The effect of human settlement on the density of moose in northern Alberta

The objective of our study was to determine the net impact of human settlement on moose (Alces alces) at a large scale. Our study area was northern Alberta, Canada, which is divided into a White Zone in which agriculture is permitted and where most human settlement is concentrated, and a Green Zone which is comprised of boreal forest with minimal human settlement, Moose densities were determined using a 1993 moose census that covered almost all of northern Alberta. We found a linear decline in the density of moose with increasing distance from the White Zone. The median density of moose in the White Zone was 0.40 moose/km(2) compared with 0.25 moose/km(2) in the Green Zone. Within the White Zone both human settlement and the density of moose declined with increasing latitude. While access is generally assumed to have a negative influence on moose, we found that at the regional scale the density of moose was positively associated with the density of roads. The regions with the greatest moose densities also had the greatest intensity of licensed hunting. We hypothesize that the observed association between settlement and the density of moose reflects a causal relationship and we provide arguments to support our supposition.