Population dynamics of the spiny country rat (Niviventer coxingi) in a subtropical montane forest in central Taiwan

Population dynamics of the spiny country rat Niviventer coxingi were studie d by mark-recapture methods from January 1982 to May 1983 in a subtropical montane forest at Chitou, central Taiwan. The population density was < 8 ra ts/ha. The annual pattern of population fluctuation was characterized by su mmer increase, autumn peak and spring decline. Adult recruits occurred most ly in summer and autumn 1982, whereas young rats joined the population as t hree cohorts: winter 1981, summer 1982 and winter 1982. Growth patterns dif fered between winter and summer cohorts, which was attributed mainly to the slow body weight increase in summer cohort males. Males, either adult or j uvenile, survived the winter better than females, resulting in the shorter lifespans and the lower number of females in the population. Life-history t raits in female N. coxingi, i.e. short reproductive lifespan, few litters p er life time and prolonged maternal care, along with the low breeding inten sity, rendered the number of females the limiting factor for population inc rease. However, females may improve the survival and maturation of their of fspring by prolonged maternal care.