted to our climate, or the Silver Wattle (Acacia dealbata) from Australia which has invaded the Mediterrranean coast. And who hasn't heard of the Caulerpa taxifola, the invasive Mediterranean seaweed !
Invasive plants often have the knack of spreading rapidly and over long distances. They often take advantage of an instability in the natural environment where they arrive, which is often due to human acticvity ( deforestation, pollution, etc..), to install themselves permanently. Some are almost impossible to get rid of, like the Japanese knotweed (Reynoutria japonica) which develops a widespread root system consisting of rhizomes. And we also find invasive plants in preserved areas.
Different agencies which monitor these problems exist and they develop ways of limiting the damage to the original biotopes.
The exotic invasive plants most known to gardeners (list incomplete) :
- Acacia dealbata, Silver Wattle
- Buddleja davidii, butterfly bush
- Carpobrotus, ice plant
- Cortaderia selloana, Pampas grass
- Impatiens glandulifera, Himalayan Balsam
- Opuntia, Barbary fig