It ensures that amendments are made carefully and thoughtfully (Apex)
The primary significance of the Mayflower Compact was that it established a rule of law in the Plymouth colony before the settlers even arrived, since it was drafted and signed aboard the Mayflower itself.
The tiny invaders being discussed in the article are plants. They are considered invaders because they came from other countries, but are now threatening the native plants. People brought them in because they wanted to make their gardens and yards beautiful because the plants are very rarely found locally.