Analyzing Vegetation Dynamics of the Broad-leaved Secondary Forest by Species Abundance Models at Mt. Showchu in the Hue-Sun Forest Station

種豐富度模式應用於惠蓀林場小出山闊葉樹次生林之植群動態分析

It was little known about the vegetation dynamics of the broad-leaved secondary forest at Mt. Showchu in central Taiwan. In this study, species abundance models such as geometric series, logarithmic series, truncated log normal distribution, and broken stick model were applied to analyze the change in biodiversity of 1983 to 1997. It showed no significant difference on the species richness indices for α and λ of broad-leaved secondary forests among the various periods. Furthermore, the logarithmic series was the best fit model for the outcomes of three different thinning treatments applied to the target experimental area in four investigation periods, followed by the geometric series and then the truncated log normal distribution. The broken stick model hardly fit the actual dynamics. Therefore, it was found that after 13 years of the experiment, the three thinning treatments had some minute effect on the dynamics of the vegetation structures in the plots. Most plots were in the middle and later stages of the succession, whereas other plots approached the climax. 本研究藉由幾何序列、對數序列、截斷對數常態分布模式、折枝模式等四種不同性質的種豐富度模式，剖析1983～1997年間，惠蓀林場小出山之三種疏伐處理的闊葉樹次生林之植群動態。研究結果得知各時期之不同處理間的α、λ的種豐多度指數並無差異；此外，以最符合之種豐富度模式而言，不同時期之三種處理多最符合對數序列，其次為幾何序列、截斷對數常態分布模式，僅少數樣區最符合折枝模式。整體而言，1983年（處理前）乃至1997年（處理後13年），此三種處理之各樣區的植群結構僅具細微變動，多數樣區處於演替中後期階段，而部分樣區已達極盛相。

本研究藉由幾何序列、對數序列、截斷對數常態分布模式、折枝模式等四種不同性質的種豐富度模式，剖析1983～1997年間，惠蓀林場小出山之三種疏伐處理的闊葉樹次生林之植群動態。研究結果得知各時期之不同處理間的α、λ的種豐多度指數並無差異；此外，以最符合之種豐富度模式而言，不同時期之三種處理多最符合對數序列，其次為幾何序列、截斷對數常態分布模式，僅少數樣區最符合折枝模式。整體而言，1983年（處理前）乃至1997年（處理後13年），此三種處理之各樣區的植群結構僅具細微變動，多數樣區處於演替中後期階段，而部分樣區已達極盛相。