Mechanical treatments - ground-level. In some situations, the use of mechanical treatments may be more appropriate than manual techniques, e.g., for controlling dense stands of tall fescue (Festuca arundinacea) or for releasing competition around numerous Xxxxxxx’x lupine plants and/or patches of native plants. Mechanical maintenance techniques include mowing, line trimming, grubbing, girdling trees, raking, and chain saw or mechanical removal of woody species. Mechanical maintenance activities in occupied Fender’s blue butterfly habitat will primarily be conducted when the lupine and nectar plants have completed seed production and the butterflies are in diapause (i.e., mid-August through February), unless otherwise specified in a site-specific plan where the techniques and locations of the treatments will have no effect on listed species. Mechanical treatment to remove woody vegetation, exotic species and competing plants may occur on up to one-half of the occupied Fender’s blue butterfly habitat on an enrolled property each year. One hundred percent of the area of those sites may be mechanically treated over time. When mowing occupied Fender’s blue butterfly habitat, mowers will be set to a blade height high enough to minimize the risk of gouging the ground, harming low-stature native plants, and impacting butterfly larvae (generally at least 10 to 15 cm (4 to 6 inches). Tractor mowers that are rubber-tracked are preferred over wheeled mowers whenever practicable. Mowing may be conducted throughout sites with Fender’s blue butterflies after lupine senescence and before lupine re-emergence (generally August 15 to March 1). After the butterfly flight season but before Xxxxxxx’x lupine senescence (generally June 30 through August 15), tractor mowing may occur no closer than 2 m (6.6 feet) from the nearest Xxxxxxx’x lupine plants. Mowing with hand-held mowers may be implemented during the Fender’s blue butterfly flight season (generally May 1 to June 30) as long as a buffer of at least 8 m (25 feet) is maintained between the mower and any individual of a Xxxxxxx’x lupine plant. Early spring tractor mowing (i.e., March 1 through May 15) may be used for management purposes only in habitat unoccupied by the butterfly. At unoccupied butterfly sites with listed plants, the preferred timing for mowing will be in the fall and winter after listed plants have senesced for the season (generally August 15 through February). Spring mowing may be implemented at unoccupied sites with listed plants if needed ...
