中興大學東勢林場土壤種子庫組成研究

Comparison of soil seed bank in Tungshih Forest Station of Naional ChungHsing University

本研究於中興大學實驗林管理處所轄東勢林場，應用種子發芽法進行次生林、楓香（Liquidambar formosana）造林地及廢棄果園等3種林地之土壤種子庫組成與儲量調查。地上部植群共記錄55科108屬130種維管束植物。土壤種子庫共發芽2,127株幼苗，平均種子密度為3,501.2粒/m2，共記錄31科57屬64種|菊科（Compositae）、禾本科（Gramineae）及桑科（Moraceae）是物種數最多的前三科。山黃麻（Trema orientalis）等前10名種子儲量物種總和超過土壤種子庫總量的75%。草本植物是土壤種子庫物種數最多的生長型，喬木、草本和灌木植物的種子儲量分別各約佔種子總量的1/3。3種林地的土壤種子物種數依序為廢棄果園、造林地及次生林，種子儲量依序為造林地、廢棄果園及次生林。歸化植物種數於地上部有13種，土壤種子庫有14種，分別佔種數的10.83與21.88%。歸化植物在土壤種子庫的種子儲量約佔總量的15.04%，在廢棄果園的物種數與種子儲量比例都是最高。東勢林場地上部種子植物與土壤種子庫物種組成的Sørensen相似性指數為0.32，在3種林地的高低依序為廢棄果園、造林地和次生林，Sørensen相似性指數高低與干擾程度有關。主坐標軸分析結果顯示，地上部植群與土壤種子庫樣區排列在第一軸的兩側，顯示兩者的物種組成差異大|第2軸大致依植群類型排列，顯示各樣區的地上部植物組成對土壤種子庫種類仍有所影響。研究顯示，東勢林場濫墾地回收後的楓香復育造林有助於恢復森林物種多樣性的生態功能。本研究結果可以提供復育造林和森林生態系經營的重要參考依據。

This study was conducted at Tungshih Forest Station of National Chung Hsing University's Experimental Forest. Seed germination was used to investigate the soil seed bank compositions and seed reserves of three forest types, namely secondary forest, Liquidambar reforestation area, and abandoned orchard. The aboveground vegetation exhibited 55 families, 108 genera, and 130 species of vascular plants. A total of 2,127 seedlings were germinated in the soil seed bank, including 64 species, 57 genera, and 31 families, with an average seed density of 3,501.2 seeds/m2. Most species were from the Compositae, Gramineae, and Moraceae families. The top 10 species, including Trema orientalis, occupied >75% of total seed reserve. Herbs were the dominant plant growth form, comprising most species in the soil seed bank, and seed reserves of trees, herbs, and shrubs each occupied approximately one-third of total seed abundance. The highest species number of soil seed banks was abandoned orchard, followed by those from Liquidambar reforestation area, and finial, secondary forest| whereas, the highest abundance of seed reserves was secondary forest, followed by those from abandoned orchard and Liquidambar reforestation area. In total, 13 and 14 naturalized species were noted in the aboveground vegetation and soil seed banks, respectively, accounting for 10.83% and 21.88% of all species, respectively. The naturalized plant seed reserves accounted for approximately 15.04% of the total seed abundance. In terms of both species number and seed reserves, the highest proportion of naturalized plants was noted in abandoned orchard areas. The Sørensen similarity index of seed plants between aboveground vegetation and soil seed banks was 0.32| the similarity of vegetation type was the highest in the abandoned orchard, followed by the Liquidambar reforestation area, and finial, the secondary forest. The principal coordinate analysis results demonstrated that data points of aboveground vegetation and soil seed banks were distributed on both sides of the first axis, indicating the species composition for both differed considerably| whereas vegetation types distributed along the second axis, demonstrating the effects of species in aboveground vegetation on soil seed bank composition. Thus, the reforestation of Liquidambar formosana, after illegally cultivated land was taken back by Tungshih Forest Station, is conducive to restoring the ecological function of forest species diversity. This study provides critical information for reforestation and forest ecosystem. management.