Abstract Detail

Ecology

Finch, Jessamine [1], Valdes, Imeña [2], Havens, Kayri [3].

Latitudinal Variation in Reproductive Phenology Impacts Fitness of Common Milkweed Provenances.

The value of ecological restoration is contingent on the appropriate sourcing of plant materials to establish a plant community and restore ecological function. Long-standing recommendations to source plants close to the restoration site (local) are now being challenged by strategies aimed at maximizing adaptation to future climates and evolutionary potential. However, intraspecific variation in phenology among seed sources has direct effects for trophic interactions, including insect pollination. To investigate the effect of seed source on plant phenology, pollination, and fitness, we compared populations of Asclepias syriaca (L.) collected along a 460-mile latitudinal gradient in the Midwest U.S. in a centrally located common garden. Persistent phenological and phenotypic differences were found across multiple growing seasons. Northern sources flowered earlier, were shorted at maturity, and demonstrated considerably less interannual variation in phenology than southern sources. Pollinator visitation was highly correlated with flowering phenology, and southern sources, which flowered later, produced more viable fruits and less aborted fruits than northern sources. These results suggest southern sources may perform better than local or northern sources under restoration settings. In addition, populations may demonstrate decreased fruit production under climate change, with implications for population persistence and colonization of new sites. However, assisted gene flow through the introduction of seed from southern populations could introduce adaptive phenological traits, and expedite adaptation to changing climates. Additionally, these results suggest mixing of seed sources for restoration and habitat creation could greatly expand flowering windows, with clear implications for pollinator conservation.

1 - Native Plant Trust, Conservation, 180 Hemenway Road, Framingham, MA, 01701, United States
2 - Plant Biology and Conservation Program, Northwestern University, 2145 Sheridan Road, Tech F315, Evanston, IL, 60208, USA
3 - Chicago Botanic Garden, CONS SCI DEPT, 1000 Lake Cook Road, Glencoe, IL, 60022, United States

Keywords:
phenology
milkweed
provenance
Pollination
restoration
seed sourcing
climate change
intraspecific variation
Local adaptation
monarch butterfly.

Presentation Type: Oral Paper
Number: EC06002
Abstract ID:716
Candidate for Awards:Ecological Section Best Graduate Student Paper