Some scientist have proposed that American Indian warfare played a critical ecological role by regulating and maintaining both the numbers and distribution of bison and other big animals of the West before descendants of Europeans settled it Basically, according to this "war zone" theory, Indian hunters were so proficient that in an individual tribe's homeland, populations of big game like bison and elk seriously declined and in some cases disappeared But in several big buffer zones between warring tribes, where hunters were loath to spend much time lest their enemies attack them, big game found more safety and flourished These no-man's-lands functioned, in effect, as game preserves
In fact, the plenitude of bison and other game in the war zones reflected the status of the area as a buffer zone, where war parties of various tribes or nations were ever at hand, and anyone hunting, processing and drying meat might be killed by enemies.
On a more fundamental level, the war zone theory implies that humans are a force outside nature, that their impact is unnatural and therefore undesirable. However, humans are an integral part of nature, one of many forces that have long kept the natural world in a constant state of flux.