關刀溪森林生態系地震崩塌地土壤種子庫及小苗組成之研究

The Composition of Soil Seed Bank and Seedlings in the Earthquake Landslide Sites of Guandaushi Forest Ecosystem

藉由土壤種子庫與小苗動態的研究，可進一步瞭解關刀溪森林生態系九二一地震崩塌後植群之天然更新狀況。從四處崩塌地長期監測中發現，崩塌地原表土層之存留及新表土層之穩定度，對崩塌地之種子庫及小苗密度有所影響，其中以保有部分原表土層之崩塌地（L4）密度較大（55.5株/m2）。分析土壤種子庫及小苗組成物種之分布，陽性植物之種子與小苗在崩塌地與非崩塌地均佔重要比例，推測是陽性植物多產生較輕小之種子，可藉由風力傳播（昭和草、青楓、木荷及白匏子）或鳥類傳播（山胡椒），並以持續性種子庫的方式，累積留存在種子庫內。在四類生活型小苗（喬木、灌木、藤本及草本）中，在各崩塌地及其對照樣區均以喬木種所佔的比例較大。且喬木種小苗的死亡率亦低於其他三類型小苗，推測是喬木種小苗之根系較其他三類型小苗發達，可以在表土層淺薄且含水力較差之崩塌地生長。 Soil seed bank and seedling density in the landslide sites of Guandaushi forest ecosystem following 921 earthquake were monitored. Based on the inventory at 4 landslide plots, seedling density was related to the existence of the original topsoil and also to the stability of newly formed topsoil. Seedling density was highest ( 55.5 seedling / m2 ) at the plot (L4) with partial original topsoil. Most seedlings are shade-intolerant species with relatively small seeds which are easily to be dispersed by wind (Crassocephalum rabens, Acer serrulatus, Schima superba and Mallotus paniculatus ) or by birds ( Litsea cubeba ). Among the life forms ( tree, shrub, vine and herb ), the density of tree species was the highest and the mortality rate of tree species was the lowest. Seedlings of tree species are more abundant and seem to be more adaptable to landslide sites.

Soil seed bank and seedling density in the landslide sites of Guandaushi forest ecosystem following 921 earthquake were monitored. Based on the inventory at 4 landslide plots, seedling density was related to the existence of the original topsoil and also to the stability of newly formed topsoil. Seedling density was highest ( 55.5 seedling / m2 ) at the plot (L4) with partial original topsoil. Most seedlings are shade-intolerant species with relatively small seeds which are easily to be dispersed by wind (Crassocephalum rabens, Acer serrulatus, Schima superba and Mallotus paniculatus ) or by birds ( Litsea cubeba ). Among the life forms ( tree, shrub, vine and herb ), the density of tree species was the highest and the mortality rate of tree species was the lowest. Seedlings of tree species are more abundant and seem to be more adaptable to landslide sites.