澎湖縣青螺濕地紅樹林生長及族群結構之研究

The Growth and Population Structure of Mangrove at Chinglo Wetland, Penghu County, Taiwan

陳正倫(Cheng-Lun Chen)

指導教授 ： 范貴珠

國立屏東科技大學/農學院/森林系所/碩士(2012年)

https://doi.org/10.6346/NPUST.2012.00274

摘要

本研究以澎湖青螺真武廟前濕地之紅樹林復育區為主要調查地點，於2011年3至11月間進行濕地環境、復育栽植4種紅樹林生長及族群結構等調查。調查結果顯示不同季節調查之水質pH、電導度、鹽度、溫度濁度等參數差異不大，均屬於紅樹林生長之適合範圍內，而水質之總氮及總磷濃度均低(<0.05 mg/L)。土壤調查結果顯示濕地不同樣區之底質機碳含量均小於3%，氮含量亦小於0.1%，範圍為433-310 mg/kg，均為不足狀態，但磷含量則介於941-2170 mg/kg之間，屬於足夠狀態。土壤粒徑分析結果顯示本濕地砂粒均在50%以上，表示本濕地為一通氣性佳，但保水及保肥力較差的環境；此外，各調查樣區較易漂移的極細砂粒較少，此可作為濕地復育紅樹林成效良好之指標。
本復育區於1994至2000年間，在濕地中5個不同區域直播或直插海茄苳(Avicennia marina)、五梨跤(Rhizophora stylosa)及水筆仔(Kandelia candel)繁殖體，而欖李(Lumnitzera racemosa)則栽植1年生之容器苗，本研究調查復育栽植紅樹林至今之生長狀況，結果顯示經過18年時間後，4種紅樹林之生長已明顯呈現差異；其中以直播方式復育耐鹽性強之海茄苳已成為優勢種，但生長相當緩慢，平均樹高範圍僅在0.6-1.4 m間，地徑範圍為2.51-7.47 cm。栽植在濕地靠岸邊之欖李目前雖然成活，但整體之生長勢已逐漸老化衰退，而水筆仔及五梨跤之生長則呈現停滯狀態，平均樹高分別僅有1.0及1.3 m。此外，濕地內海茄苳天然更新苗數量多，以致海茄苳面積逐漸往周圍擴展，惟周圍受魚塭堤岸限制，因此未來族群拓展面積將受限。本研究以永久樣區推算海茄苳和全區調查之五梨跤族群結構呈反J型，表示天然更新情況良好。調查全區水筆仔及所呈現之族群結構則呈現鐘形，顯示天然更新狀況不佳。

關鍵字

澎湖 ； 青螺濕地 ； 生長 ； 族群結構

並列摘要

This study set its major monitoring site for mangrove restoration at Chinglo wetland of Penghu County, where several observations had been conducted from March 2011 to November 2011. The study monitored wetland’s environment, growth of mangroves, population structure and status of mangrove expansion. The results on wetland’s environment showed that there was no significant variation between different seasons; the indices studied included water pH value, electrical conductivity, temperature turbidity. These indices were all within the normal growth condition for mangroves, but with lower total nitrogen and total phosphor levels (<0.05 mg/L). The soil in different sampling subplots revealed insufficient carbon and nitrogen level, which was less than 3% and 0.1% (310-433mg/kg), respectively. However, the phosphor level was in the sufficient range, between 941mg/kg to 2170mg/kg. Furthermore, the soil content analysis revealed high sand particle concentration with an average of more than 50%, indicating that the wetland’s environment has a good ventilation system but poor water and nutrient preservation capabilities. In addition, every sampling subplot exhibited low tiny sand granules. These granules were undesirable for its unstableness, thus, such finding could be used as a good indicator that the observed wetland was successful on mangrove restoration.
Previously, between 1994 to 2000, National Pingtung University of Science Technology and Penghu County government chose five different sites in the wetland for seeding and Avicennia marina, Rhizophora stylosa, Kandelia candel, and Lumnitzera racemosa were planted. They were directly sowed with propagules except for L. racemosa, which were planted with one-year-old seedlings. After 18 years, differences in developments were observed among the four mangroves. The directed sowed A. marina which exhibited high saline tolerability had become the dominant specie; however, its growth rate was considerably slow, with average of 0.6 to 1.4m in height and 2.51 to 7.47cm in growth radius. Even though L. racemosa grown near the wetland coast survived, the overall growth curve had declined. The growth of R. stylosa and K. obovatal appeared to be halted, with average height of 1.0m and 1.3m, respectively. There was high number of wildly grown A. marina, making the specie easy to expand in growth area. However, with the limitation imposed by neighboring fish farms, the specie was restricted for further expansion. The population structure analysis based on the permanent growth area of A. marinas and on all subplots of R. stylosa showed upside-down-J shaped roots, which were indications of good natural growths. The population structure analysis on K. obovatal showed bell curve which indicated a poor natural regenerating growth.

並列關鍵字

Penghu ； Chinglo wetland ； growth ； population structure

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