Shrinking Populations
As a masters student at San José State University in the Environmental Studies Department, my research focused on the mating system of the endangered Erysimum teretifolium (Ben Lomond wallflower). The chair of my research committee was Dr. Rachel O'Malley in the Environmental Studies Department at San Jose State University. I also worked with Dr. Will Russell from the Environmental Studies Department at San Jose State University, and Dr. Justen Whittall from the Biology Department at Santa Clara University.
MASTERS THESIS
A Promiscuous Wallflower: The Rare Zayante Sandhills Endemic Erysimum teretifolium (Brassicaceae) Benefits from Outcrossing
Abstract: The Zayante sandhills ecosystem of Santa Cruz County, California, contains a rich mosaic of plants and animals adapted to unusual soils and microclimates. In this environment, local adaptation of populations is expected to lead to greater endemism and outbreeding depression. Anthropogenic fragmentation has further isolated populations, however, which paradoxically could result in inbreeding depression. One of these plants, Erysimum teretifolium (Ben Lomond wallflower) is an endangered endemic herb in the Brassicaceae family. This study assessed genetic mixing across remnant patches of E. teretifolium in order to estimate the effects of fragmentation and the reliance on pollinators. A captive breeding colony was established from seeds collected from four locations across the Zayante sandhills and used in 161 pollinations. Individual allele frequencies were measured using microsatellites, and pollination potential was evaluated through insect camera trapping. Self-pollinations produced 6.5 times fewer seeds than outcrosses. There is no evidence of outbreeding depression. Results suggest that there is a potential for inbreeding depression; however, it is possible that self-incompatibility and reliance on pollinators for outcrosses across geographic divides may be buffering effects. Implications for managers include evidence that geographic origin of individuals may not be critical for reintroduction; however, conservation of the pollinator community should remain a priority.
Erysimum teretifolium visited by Euphydryas chalcedona.
ZAYANTE SANDHILLS
Zayante Sandhills habitat at San Lorenzo Valley Water District – Olympia Wellfields. Due to high levels of diversity, the Zayante Sandhills are considered the Galapagos Islands of Santa Cruz County.
The Zayante sandhills is a threatened environment with a unique diversity of plants and animals that are highly adapted to their unique soils. Many flowering plants depend on local pollinators for reproductive success. The sandhills have a patchy distribution and, due to the high levels of diversity, have been considered the Galapagos Islands of Santa Cruz County. Urban development, sand mining, and recreation have further reduced the already rare Sandhill populations to critical levels. Research on plant-pollinator relationships is fundamental to understanding the role insects play in the movement of genetic traits in small plant populations such as E. teretifolium.
Ben Lomond spineflower
(Chorizanthe pungens var. hartwegiana)
Santa Cruz monkeyflower
(Mimulus rattanii ssp. decurtatus)
Pussypaws
(Calyptridium monospermum)
PUBLICATIONS
Melen M, Herman J, Lucas J, O’Malley R, Parker I, Thom A, and Whittall J. 2016. Reproductive success through high pollinator visitation rates despite self incompatibility in an endangered wallflower. American Journal of Botany 103(11).
Melen M. May 2014. A promiscuous wallflower: the rare Zayante sandhills endemic Erysimum teretifolium (Brassicaceae) benefits from outcrossing. Master's Thesis, Environmental Studies Department, San José State University, San José, California, USA.
PHOTOS
