金門浦邊地區海茄苳族群結構之研究

POPULATION STRUCTURE OF AVICENNIA MARINA (FORSSK.) VIERH. IN PUPIAN, KINMEN

林佳芸(Lin Chia-Yun) ； 曾彥學(Tseng Yen-Hsueh) ； 曾喜育(Tzeng Hsy-Yu) ； 王偉(Wang Wei) ； 呂金誠(Lu King-Cherng)

《中華林學季刊》 49卷3期 (2016/09) Pp. 211-228

摘要

本研究於2008年4月至2009年3月針對金門浦邊地區海茄苳進行族群結構調查，結果顯示海茄苳種子苗1年約可生長8.1節，植株高度增加約22 cm。海茄苳種子苗第1年生長量可以對應到稚樹植株節間數與植株高度關係的第1轉折點；第2個轉折點16個節間數，植株高約44 cm的植株可視為2年生苗木。調查發現，海茄苳樹齡不到1年半就可開花、結實，顯示海茄苳屬幼苗早熟種類。海茄苳具有顯著的生長季節性，其中以2008年7-10月的節間數與植株高度增加量最大的時期。地徑1-2 cm的海茄苳植株高度約80 cm，樹齡低於10年，當地徑超過5 cm時，植株達到最大高度約110 cm；地徑7.55 cm時，海茄苳樹齡約30年。將地徑5 cm帶入回歸式，顯示植株高度如達110 cm，通常已生長達20年。本研究調查2004-2008年5個繁殖體散播至幼熟木階段的同齡群，多數死亡率最高時期為10月到翌年1月，敏感度亦呈現相同變化趨勢。透過靜態生命表可發現金門浦邊地區海茄苳區分成8個生長階段，死亡率以G-H壯齡至老齡木階段最高，次高的死亡率為C-D幼熟木階段。海茄苳存活曲線屬於Deevey-Ⅲ型，存活率隨生長階段逐漸增加而下降，在繁殖體散播與幼熟木階段為存活率急遽下降的時期。未來應針對金門紅樹林族群數量進行長期的監測，提供管理單位在全球氣候變遷、海平面上升對金門地區紅樹林生長與繁殖的影響評估之經營管理依據。

關鍵字

海茄苳 ； 同齡群 ； 生命表 ； 族群結構 ； 存活曲線

並列摘要

The population structure of Avicennia marina (gray mangrove) in Pupian, Kinmen (Taiwan) was surveyed from April 2008 to March 2009. The results showed that the seedlings grew approximately 8.1 nodes per year, corresponding to an increase of approximately 22 cm in plant height growth. The year-growth of seedlings matched the first turning point in the relationship between the nodes and tree height. The second turning point in the node-tree height relationship was 16 nodes and approximately 44 cm in tree height, which would be considered a 2-year-old seedling. A. marina is a precocious tree that can bloom at the seedling stage (i.e., within the first 2 years of growth). The trees exhibited notable seasonal growth, with increases in plant height and the number of nodes reaching their highest rate during July-October 2008. The base diameter and tree height respectively reached 1-2 cm and approximately 80 cm by 10 years. By 30 years, the tree base diameters reached 7.55 cm. By the age of 20 years, a tree base diameter exceeding 5 cm generally indicated that the maximum tree height had been reached (approximately 110 cm). Static life table results revealed the growth stage of gray mangrove could be divided into eight growth stages, that the highest mortality rate occurred at the G-H stage, and the second highest mortality rate appeared at the C-D stage of young trees. The highest mortality rates of the five cohorts of 2004-2008 in these two life stages occurred between October 2008 and January 2009, and a similar trend in sensitivity was observed among all cohorts. In the Deevey type III survival curve, the survival rate decreased when the growth phase increased, and the health of young trees declined sharply at the stage of propagule dispersal. Further long-term monitoring of Kinmen gray mangroves should be conducted to facilitate impact assessments and ecological management under the conditions of global climate change and rising sea levels.

並列關鍵字

Avicennia marina ； Cohort ； Life table ； Population structure ； Survival curve