What invasive species are
All over the world, there are programs that kill animals of these species in large numbers. The text asks: what are these programs trying to achieve?
An example: ducks in Europe
In southern Europe, an environmental program killed American ruddy ducks. They were breeding with a duck species native to the region. The ducklings from these crossings were seen as a threat to the native species, which might "disappear" by mixing with the other one.
Notice: the American ducks were not causing more suffering to other animals. The only problem was that they were mixing with the valued species.
What the program wanted
It's clear that the goal wasn't to reduce animal suffering or deaths. It was to make sure only the species environmentalists value, like the native ones, existed in that place.
What if it were humans?
Goals like "keep only the natives of a certain group" or "prevent mixing between groups" would be seen as horrifying if applied to humans. They're only accepted because the victims are animals.
This shows these programs fail the impartiality test: the people who approve of them only do so because they know they won't be the victims.
In short
- Invasive species are species from elsewhere that change an environment.
- In the case of the ducks, the goal was to prevent species from mixing, not to prevent suffering.
- These goals would be unacceptable if applied to humans.