Recent Topics Posters
Yost, Jenn , Barry, Teri , Rajakaruna, Nishanta , Kay, Kathleen .
Local adaptation and speciation in cryptic species of Lasthenia.
In plants, the edaphic environment is a major habitat component, and is inferred to be extremely important in plant speciation. We seek to understand the ways in which adaptation to edaphic conditions impacts reproductive isolation between closely related plant species. Jasper Ridge Biological Preserve (Stanford University), in California, USA is home to an extensive serpentine outcrop. This outcrop is occupied by two cryptic species of Lasthenia (Asteraceae), L. californica and L. gracilis, which occur in distinct regions of the outcrop. We are interested in how these two cryptic species have co-occurred together for the last 30 years across a 60-meter serpentine outcrop without apparent hybridization. We conducted a reciprocal transplant across the abrupt boundary of L. californica and L. gracilis to determine if selection maintains their distributions. We have found evidence for local adaptation in L. californica and low fitness at all sites for L. gracilis. However, where L. gracilis dominates, it has the highest relative fitness. At the boundary between the two species, fitness was intermediate for both. Soil was collected monthly to determine if the dynamic nature of soil chemistry would correlate with the timing of death in thetransplanted individuals. This study shows that subtle changes in serpentine soil chemistry can have dramatic effects on plant distributions over small spatial scales. In addition to the habitat isolation that we have found at Jasper Ridge, preliminary work suggests that pollen pistil interactions act as barriers to gene flow across the outcrop. Throughout California, we have identified a number of mixed sites where the two cryptic species co-occur and our future work will attempt to elucidate the ways in which adaptation to subtle edaphic changes can maintain or promote divergence in populations of Lasthenia.
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1 - University of California, Santa Cruz, Ecology and Evolutionary Biology, 1156 High St., Santa Cruz, CA, 95064, USA
2 - San Jose State University, Biological Science, 1 Washington Square, San Jose, CA, 95192, USA
3 - College of the Atlantic, Biological Science, 105 Eden Street, Bar Harbor, ME, 04609, USA
Presentation Type: Recent Topics Poster
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM