The term bioinvasion means that a plant or animal is not native in their current location and often spreads to a dangerous degree which is harmful to it's new environment, to the economy and to human health. An example of this is the Asian longhorned beetle which infected and damaged millions of acres of hardwood trees, as it was introduced in the United States.
It can be one of two things.
First, it can be due to global warming.
Second, it can be due to the rotation of the sun. When the sun rotates, it can change it latitude causing it to hit at different points onto different areas of the world.
D) Territory
For example Puerto Rico is its own country but is territory of the United States.