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US Fish & Wildlife Service FieldNotes

SACRAMENTO: Showy Indian Clover (Trifolium amoenum) Reintroduction Project

Region 8, July 9, 2007

By Valary Bloom, Sacramento FWO
In October 2006, endangered showy Indian clover (Trifolium amoenum) was reintroduced to Point Reyes National Seashore, Marin County, California, by Diana Immel, rare plant ecologist, and Valary Bloom of the Sacramento Fish and Wildlife Office (SFWO) in coordination with the National Park Service.  The tall, annual native clover was once widespread in grasslands with coastal influence in the counties surrounding San Francisco Bay.  Listed in 1994 as an endangered species, almost all known populations have been extirpated as a result of habitat conversion.  The single remaining wild population is restricted to the front yard of a private residence.  The purpose of the reintroduction was to spread the risk of extinction over additional locales, which would be protected in perpetuity on public land. 

The site at Point Reyes National Seashore, D Ranch, is undisturbed coastal prairie with soils and plant communities similar to the adjacent E Ranch where J. Burtt Davy collected the species in 1900.  Hand scarified seeds were planted in small groups along twelve transects following environmental variables (aspect, elevation, moisture) existing at six different sites spread over a wide area.  A monitoring trip in June 2007 revealed that over half of the 728 seeds planted germinated, the remainder having mainly been predated by snails, insects and possibly small mammals.  Later herbivory was due to larger mammals such as rabbits, gophers, deer, and elk.  Plants that survived herbivory were subject to desiccation due to the low rainfall conditions this year.  Seventy-seven plants survived to the end of the growing season and all but one of those produced flower heads.  Though seeds had not completely developed by the monitoring visit, an estimate of future seed production was made using data from a previous study.  Over half of the expected seed production (449 seeds) was expected to be produced in one area which differed from the other transects in that it had a relatively higher elevation and a gentler slope.

 

This project, funded by the SFWO Recovery Branch, exemplified a mutually beneficial partnership with the National Park Service and was intended as a pilot project to determine microhabitats most suitable to Trifolium amoenum survival and seed production.  The project may gain additional funding in future years to supplement the existing seedbank at those sites where fitness was highest.  In fact, the project’s success will truly be revealed in the next couple years when we will more accurately be able to determine the contribution to the seedbank and resulting germination rates.

 

The hope is that with refined site selection and more typical rainfall, the populations of this endangered plant may flourish!

 

Contact Info: Scott Flaherty, , Scott_Flaherty@fws.gov