None of these problems are insurmountable. Enviro-nazis are ridiculous. Every time someone wants to build anything, we hear about some rare, distant relative of the tse tse fly, or the cockroach, or some weed that might be endangered by the development (be it fencing, housing, pipeline, golf course, shooting range, dam, etc.).
Fences are all along the I-70 corridor, which runs along the Eagle river in Colorado, but they have wildlife crossings. No problem. The existing fencing along the Mexican border, is 18' tall metal posts 4' apart. I saw one propaganda photo of a poor forlorn little froggy, blocked by the fence. Obviously staged somewhere else, because that amphibian would have no trouble with the 4" gaps. Wherever possible regular openings in the fence were placed also.
Here's a paragraph from a Newsweek article on the subject that was anything but sympathetic to the wall:
"...The cure is to leave key wildlife areas barrier-free, Lasky says. Before construction of the existing sections, biologists mapped out existing wildlife corridors so that openings could be placed where animals needed them. However, then-Secretary of the Department of Homeland Security Michael Chertoff waived environmental laws for construction of the fence. That meant DHS was not required to investigate the fence’s potential ecological impacts—or to even follow the maps. Wildlife openings were installed at regular intervals on some sections of the barrier, but placement was based on various factors, including whether the fence ran near residences or vegetated land. Wildlife sometimes took a back seat to other considerations. One 22-mile section of the barrier, made of solid concrete for flood control purposes, has no openings..."http://www.newsweek.com/2016/02/26/envi ... 26310.html
I have included this paragraph to show the following:
1. Wildlife crossings are
a part of the existing wall segments.There's no reason to suppose that would be any different on future sections.
2. The placement of those crossings could have been better, and, hopefully they will pay more attention to the locations recommended by the biologists.
3. The Secretary of the Department of Homeland Security, appointed by Trump, has the power to waive the environmental laws for construction of the fence.
4. There are some places where other concerns such as the mentioned flood control section, where there will be no crossings.
There also could be larger openings at known crossing areas for larger animals. Those areas would, of course, need more attention by the Border Patrol, but that's doable.
You're not going to stop the wall.