Preserving biodiversity alongside the threats of climate change and habitat loss is a challenge. Habitat restoration can mitigate these threats; however, identifying the material to use in restorations remains critical. This is particularly true for geographically isolated populations where isolation or fragmentation has led to the development of locally adapted seeds in situ. These populations may exhibit a ‘home site advantage’ relative to non-local seeds, making restoration ineffective if non-local seeds are used.
In this project, we are investigating variation in traits important to adaptation in Prairie Smoke (Geum triflorum); an herbaceous perennial common to midwestern prairies, but also geographically isolated on alvar habitats. Alvars are isolated limestone barrens found throughout the Great Lakes and into Manitoba that harbor many disjunct plants and experience extreme environments, ranging from flooding to early summer desiccation. This study examines the extent to which genetic differences that underlay phenotypic traits important to adaptation have evolved between prairie and alvar populations of G. triflorum. A common garden experiment using seed from 23 populations representing Great Lakes alvars, Manitoba alvars, and midwestern prairies was established in the prairie environment. This experiment will inform restoration identifying seed source material appropriate for prairie and alvar habitats.
Quantitative genetic analysis of phenotypic traits; including date to emergence, date to first flower, and number of flowers, fruits and seeds produced have been assessed following the first year of growth. There are clear differences in phenology among the three habitat types. The Great Lake alvar populations emerge significantly earlier than the prairie populations, while Manitoba alvar populations emerge at an intermediate rate. The degree of geographic isolation between prairie and alvar populations may impact these patterns. In addition, there was little difference observed in the date to first flower, however, the allocation to reproduction varied substantially among habitat types. 49% of Great Lake alvar plants flowered in the first year, while only 20% and 14% of Manitoba alvar and prairie plants flowered, respectively. The extreme alvar environment may select for increased reproductive output in early life versus the more attenuated reproductive strategy observed in perennial prairie plants. However, ongoing observations will test whether increased resource allocation to reproduction is maintained perennially or shifts over time.