福山地區次生闊葉林土壤種子庫及幼苗動態

Dynamics of Soil Seed Bank and Seedlings in the Fushan Broadleaf Forest

張乃航(Nai-Hang Chang) ； 馬復京(Fu-Ching Ma) ； 游漢明(Han-Ming Yu) ； 許原瑞(Yen-Ray Hsui)

《台灣林業科學》 13卷4期 (1998/12) Pp. 279-289

https://doi.org/10.7075/TJFS.199812.0279

摘要

為瞭解福山次生闊葉林的更新機制，我們在福山地區選擇二個地點進行土壤種子庫組成及幼苗發生與存活率的調查。土壤種子庫採用20cm×20cm小樣區分別採取枯枝落葉層及0～5cm兩層土壤，計算發芽的種類及數量。幼苗發生及存活率調查採用50cm×2m的樣帶，分別記錄樣區內幼苗發生的數量及種類，並標示之。經一年的調查；福山地區林地土壤種子庫之主要構成分子以林下耐蔭性樹種（銳葉柃木33%，野杜丹科植物28%）及草本植物(26%)為主。先驅樹種的白匏仔、野桐及山黃麻等在每一個樣區中均有發現，但數量甚少，這些種子大部份都出現於0～5cm深的土壤中。冠層植物種子多存留在枯枝落葉層之上。樟科植物的種子多呈群聚分布的情形，而殼斗科值物則沒有發現具活力的種子。
土壤種子庫的植物組成和殼斗科為主的冠層植物組成不同。鬱蔽林下種子苗存活情形以台灣黃杞最低(10%)，依次為楊梅(24%)、紅楠(29%)、香楠(41%)。在林冠孔隙及林緣地區這些種類種子苗的存活率都很高，所以我們推斷台灣黃杞、楊梅應為孔隙種，而紅楠也有偏陽的趨勢，楠木類種子苗在林下存留限制因子主要是地被植物密度及枯枝落葉的覆蓋。根據調查結果，我們可推斷，林地土壤種子庫對林地更新的影響力並不明顯，除非有較大面積的裸露地發生，影響林地更新的主要因子應是原存於林地上的幼苗，也就是林地幼苗庫。

關鍵字

土壤種子庫 ； 孔隙 ； 耐陰性 ； 好光性 ； 幼苗庫

並列摘要

The components and density in the soil seed bank, and seedling emergence arid survival rate at 2 sites in the Fushan hardwood forest were examined for 1 yr. On 2 sites, the litter layer and 0～5 cm soil layer of 20 cm×20 cm plots were used to estimate the species and density (ind/m^2) of seed content, while 50 cm × 2 m plots were used to monitor seedling emergence and survival rate. Four censuses in the year indicated that the main components of the soil seed bank were understory shade-tolerant tree species, e. g. Eurye acuminata var. acuminata (33%), Melastomataceae species (28%), and herbs (26%). Seeds of pioneer tree species could be found at 0～5 cm soil depth in every sampling plot. The seeds of canopy species were mostly found at the surface of the forest floor, but the amount was very scarce. The understory seedling survival rate was pretty low, and varied from Engelhadtsia roxboughiana (10%), Myrica rubra (24%), Machilus thunbergii (29%) to Machilus zuihoensis (41%). However, in forest gap and edge, seedling survival rate was high (above 80%) for all species found. This result indicates that E. roxboughiana and M. rubra may be gap species. The seed distribution pattern of Lauraceae species was mostly aggregated. No germinalile Fagaceae seeds were found in the study area. The species composition of the upper canopy, which was dominated mainly by Fagaceae tree species, was quite different from that of the soil seed bank. The seedling survival rate of Lauraceae species was severely restrained by ground cover and litterfall. In general, the seedling bank, instead of the seed bank, would be the major source for recruitment of upper canopy species in this forest.

並列關鍵字

soil seed bank ； gap ； shade tolerance ； photosensitivity ； sapling bank