Invasive species - Unwelcome visitors
One of the unfortunate consequences of our efforts to change this world is the impact alien, non-native species can have.
Rhododendrons are covering mountainous areas of Ireland excluding all other forms of vegetation. Sitka spruce dominate many skylines. Grey squirrels are happily eradicating native reds. American mink hunt and kill anything their size allows and various forms of pondweed are killing our great limestone lakes. Zebra mussels are having an impact as yet unknown on our waterways, as are American crayfish and chub.