臺灣北部福山地區亞熱帶雨林種子雨之研究

The Seed Rain in a Subtropical Rain Forest, Fushan, Northern Taiwan

張楊家豪(Chia-Hao Chang-Yang)

指導教授 ： 謝長富

國立臺灣大學/生命科學院/生態學與演化生物學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.00795

摘要

為了解臺灣北部亞熱帶雨林的種子雨在時間及空間上的變化，於福山地區的25公頃樣區中，設置87個面積為0.5m2、網目為1mm之種子網，並嘗試探討該森林中主要物種之繁殖策略與更新機制。自2002年9月開始至2004年3月止，每週收集掉落於種子網中之花、果實、種子等部位，為期共80週。所有收集到之樣本分別鑑定其種類並分為成熟果實、成熟種子、未成熟果實、果實附屬物、果實碎片、花等六類，計算各類別之數量，同時將所有收集到的成熟種子以切下胚法檢視其種子活性，而後將所有樣本烘乾秤重。

研究期間共收到37科58屬67種之落花落果、10356顆種子；就2003年1月至12月一年之資料而言，共收到落果0.26 t/ha、落花0.11 t/ha、6877顆種子，重量上以烏來柯最重，種子數則是以江某為最多。而各類別在時間上的變化頗大，落花集中在3 ~ 5月與6 ~ 7月掉落，未成熟果實集中在4 ~ 5月與8 ~ 12月掉落，果實碎片集中在10 ~ 11月掉落，成熟果實與種子集中在4 ~ 6月與9 ~ 12月掉落，果實附屬物則伴隨成熟果實與種子掉落。此外，未成熟果實於2003年9月因受颱風影響而有一極端高峰，明顯較其他各類別之數量高出釵h。

依主要物種之落果期，可區分為4 ~ 6月、9 ~ 12月與不規則掉落三群，落果期4 ~ 6月的物種有5種，不規則掉落的物種則僅有3種，其餘物種之落果期多在9 ~12月間。整理各物種結實情形，烏來柯與長尾栲為潛在果實數最多的種類，然其結實成必v不到0.1%。結實成必v最高的種類為九芎，其次為

關鍵字

種子雨 ； 繁殖策略 ； 亞熱帶雨林 ； 福山

並列摘要

The purpose of this study is to understand the temporal and spatial variation of the seed rain in a subtropical rain forest of Fushan, northern Taiwan, and try to probe into the reproductive strategies and regeneration mechanisms of dominant tree species.

A total of 87 0.5-m2 seed traps were placed in a 25-ha plot established in Fushan Subtropical Rain Forest. All seeds, fruits, seed-bearing fruit fragments, and flowers > 1 mm in diameter falling into the traps have been collected every week from Sept. 2002 to Mar. 2004. All samples were identified to species and separated into mature fruits, mature seeds, capsules, fruit fragments, immature fruits, and flowers. The viabilities of all mature seeds were also investigated in the meantime.
All seeds were counted and sorted into 67 species, belonging to 37 families and 58 genera. There were 6877 seeds collected from 87 seed traps, and the biomass of falling fruits and flowers was 0.26 t/ha and 0.11t/ha during 2003. The highest biomass of the seed rain belongs to Limlia uraiana and the largest amount belongs to Schefflera octophylla. The onset and duration of seed rain varied considerably among each species in this forest and that can be categorized into three types: (1) Apr. to Jun., (2) Sept. to Dec., and (3) fruit falling all the year. There are only 3 species whose fruits fall all year round, 5 species during Apr. to Jun. and others during Sept. to Dec.

Species with the largest potential fruit amount was Limlia uraiana, and the next was Castanopsis carlesii, but the successful fruiting rates of these two species were less than 0.1%. Species with the highest successful fruiting rate was Lagerstroemia subcostata, and the next was Glochidion acuminatum. A large proportion of fruits are immature fruits in species. Percentage of seed viability is quite different among main species, and ranges from 26% to 99%.

The reproductive strategies of the dominant forest tree species are quite different from each other. Species like Schefflera octophylla and Glochidion acuminatum produce lots of seeds but with worse quality to overcome the hazards in each stage of fruiting. On the other hand, Machilus thunbergii, Machilus zuihoensis, and Litsea acuminate produce better quality seeds for their regeneration. The successful fruiting rates of Limlia uraiana and Castanopsis carlesii are extremely low. More researches are needed to understand the role of seed rain in their regeneration.

並列關鍵字

reproductive strategy ； Fushan ； subtropical rain forest ； seed rain

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