The Phenology of Space: Spatial Aspects of Bison Density Dependence in Yellowstone National Park

This population has been intensely monitored for almost four decades. The analysis of long-term spatio-temporal data from 1970-1997 supports the following conclusions: 1) Even though the Yellowstone bison herd exhibits an extended period of what appears to be linear growth, this pattern can be explained with classical density dependent dynamics if one realizes that perhaps the primary response of the herd to increased density is range expansion. 2) Several spatial aspects of social behavior in the YNP bison may be behavioral adaptations by the bison to environmental changes.

These behavioral strategies may buffer, temporarily at least, bison population dynamics from the immediate repercussions of possible environmental stress and habitat deterioration. 3) Bison ecological carrying capacity for YNP is on the order of 2800 to 3200 animals. 4) There do appear to be indications of changes in the bison dynamics that are associated with increasing use of sections of the interior road system in the winter. 5) The possibility of habitat degradation is indicated.