Sagehen Creek Field Station

15 Nov, 02 AM - 30 Jun, 10 AM

Variation in ploidy is common among plants, and has been hypothesized to alter the ecological tolerances of species. However, only a handful of field studies have tested for niche differentiation among polyploids and their diploid progenitors. Using a combination of field transplant studies and GIS niche modeling, I am investigating niche differentiation in the context of climate change in the Claytonia perfoliata complex. This group of California native annuals is characterized by diploid and polyploid populations which exhibit distinct geographic ranges and habitat associations, suggesting that polyploid and diploid members of the complex differ in their ecological tolerances and may differ in their responses to predicted climate change. Field transplant experiments will consist of planting an identical common garden design at a series of sites ranging from the Central Valley (Davis) to high elevations in the sierra (Sagehen Reserve) to test for local adaptation to climatic conditions. Populations used in the common garden will come from collections of Claytonia perfoliata, Claytonia parviflora and Claytonia rubra made between Davis and Lake Tahoe in the vicinity of the American River and Yuba River watersheds. Approximately 500 plants will be established in each garden prior to December 15th by planting individual seeds glued to toothpicks. In order to prevent establishment of non-local genotypes, plants will be harvested prior to flowering and seed set, at the date of first visible inflorescence production. To ensure that plants are removed prior to flowering, plants will be monitored weekly for signs of flowering beginning in February (low elevations) or when plots are snow free (Sagehen). Risk of contamination by gene flow is low in this group, as the flowers are 'pseudo-cleistogamous' and plants are generally selfing, but will also be prevented by harvesting when inflorescences are first produced. To further minimize potential establishment of non-local genotypes, soil will be removed from the vicinity of any un-germinated plantings. Gardens will be established in disturbed areas to minimize impacts of soil removal. Growth rates and biomass at date of first flowering will be used to estimate fitness (based on regressions relating biomass at first flowering to seed set). Garden design will consist of 7 individuals from 15 maternal families from each of five cytoypes (low elevation hexaploids of C. parviflora (1) and C. perfoliata (2), sierra foothill diploids of C. parviflora (3) , mid elevation tetraploids of C. parviflora (4), and mid to high elevation populations of C. rubra (5). For ease of surveying, plants will be established within a series of 1m by 0.5m plots containing 50 plants, for a total of 10 plots and an experimental ?footprint? of 5m2.

Visit #13868 @Sagehen Creek Field Station

Approved

Under Project # 9050 | Research

Climatic adaptatation and niche differentiation in the Claytonia perfoliata polyploid complex

graduate_student - University of California, Davis

Reservation Members(s)

Patrick McIntyre Nov 15, 2007 - Jun 30, 2008 (229 days)

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Day Use 1 Nov 15, 2007 - Jun 30, 2008