Variation in Adaptive Traits and Seed Zone Evaluation of Showy Milkweed (\u3cem\u3eAsclepias speciosa\u3c/em\u3e)

Monarch butterfly (Danuas plexippus) populations are imperiled and in review for listing under the Endangered Species Act. Among many contributors to the decline is the loss of breeding, migratory, and overwintering habitat. Showy milkweed (Asclepias speciosa) and other obligate milkweeds are essential for monarch reproduction and have thus been cornerstones of monarch habitat restoration efforts in the Intermountain West. However, many potential restoration areas lack convenient seed sources to supply prospective efforts. Furthermore, because certain populations may be better adapted to specific local climates and selective pressures, the introduction of non-native, poorly adaptive genotypes may have negative consequences for restoration efforts and milkweed-dependent species. We used a genecological approach to identify adaptive traits among 35 showy milkweed populations from the Intermountain West to inform seed transfer zones for A. speciosa. We used morphological measures and plant growth data in conjunction with remotely sensed climate data to identify putative adaptive traits and determine how they relate to local climate variation. Here we present the results of our analyses and their implications for classifying showy milkweed seed transfer zones and maximizing restoration and conservation benefit for monarch butterflies