Fifteen years dynamics of woody floristic community in a subtropical rain forest, Lanjenshi plot, southern Taiwan
Date Issued
2006
Date
2006
Author(s)
Yeh, Ding-Hong
DOI
zh-TW
Abstract
Abstract
In 1990, a 3-hectare permanent forest plot was established in Nanjenshan. All free-standing woody plants ≧1cm dbh were identified to species, measured, and mapped. The second and third censuses were completed in 1997 and 2005. Over the three censuses, 131 species and 45,317 individuals were recorded.
In this thesis, forest-wide recruitment, mortality, growth, population size and basal area change were compared in both census intervals. This comparison was also conducted in habitat and species levels in order to elucidate the changing pattern of this forest.
The population was continuously decreased in both census interval, but the degree was much higher in the second interval (-1.65%yr-1) than the first interval (-0.18%yr-1). The basal area increased 10% in the first interval, but decreased 4% in the later one. The annul recruitment rate decreased and the annul mortality rate was elevated at the same time, both kind of change contributed to the high-degree population decreasing in second interval. The growth rate was lower in the second interval than in the first interval.
The forest-wide changing patterns were also appeared in four kind of habitat type which were assumed to be different in wind exposure extent. Nevertheless the changing pattern was more obvious in Windward habitat which exposed more to north-east monsoon wind, and became obscure according to the wind exposure extent. So, we suggest the windy environment maybe became worse and it might be one of the possible explanation of population decreasing.
In species level, most species have the same changing patterns with total forest. 61 of 76 species had lower recruitment rate in the second census interval, 57 species had higher mortality rate in the second interval. There were more species that had negative population change in second interval than first. And the basal area change shared the same trend with population change.
In 15 years, most species had higher degree of population decreasing in Windward habitat, include species that distributed only in Windward habitat like Ilex lonicerifolia, but had lower degree of population decreasing in Intermediate habitat. Moreover, some species had population increasing in Leeward habitat. Species that sustained or expanded their population size in Windward habitat were species that have more tough leaf and were more suitable for windy environment in physiology like Podocarpaceae nageia, Podocarpaceae podocarpus, Cyclobalanopsis championii. Windward Specialists which had better wind-resist ability underwent population growth, and less wind-resist Windward specialists underwent population shrinkage. The different performance of Windward specialists support the assumption that windy environment became worse.
Subjects
森林動態
欖仁溪樣區
南仁山
新增
死亡
干擾
forest dynamics
Lanjenshi plot
Lanjenshan
recruitment
mortality
disturbance
Type
other
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