1. Ann Arbor’s natural ecology is most threatened by invasive plant and insect species that were brought over by European settlers or shipping, and now thrive in an ecosystem devoid of natural predatory or climatic counterbalances.
2. Garlic Mustard, a cooking herb planted by Ann Arbor’s European settlers, can cope with Michigan winters so well it will often keep growing under a layer of snow.
3. The reason campus’s squirrels often have chunks of fur missing is because a lack of predation allows old and disease-ridden squirrels to survive.
4. More prairie grasslands characterized Ann Arbor’s natural landscape before invasive foreign plants took over.
5. An insect called the Emerald Ash Borer has nearly obliterated Michigan’s ash tree population after being accidentally transferred from Asia to Detroit in shipping crates.
6. Ecological managers set controlled fires in forest areas to clear the floor of undergrowth and dead leaves blocking sunlight and nutrients from the soil – a technique Michigan’s native people carried out regularly before European settlement.
7. The Wild Indigo Dustywings butterfly is one of Ann Arbor’s most threatened animal species. Its natural nectar source has vanished from the area, and the source it’s adapted to is an invasive plant that would normally be removed.