| Summary: | 碩士 === 國立臺灣大學 === 森林環境暨資源學研究所 === 97 === Although numerous mechanisms have been proposed to explain the coexistence of species in highly diversified communities, the niche/neutral controversy remains unsettled. Testing empirical evidence against theoretical mechanisms in explaining coexistence is important for understanding community ecology. Woody plants diversity pattern at local scales (< 1 km2) in tropics was firstly demonstrated as supports for neutral theory against niche driving assembly theory. Recent spatial analyses of tropical forest dynamic plots showed empirical evidences supporting the neutral theory at > 20 m scale but niche assembly theory at < 20 m scale. Thediversity pattern in subtropical forests might differ from the tropical plots; however, no study in subtropical forests has been carried out. This study aimed to explore the woody plants diversity pattern in the 25 hectare Fushan Subtropical Forest Dynamic Plot in northern Taiwan and elucidate the role of inter-specific interactions in different spatial scales. Through individual species-area relationship (ISAR) analysis and Monte Carlo simulation, the species-area patterns from individual view were estimated; as such, every woody species was distinguished as a diversity accumulator, repeller, or neutral species. These species specific characteristics then were treated as implication for the strength of competitive interactions in the study site. The results showed that the influence of negative interactions among woody species in this subtropical plot was greater than other studied tropical plots. All the 52 examined woody species at the Fushan plot behaved as diversity repeller within a 50 m scale and did not show scale-dependent neutral behavior. In conclusion, the high prevalence of diversity repeller suggests that negative inter-specific interactions were strong in this study site. Therefore, niche driving assembly processes may play a more important role in structuring the woody plants diversity pattern of Fushan subtropical plot than that in tropical plots. The results provide important basis for further investigation on the mechanisms of such negative inter-specific interactions in the subtropical forests.
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