Is It Acceptable to Let a Species Go Extinct in a National Park?

I once was asked whether it was okay to allow a species to go extinct in a national park. My gut response was no, but I had not thought about the question seriously: whose park and where, and would the extinction have direct or indirect effects on the ecological community? Perhaps I might have couched a reply by suggesting that it was okay for some species to go extinct in some parks but not in others. Whether a single unanimous response fits all possibilities is unclear. Here I address the question by suggesting how preemptive measures might be used to forestall species losses, and I follow up with a real-world case of how an imminent loss can be circumvented. This latter point is highly relevant because it concerns not only the looming extirpation of a species from a national park but also an ecological process of national and international importance: the longest overland mammal migration across the vastness between Tierra del Fuego and Toronto.