Could an isolated cutoff valley sustain a diversity of animals alongside humans?

Question

My world has an isolated valley between high mountains like the Himalayas that is practically cut off from the world by high elevation mountains and steep cliffs. The valley is about five miles in length and two miles in width. One river and various streams run through the valley. An isolated tribe of humans numbering about 100 to 150 live in the valley scattered in small villages of ten to fifteen. The humans have lived there for over 200 years. The humans take care to diversify their sources of food, and to not take more than they need. Their culture values preserving nature. The right side of the river is relatively uninhabited with forests that are left mostly undisturbed.

The humans domesticate a yak-like animal, herd goats, and hunt small game. They also may grow barley like the Tibetans if it proves there may not be many animals.

I think it is likely that the humans would have killed off the wolves or major predators, but would other animals be able to reproduce at a rate to maintain their populations if the human population hovers around 100?

The only animals that may be able to travel into the valley over the mountains would likely be birds or mountain goats.

Answer 1

Its possible but not likely. Humans would shape the environment to suite their own ends, even if they have a strong culture of working with nature.

Removing the Apex predators, and even numerous lower order predators/herbivors would be task number one, and does not even require the humans to kill them off directly, simply to out compete them for resources. Its awfully slim pickings at the top. This would reduce the dangerousness of the habitat for both humans, and their crops/herds. However it would also remove many negative feedback loops that keep the local ecology in check.

Land would be cleared to ensure crops/pastures. This land would be prime land close to water. This would further strain the eco-system as Humans make poor watering hole companions to most species, and that land would no longer be available for use by most wildlife for any sort of living.

As for examples you can take Native Americans, or the Australian Aboriginals. Both of these cultures value working with nature, both societies will ward off predators, and both societies architectured their environments.

• Native Americans cleared land, grew crops, and watered them
• Australian Aboriginals burnt forests to encourage new growth, and ensure a larger grassland, and new growth forest in which to hunt/forage.

Not to say that 200 years would be long enough for these forces to have played out in that's roughly six to ten generations, but to claim that the humans are in balance here would be a comment made far to early.