Description- Member of the lily family
- Bulbous perennial
- It has an single basal leaf, 1-2’ long
- 2-3 flowers at the top of 20” tall stems.
- Living 10 years, it may spend a third of it's life in dormancy as a bulb.
- Often don't reproduce until 5 years old.
- Bees are the main pollinator
- Flowers from May to June.
- How to identify it:
"Each three-petaled blossom looks like a shallow bowl made of furry kitten ears, light green with dark red lines and spots on each petal, tufted with white curly hairs. The erect three-pronged stigma and six dark red stamens hover in the center of the flower like Cerberus riding a starfish. The whole affair is held aloft on a wiry stalk one foot high, with several flowers per stalk" -Geoffrey Coffey (http://www.madrono.org/san-francisco-landscape/journalism/mariposa-lilies-and-monoliths-on-ring-mountain.html#.VQMurY7F8pU).
The characteristics vary by deme:
Serpentine bunchgrass community
Serpentine does not support large, rapid growth among plants. Most plants that do grow on serpentine are slow growing and small. Therefore the this ecosystem appears open, without tree canopy or much under story vegetation, and is sometimes referred to as a serpentine prairie. The community on Ring mountain occurs 460' above sea level. Other plants that are part of the community include serpentine reedgrass, Tiburon buckwheat, Tiburon paintbruch, and Marin dwarf-flax (California Native Plant Society 1988).
- Serpentinite locations on campus
- More plants that grow on Serpentine: Serpentinite Flora
Geographic & Population Changes
Calochortus tiburonensis is endemic to Ring mountain. Meaning it only occurs in along the ridge of these 123 acres that make up the mountain. It has evolved to withstand the stressful serpentine soils here. This means that it can not spread to other areas and it destined to remain only on Ring mountain, if it doesn't become extinct.
In fact the soil chemistry on Ring mountain varies widely by location causing 7 distinct patches and each deme is acclimated to survive in the specific soil make up in which they occur (Swope 2013). The different patches can cross pollinate, but the resulting offspring may have lower fitness depending on whether it inherited the genes it needs to survive in the specific soil type that it grows in. This has led to inbreeding depression.
Inbreeding depression is the reduced biological fitness in a given population as a result of inbreeding (http://en.wikipedia.org/wiki/Inbreeding_depression)
According to Fiedler’s study in 1987 only 0-11% of the individuals successfully produced seeds among the plants that began the process of reproduction, 36%-64%, over the course of three growing seasons (Fiedler 1987).
Number of flowering plants per year (California Natural Diversity Data Base 1996).:
1989- 5,783
1990- 3,443
1991- 19,875
Calochortus tiburonensis is currently listed as threatened
Vulnerable due to it's rarity
Because this is the only population of this species, and it's so small, it can easily be wiped out by stochastic events. Therefore it is listed as threatened due to the risk of natural and man-made disasters such as fire. Additionally, because this species is incredibly close to highly developed land it is at a high risk of disturbance from people visiting the area for recreation and for a chance to see (and possibly collect) the beautiful, rare plant.
Recovery Plan
Because it is endemic to Ring mountain the plan recommends continuous protection and management with no option of delisting it.
Strategies:
- Protect each subpopulation with a 500 foot buffer
- Reduce external influences and allow expansion of subpopulations.
- Aqcuire land where new subpopulations are discovered
- Protect uninhabited land that might be recolonized or is habitat for pollinators or seed dispersers.
Develop and implement a management plan that includes:
- Monitoring each subpopulation every 3 years
- Monitoring flowering and vegetative individuals
- Strategies to minimize threats and identify new threats
- Educational outreach program
Collection of seeds for seed banks in Center for Plant Conservation certified botanic gardens is a priority, but must be done carefully by selecting less than 5% of the seed crop and/or only when there is high seed production.
Research of appropriate management practices is of lower priority. This includes analyzing the effects of grazing and fire, developing propagation techniques, and studying the species dependence on bumble bees among other things.
Sources:
Elam, R. Diane. Goettle, Bradley. Wright, David H. U.S. Fish and Wildlife Service. Sacramento Fish and Wildlife Office. "Recovery Plan for Serpentine Soil Species of the San Francisco Bay". U.S. Fish and Wildlife Service. September 30 1998. Bethesda, Maryand. <http://ecos.fws.gov/docs/recovery_plan/980930c_v2.pdf>
Swope, Sarah. "Gene flow and local adaptation in a variable environment". 2013. <http://www.sarahmswope.com/site/page/research>
Image sources in order of appearance:
1. http://www.summitpost.org/ring-mountain-open-space-preserve/790730
2. http://www.summitpost.org/ring-mountain-open-space-preserve/790730
3. Jessica James (Google earth)
4. http://treve.photoshelter.com/image/I0000nd7kWbpJmzo
5. https://cdfgnews.wordpress.com/tag/sea-otters/
6. http://www.sarahmswope.com/site/page/research
7. https://naturetime.wordpress.com/2012/05/07/ring-mountain-rare-tiburon-mariposa-lily/ring-mountain-tiburon-mariposa-lily/
8. https://shellkoonse.wordpress.com/
9. Jessica James (Google earth)
10. Jessica James (Google earth)
11. Jessica James (https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=65216&inline=1)
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