Impacts of Habitat Loss, Modification, and Fragmentation. Impacts related to the Covered Activities may include loss, modification, or fragmentation of DSL Habitat. As described above DSL presence is correlated to sand dunes with blowouts, and when present, shinnery oak (Xxxxxxxxxx et al. 2011; Xxxxxxxx et al. 2013). Removal of shinnery oak vegetation has been correlated with reductions in DSL abundance, though DSL have been documented in areas subsequent to removal of shinnery oak (Xxxxx et al., 1997). Because vegetation including shinnery oak affect dune geomorphology, the removal of shinnery oak “fails to meet the basic needs of the [DSL]” according to FWS (See 77 Fed. Reg. at 36,892). Disturbance of DSL Habitat and development of infrastructure on the landscape may fragment DSL Habitat into smaller patches. In disturbed landscapes with shinnery oak dunes the DSL may occur in relatively lower abundances centered in areas of remaining shinnery oak dunes with relatively large blowouts (Xxxx and Xxxxx 198; Xxxxxxxxx and Xxxxxxxxxx 2011; Xxxxxx et al. 2017; Xxxxxx et al. 2019). The lowered relative abundance and general avoidance of modified landscapes (e.g., roads) may affect or disrupt the dynamic of populations but predicting extirpation is impossible at this time as DSL have been detected in oil fields that are 40 years old (Xxxx and Xxxxx 1998; Xxxxxx et al. 2017; Xxxxxx et al. 2019). DSL are not known to disperse across large expanses of unsuitable habitat, thus fragmentation of DSL Habitat that results in isolation of DSL population may threaten its genetic diversity as gene flow may be maintained by cumulative short distance movements of individuals among populations (Xxxx et al., 2009). Because the Mescalero- Monahans Shinnery Dune System is spatially and temporally dynamic with complex interactions between wind, water, sand, and vegetation it is difficult to predict how disturbance and development will disrupt the dynamics of the dune-blowout ecosystem. Areas with active dunes devoid of vegetation will have different responses to disturbance compared to areas with semi-stabilized dunes anchored by stabilizing vegetation such as shinnery oak due to differences in local sand supply, wind erosion, water availability and vegetation (Muhs and Xxxxxxxx 1995, 2001). Though effects of disturbance on open sand dunes in inland systems is largely unknown, inferences may be drawn for vegetated dunes from previous studies and anecdotal observations of shinnery oak removal and effects to DSL populations. Chemical re...
