Do Showy Milkweed (Asclepias speciosa) Leaf Characteristics Respond to Environmental Conditions?
Additional Funding Sources
This project was made possible by the NSF Idaho EPSCoR Program and by the National Science Foundation under Award No. OIA-1757324.
Abstract
Monarch butterfly populations have declined since the 1970s due to habitat loss and fragmentation caused by human activities. Monarch conservation efforts call for the obligate host plants, milkweeds, to be replenished across the Western US. By quantifying phenological and morphological variations of Showy Milkweed across the Intermountain West, our study will delineate seed transfer zones to maximize restorations success. Successful habitat restoration will require germplasm that is adapted for target restoration environments and seasonal phenology. We recorded leaf length, width, surface area, specific leaf area, and trichome densities from ten individuals among 35 populations raised in a common garden to inform photosynthetic capabilities, water use-efficiency, and defense against herbivory. By modeling relationships among leaf characteristics, climate and known herbivore responses, we can restore milkweed that is both best adapted to the environment, and best suited to host Monarch larvae. As existing monarch butterfly populations represent less than 1% of historic abundance, effective conservation is needed to restore numbers to sustainable levels. Here we present our methodological approach for assessing leaf characters, and evaluate the implications that leaf traits have for both plant fitness and host plant suitability for monarch butterflies.
Do Showy Milkweed (Asclepias speciosa) Leaf Characteristics Respond to Environmental Conditions?
Monarch butterfly populations have declined since the 1970s due to habitat loss and fragmentation caused by human activities. Monarch conservation efforts call for the obligate host plants, milkweeds, to be replenished across the Western US. By quantifying phenological and morphological variations of Showy Milkweed across the Intermountain West, our study will delineate seed transfer zones to maximize restorations success. Successful habitat restoration will require germplasm that is adapted for target restoration environments and seasonal phenology. We recorded leaf length, width, surface area, specific leaf area, and trichome densities from ten individuals among 35 populations raised in a common garden to inform photosynthetic capabilities, water use-efficiency, and defense against herbivory. By modeling relationships among leaf characteristics, climate and known herbivore responses, we can restore milkweed that is both best adapted to the environment, and best suited to host Monarch larvae. As existing monarch butterfly populations represent less than 1% of historic abundance, effective conservation is needed to restore numbers to sustainable levels. Here we present our methodological approach for assessing leaf characters, and evaluate the implications that leaf traits have for both plant fitness and host plant suitability for monarch butterflies.