Population dynamics and considerations for the conservation of the rare Cycas fairylakea in China

Quantitative dynamics and viability of a rare and wild Cycas fairylakea population were studied with a time-specific life table,a Leslie matrix model and a survival function in order to provide scientific guidance for its protection.The results of the timespecific life table show that this C.fairylakea population suffered a high death rate in three age classes,i.e.,age class I(0-15 years), V(61-75 years)and VI(76-90 years).The Leslie matrix model suggests that the number of plants would decline from the present 1613 to 59 per hectare in 150 years.Furthermore,the viability analysis indicates that seedlings have the highest mortality density rate and that middle-aged plants(i.e.,61-75 years,76-90 years)have high mortality density rate and hazard rate.These conditions affect natural regeneration of the population and lead to a lack of seedlings which in turn causes the extinction of the population.An in situ conservation of the population should be established and protection measures taken as soon as possible.