| Summary: | 碩士 === 國立中興大學 === 水土保持學系所 === 103 === The construction matching with vegetation is often used for the regulation of landslide in Taiwan to achieve the primarily rapid coverage and establish favorable basis for successive succession. Nevertheless, invasive plants change with landslide regulation areas, and aggressive plants among alien species are often dominant species with slow species turnover rate that they might retard the natural succession.
Nine vegetatioing areas under the governance of Nantou Forest District Office of Forestry Bureau are selected for the vegetation succession investigation. The vegetation composition and succession are analyzed to evaluate the role of alien species in the succession process and the possible effects of dominant alien species. Palaeontological Statistics data analysis software is utilized for Principal Component Analysis of vegetation communities, and Correlation Analysis of external environment factors and vegetation composition are used for understanding the characteristics of alien species.
Total 77 families 256 species of vascular plants are recorded in the research area, and alien plants account for one-fourth of all species. The gramineous family (13%) and composite family (10%) are the two most dominant families. The areas with dominant Miscanthus sinensis var. glaber and Miscanthus floridulus tend to have higher proportion and importance of indigenous species than other investigation sites. Correlation Analysis results reveal that species richness is correlated with slope, pH value and annual average temperature and there is a significant negative correlation between alien species proportion and total cumulative rainfall. The insignificant correlation between species richness and alien species proportion is different from the hypothesis about diversity resistance hypothesis(DRH); and, the correlation between average naturalness and alien species is also insignificant, presenting that it does not conform to the hypothesis about propagule pressure. Among investigation sites, Panicum maximum grows dominantly in the investigation site (S1changhua) seriously interfered with humans, and Bidens pilosa radiate in site (S7dakeng) still expands in the late phase to cause succession retardation.
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