Large grazing animals like elk, mule deer and pronghorn need big spaces. So residential development on open rangeland can have a huge effect on them.
Researchers at the University of Wyoming recently figured out a way to minimize the effects of development. They measured the shortest distance between adjacent houses and any associated structures, then paired these “widths” with observed movements of mule deer, elk and pronghorn.
When houses are built too close together, animals cease to pass through remaining gaps. The narrow spaces between buildings act like natural topographic barriers, forming bottlenecks that animals avoid. This indirect habitat loss is much greater than that from building footprints.
The specific distance that triggers avoidance depends on species and habitat type. Some animals steer clear of gaps between houses up to two miles wide, while others may move through a corridor as little as a quarter of a mile wide.
Researchers have made a publicly accessible width calculator to help plan housing developments in ways that maximize space for large grazers to move.
For example, placing houses strategically within each parcel instead of building in the middle of a parcel can increase the critical width metric from a quarter of a mile to nearly two-thirds of a mile.
That allows many animals to continue to pass between houses, reach adjacent large tracts of undeveloped habitat and continue their natural seasonal migration and habitat use patterns.
This Earth Note was written by Diane Hope and produced by KNAU and the Sustainable Communities Program at Northern Arizona University.
