Chapter 11 The Madison Headwaters Elk Herd: Stability in an Inherently Variable Environment

Theme While the elk herd that winters on the northern range of Yellowstone National Park has been the subject of almost continuous investigations since the inception of the park, the elk herd that occupies the Madison headwaters area in the central portion of Yellowstone has received much less scientific attention. This is a particularly interesting population for the study of regulatory processes because the elk remain within the confines of the park year‐round and, thus, are not subjected to harvest by human hunters. Historic records also suggest that the herd was not targeted by market hunters during the 1800s nor managed by the National Park Service through intensive culling, as was common for ungulates occupying the northern range until 1968 when the Park Service adopted the natural regulation policy (Cole 1971, 1983). Hence, the dynamics of this herd have not been influenced to any appreciable extent by human manipulations other than the extirpation of wolves from the Park in the early 1900s. This portion of Yellowstone is also subjected to harsh winter conditions with periods of intense cold temperatures and deep snow pack in most years. These conditions provide an excellent opportunity to study the influence of density‐dependent and density‐independent factors and their interactions in regulating population processes in an ungulate herd. In this chapter, we present the results of an intensive demographic study of this population that was conducted just prior to the reestablishment of wolves.