Invasive species

2. 2.6 million of this species occupy 28% of Australia
3. removal of bark from a tree, leading to the trees death
5. Species of penguin found on Middle Island, that was threatened by foxes
6. a lithospheric process that is caused by goats and rabbits overgrazing and/or burrowing
7. form of control that relies on using 'natural' products such as predators or diseases
10. an invasive plant that chokes waterways
11. the system that controls the entry of organic matter (such as plants) into a country
14. an invasive herbivore that causes erosion by burrowing
16. a dog that is used to hunt invasive species and protect penguin and livestock populations
17. a species that is not native to an environment
19. a method of controlling invasive animals through poisoning
21. form on control where humans actively hunt and remove invasive species
22. a plant species that is potentially toxic to horses and other livestock

1. invasive plant species that can be controlled by goats, and whose seeds don't usually survive digestion by goats
4. the variety of plant and animal species in an ecosystem
8. where a species lives
9. a species introduced by Europeans that is a predator to many natural species
12. the act of completely wiping out an introduced species
13. a species that was accidentally transported to another place by boats or another vehicle
15. form of control using poisons
18. an environment that includes many interconnected plant and animal species
20. a species originally introduced to control pests, but become invasive itself