Description: As stated in the HAF about mid-scale spatial extents “Second-order habitat descriptions are linked to bird dispersal capabilities in population and subpopulation areas” (page 11, Stiver et al. 2015). A mid-scale boundary is not intended to represent a (sub)population boundary; rather, it provides a spatial extent that is appropriate for assessing habitat characteristics that may influence second-order habitat selection, such as patch size and connectivity (see Table 2 in the HAF TR). The scale at which that occurs is driven by the dispersal distances/behavior of the birds in the (sub)population. A mid-scale boundary may include only part of or an entire (sub)population depending on the size of the population in the area of interest. Likewise, the mid-scale boundary may need to extend beyond a (sub)population boundary to adequately assess indicators of second-order habitat selection. The extent of the boundary is more important than the boundary line itself. The mid-scale boundary should encompass the fine-scale boundaries and the site-scale assessment areas. Mid-scale boundaries are required to calculate and examine mid-scale habitat indicators as defined in the HAF, such as habitat availability, patch size and number, patch connectivity, and density of anthropogenic disturbance within patches. The boundary provides an ecologically-driven geographic extent at which these metrics will be measured.
Copyright Text: Bureau of Land Management and Idaho Department of Fish and Game