Physaria filiformis grows in
limestone glades and
outcrops of bare
bedrock in southwestern Missouri and northwestern Arkansas.
Wildfire is important in the maintenance of the limestone glade habitat and even more so its surrounding
ecotones. Fire is the mechanism that keeps these habitats open and free of large and woody vegetation that shade out small annuals. Fire prevents
ecological succession in the open habitat where the plant grows. As the health of the local
ecosystem depends on fire, the practice of
fire suppression has caused the degradation of the habitat. When fire is prevented, woody vegetation moves in, covering the glades and blocking the light from reaching this small plant. This encroachment of surrounding vegetation is a main threat to the species. Other threats include
off-road vehicles, limestone mining, and urban development.
Invasive species of plants have been introduced to the habitat, including
Bromus tectorum, a competitive
grass. The plant may be affected by
grazing, trampling, and other disturbance, but these threats are mild because the plant can tolerate light disturbance. == Conservation ==