Phenotypic Variation in Adaptive Traits Among Western Populations of Showy Milkweed (\u3cem\u3eAsclepias speciose\u3c/em\u3e)

Monarch butterfly (Danaus plexippus) populations have suffered extensive declines due to habitat loss and fragmentation in wintering, migrating, and breeding ranges. Urbanization and intensive agricultural practices have reduced populations of milkweeds which monarchs depend on for reproduction. With increasing conservation concern and a prospective Endangered Species Act listing, there is increased motivation for habitat restoration projects that enhance milkweeds. Our project seeks to describe variation in adaptive traits and phenology among populations of showy milkweed from the Western US. We conducted common garden experiments, in which we propagated and grew individuals from 36 populations ranging from California to South Dakota. We used remotely sensed climate data in conjunction with morphological measures and plant growth data to identify variation in adaptive traits and correlate them to elevation and climate variation. Here we present the results of our analyses and their implications for defining seed transfer zones for showy milkweed in the context of monarch butterfly habitat restoration