Small-flowered tonella (Tonella tonella) COSEWIC assessment and status report: chapter 9

Special Significance of the Species

Tonella tenella, in British Columbia, occurs in a restricted habitat type, the Garry Oak ecosystem of southeastern Vancouver Island. In this vegetation type, which has been greatly reduced by urban development in the last one hundred years, a high number of rare species are found.

Furthermore, the populations are at the northern extent of their geographic range. Peripheral populations are sometimes genetically and morphologically divergent from central populations and may have an evolutionary and ecological significance out of proportion to the percentage of the species they represent (Mayr 1982; Lesica and Allendorf 1995). The protection of genetically distinct peripheral populations may be important for the long-term survival of the species as a whole (Lesica and Allendorf 1995).

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