Six criteria were chosen to assess the importance of habitats based on the annual life cycle of the Herd.

1. Energy Balance:The energy balance of a productive caribou cow can be estimated for all periods of the year. The habitat that sustains a cow during the time of year when she is using more energy than she is taking in is of concern.

   Rationale- Animals disrupted from normal activity or displaced from normal ranges are not able to compensate, energetically, on a daily basis if they are normally in an energy deficit for that time of year.

2. Reproductive Contribution:Those habitats that are occupied during the time of year critical to reproduction are of concern.

   Rationale- Although all periods contribute to the potential growth rate of the herd, some periods have a higher contribution, both in terms of birth and mortality. For example, late summer and fall are important for pregnancy and birth rates within a year, and calving habitat in early summer is important to the survival of calves.

3. Tolerance to Disturbance:Areas occupied when animals are least tolerant to disturbance are of concern.

   Rationale- The potential for displacement to other ranges or disruption of normal activity patterns is greater during periods when the Herd displays greatest reaction to human disturbance.

4. Escape Requirements:This refers to the use of areas mainly to avoid or escape from deep snow, predators and insects. Areas that are used for escape are of concern.

   Rationale- These habitats offer protection for the Herd during critical times in its life cycle and directly influence survival and growth.

5. Intensity of Use: Over the last 20 years, enough information about the Herd's distribution has been gathered to assess use of specific areas throughout the year. Areas receiving the highest use (measured in "caribou-days"), for whatever reason, are important.

   Rationale- Many factors influence the distribution and abundance of animals in a certain region. This criterion simply says that those regions that consistently contain high densities of animals should be considered important.

6. Alternatives Available:The movements and distribution of the Herd over the last two decades have revealed times of year when a particular area is utilized almost exclusively with no alternative habitats apparently selected.

   Rationale- Displacement from, or disruption of access to these areas could affect the productivity of the herd.