I mentioned in the comments to the last post that treating entry-level employees as interchangable and disposable is a bad idea if said employees are actually doing critical and unsupervised work.
Unfortunately, a lot of environmental firms do churn through their entry-level folks. They send them out into the field with minimal training for weeks (months) on end, don't pay them overtime when the entry-level folks are regularly working 70-80 hour weeks (and the base level pay isn't that great either), and have laughably small project budgets. The idea is to keep folks in indentured servitude for two years, and if they actually stick it out, graduate them to doing 100% office work.
I have some experience with these firms, and let me tell you how much quality work you get out of folks who are out in the middle of nowhere, criminally underpaid to begin with, and are acutely aware that their 40 hours of paid work ended Wednesday afternoon and it's now Friday. The fact that their 120% billability enables the higher-ups to have super-low billability is not exactly a big motivator.
The other issue is that these firms treat fieldwork as monkey science and a trial to get through and never do again. Fieldwork produces the fundamental data that your entire enterprise is based on. If you have poorly collected data, it makes all your fancy models and technical arguments worthless. And you may get away with shitty work for a while, but unless you're doing utterly rote reports, someone is going to catch you. It may be a regulator, a concerned citizen (if you're representing Big Bad Industry), or more likely, it will be a consultant for another company that's trying to shift blame for their mess onto you. And when you're on the stand (figuratively or literally) and the easy stuff is wrong, you lose all credibility and you can kiss your big contracts goodbye*.
*That's wishful thinking - most upper level management is expert at tap-dancing around inconvenient problems and convincing the client that the real problem is that they need more money, stat. But I'm an idealist.