[fosc] Pallid Manzanita

Ralph Kanz rkanz at earthlink.net
Tue Jan 10 12:26:18 PST 2006


Today I received the population numbers for Pallid manzanita.  Surveys completed in the mid 1980's estimated the Sobrante Ridge population at 1,700 to 2,000 plants.  The same survey found 2,400 to 2,700 plants at Huckleberry Preserve.  

Last year the East Bay Regional Park District mapped all the plants at Sobrante Ridge, Hucklebery, Redwood and Sibley. The result is a population at Sobrante Ridge estimated at 333 plants.  121 plants were counted and the balance of the number is based on density because many plants are in a thick poison oak stand.  747 plants were counted in a adjacent to the park at Huckleberry.  Surveys performed by FOSC members found the population in the watershed was just over 100 plants and had declined about 50 percent over the last 20 years.  

Based on these new numbers, the total pallid manzanita population (this is total for everywhere on this planet) is about 1200 plants.  Twenty years ago the estimate was close to 5,000 individuals.  Last week another plant was impacted by construction activities in the watershed.  How long will they last?

Ralph Kanz
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