Cyclic fluctuation in number of habu trimeresurus flavoviridis caught on amami oshima japan 2
Minakami, K.; Huzii, M.; Tanaka, M.
Japanese Journal of Herpetology 8(3): 95-99
The existence of cyclic fluctuation in the number of habu, T. flavoviridis, caught on Amami Oshima was examined with a computer. The spectral analysis represented statistically periodical properties of a time series. The yearly fluctuation of the habu number caught from 1954-1977 were regarded as a realization of a stationary time series. The spectral density was estimated by 2 methods: Blackman and Turkey's estimate and an autoregressive model. Through the latter method, peaks appearing at about 4 and 8 yr cycles were found. The existence of these cycles was ascertained by simulation. A change of sugarcane yield at a given time negatively correlates with the number of captured habu 7 yr later.