Given that 95% of the mule deer that winter in the Atlantic Rim Project Area (ARPA) are
migratory (Sawyer 2007), sustaining current mule deer populations will require functional
migration routes remain intact. Prior to 2000, conserving migration routes had not been a top
management concern for agencies because there had been no large‐scale habitat alterations in
the ARPA or Baggs Herd Unit, (e.g., Bureau of Land Management [BLM] 2000a, BLM 2000b) and
the landscape had remained relatively unchanged. However, the recent approval to develop
2,000 gas wells at a spacing of 8 per section and improve or construct approximately 1,000
miles of road and pipeline (BLM 2006) will result in large‐scale habitat changes that could
potentially impact mule deer migration routes in the ARPA. While disturbances associated with
gas development may alter habitat selection and distribution patterns of wintering mule deer
(Sawyer et al. 2006), it is unclear at what level of gas development migration routes are
affected. Nonetheless, accurate delineation of migration routes prior to gas development and
identification of high‐use migratory segments would allow managers to develop proactive,
rather than reactive, management prescriptions. Absent specific knowledge of migration
routes, it is difficult for agencies or industry to develop gas resources in ways that minimize
potential impacts to mule deer migration. Additionally, detailed information on migration
routes can be used to identify habitat characteristics of migration routes and study the
potential effects of proposed development on migration.