| Summary: | 碩士 === 國立臺灣師範大學 === 生命科學研究所 === 97 === To approach the effects of anthropogenic activities and
environmental factors on local native and naturalized plant communities,
this study was conducted in the Northern Taiwan. A total of 2,242
quadrats in 1m2 of 100 plots in 1km2 were sampled according to
designated habitat types. Selected anthropogenic and environmental
factors were obtained, and biodiversity indices were applied on the field
data for further analyses. According to the results, habitat types with
higher anthropogenic activities (e.g. roadside, cemetery, crop field) were
highly invaded. Plant invasions were facilitated by anthropogenic
activities (including both diversity and intensity) as well as environmental
factors. Significantly positive relationships were found between
anthropogenic activities (e.g. landscape heterogeneity, exploitation
intensity, and agriculture factor) and the biodiversity and dominance of
naturalized species. On the other hand, exploitation intensity was
negatively correlated to native biodiversity. Propagule pressure and
disturbances created by anthropogenic activities may be the major
mechanism facilitating biodiversity and dominance of naturalized species.
II
Environmental factors including elevation-temperature and precipitation
factors were negatively correlated to naturalized biodiversity but
positively correlated to native biodiversity. Native—exotic richness
relationships were also examined under different plot characteristics at
same spatial scale. Negative relationships (more native less exotic) were
found at plots with lower anthropogenic activities, while positive
relationships (more native more exotic) were found at plots with higher
anthropogenic activities. The mechanisms related to the native—exotic
relationship transformation may be biotic resistance in negative
relationships and abiotic factors including landscape heterogeneity in
positive relationships. This result demonstrated the new evidence of how
anthropogenic activities affect plant invasions and also made the current
discussions in native—exotic richness relationships more comprehensive.
These results can provide valuable direction in the management of
naturalized plants.
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