臺灣中部低海拔次生闊葉林土壤種子庫組成之研究：以臺中大坑地區為例

Abstract

土壤種子庫是植物重要的更新方式，種子通常有比植物成株較強的忍耐能力，埋藏在土壤中逃避干擾、病害或是取食，因此土壤種子庫常在植被受到干擾、破壞後的退化生態系統之更新中扮演關鍵的角色。本試驗以種子發芽法調查大坑地區現生次生林土壤中種子的組成與儲量，以推測土壤種子庫在次生林更新與演替中扮演之角色。本研究共記錄52科123屬159種種子植物，總計共萌發15,514株種子苗，有7株種子苗未能歸類鑑定；換算為單位面積種子密度約6,550 ind./m2。59.5%的種子於發芽試驗開始一個月內即萌發；種子數以臺灣山桂花最多，共有1,665 ind.；植物生長型分析顯示，不論是在種數或是種子儲量均以草本為主。種子庫物種組成有49種為馴化植物，占總物種數31%，種子儲量佔35.75%，種數與儲量在種子庫佔有相當大的比例，對大坑地區次生林演替與更新的影響需更進一步研究探討。將調查所得資料進行雙向指標種分析，並對照降趨對應分析的結果，另與各樣區現存植群資料進行對應分析、各樣區環境資料典型對應分析，探討土壤種子庫組成趨勢與生育地環境間的關係。結果顯示，土壤種子庫與地上部植物社會物種組成間的相關性低，探討其原因是為土壤種子庫其中含有較多先驅種的種子，且樣區間物種組成的相似性高於上部植群；典型對應分析結果可以看出人為干擾及環境潮濕程度對土壤種子庫組成影響最劇。

Soil seed bank is an important regeneration strategy for plants. Seeds buried in the soil to avoid interference, disease or feeding that tend to have stronger tolerance than the plant unities. Therefore, the soil seed banks play an important role to the disturbed vegetation, destruction of degradated ecosystem regeneration. This experiment used seed germination method to survey the soil seed composition and content of the secondary forest in Dakeng area. The results can estimate the role of the soil seed banks in the secondary forest regeneration and succession. In this study were recorded 52 families 123 genera 159 angiosperm species.Totally there are 15,514 individual seedlings were sprouted. 7 Individual of seed can not classified. The seed density is 6,550 ind./m2. 59.5% of seeds were germinating within the first month of germination testing. The most amount seed of species is Maesa perlaria, about 1,665 ind. According the growth form (tree, shrub, liana, herb), the species number and density of the herbaceous plant growth form was priority. In the seed bank there are 49 naturalized plants, which about 31% of the total number of species, and seed contents in occupy 35.75%. The naturalized plants occupied a large proportion of the soil seed banks. The effects of succession and regeneration to secondary forest need further more research. The investigated data was referred to the TWINSPAN analysis and compared the results of DCA. Combined analyzation with standing vegetation population of each plots by CA; Combined analyzation with Environmental factors of each plots by CCA. Discussed how the trend of Composition of the soil seed bank to the relationship between habitat environment. Found of that Soil seed bank and aboveground vegetation composition of species was low correlation. The reason was that soil seed bank contained the amount of seeds of pioneer species. And the similarity index between plots higher than the standing vegetation.The result about analyzation of CCA figured that the degree of human disturbance and environmental wet effect on the composition of the soil seed bank in Dakeng Area.