Gold-edged gem (Schinia avemensis) COSEWIC assessment and status report: chapter 8
Limiting Factors and Threats
The only major limiting factor for the Gold-edged Gem appears to be the amount of suitable habitat, and perhaps the fact that this habitat occurs more or less in small, widely disjunct patches. The most serious threat is the loss of active, blowing sand as a result of dune stabilization which has occurred at a rapid rate in the past. There are no other obvious imminent threats to the Canadian populations of Gold-edged Gem, which have managed to persist until now.
Overzealous or careless pesticide use could impact some populations, but because most open dune habitat is not associated with forest or cropland, impacts from this source are considered a low risk. Of more concern is overgrazing by livestock at colonies on leased and private lands. Under extreme conditions, when forage is in short supply (i.e. during prolonged drought conditions), livestock could conceivably decimate or eliminate a colony by consuming the flowering heads of sunflowers where eggs and larvae are concentrated.
Invasion and stabilization of dune habitats by introduced weeds, such as sweet clover (Meliotis sp.) and spurge (Euphorbia sp.), could accelerate dune stabilization or replace colonies of the larval host plants. Extensive dense patches of sweet clover (Meliotus sp.) were observed covering significant portions of the Spirit Dunes adjacent to areas currently occupied by Gold-edged Gems (Anweiler, personal observation, 2004).
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