Grand coulee owl-clover (Orthocarpus barbatus) COSEWIC assessment and status report: chapter 10
Limiting factors and threats
At one time, overgrazing was probably the most serious threat to Orthocarpus barbatus in Canada. Grassland habitats in the Bunchgrass Biogeoclimatic Zone in the southern Okanagan Valley have been seriously degraded over the years due to the prolific invasion by alien species such as Acroptilon repens, Bromus tectorum and Centaurea diffusa. Alien species, especially newly arrived species, are still a major threat to O. barbatus in the South Okanagan Grasslands Protected Area, especially since grazing leases still exist within the Protected Area.
The major habitat threat to Orthocarpus barbatus at this time is through increased land conversion. This land development includes orchards, vineyards, golf courses and housing. All of these have probably eliminated potential O. barbatus habitat. Two of the populations, on the slopes of Mount Kruger, are presently within a few hundred metres of an actively expanding housing development on private property (Figure 5).
A third population, near “Veronica Lake”, is on private land. At the present time, this area is utilized as rangeland and is heavily infested with alien species. Since large tracts of private land in the Okanagan Valley are extremely desirable for vineyards or housing development, the potential for destruction of this population is high.
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