1. It's already been proven border fences are bad for the environment.

The border already has some fenced off with barbed wire, steel, or chains. Just the construction itself to put fences up ruined a lot of the environment around it. One group of species that have been affected, in particular, is the Mexican gray wolf. Just in 2016, there were only 113 in the United States and about 3 dozen on the other side of the border. This already is leading toward their extinction.

2. There are many animals that could be affected and results could be deadly for them.

Some of the animals include mountain lions, Texas horned lizard, Plains blind snake, and Rio Grande chirping frog. About 346 species could lose access to their habitat. This could lead to the risk of extinction of these animals. Fencing and walls that have already been built have already cost North America their rare animals.

3. Animal migration patterns could be affected.

With a wall, many animals won't be able to migrate for season changes properly. Many animals won't be getting across to migrate. If they can't migrate, chances of getting the food, shelter, and mates they need are slim. For example, the Peninsular bighorn sheep migrates between California and Mexico and if the wall is built, that would end.

4. Flooding could occur.

Depending on how the wall is built, it may not allow for proper water flow. This means it could cause flooding in certain areas. Under the George W. Bush administration, 700 miles of fencing was put up. In southwest Arizona, 15 foot high wire mesh fence caused debris build up just during a short thunderstorm. The floods got up to 7 feet high in some areas.