臺北縣三芝鄉淺水灣西側海岸沙丘地形與植群分布關係之研究

A Study on the Relationship between the Geomorphology and Vegetation Distribution of the Coastal Dunes in the Western Chianshuiwan, Sanjhih of Taipei County

陳彥樺(Yen-Hua Chen) ； 李建堂(Cheing-Tung Lee)

《地理學報》 51期 (2008/03) Pp. 1-20

https://doi.org/10.6161/jgs.2008.51.01

摘要

海岸沙丘為動態變化相當快的的風成地形，受到風力作用、海水作用、地形演育、植群分布等環境因子交互作用的影響，而呈現出複雜的生態系統。本研究藉由兩次實地的地形量測產出淺水灣西側沙丘的數值高程模型，瞭解研究區沙粒侵蝕及堆積的變遷情形，同時利用植物樣區法調查研究區內的植物分布狀況，在調查的193個樣區植物資料則利用雙向列表比較法（TWINSPAN）進行植群分類，藉以分析沙丘地形與植群分布之間的關係。研究結果顯示，沙丘的侵蝕、堆積變遷情形主要受植物覆蓋、海岸線走向、沙灘寬度、沙丘地形等影響，而高程、與海距離及地形特徵為影響植群型分布的主要因子。在低凹的地形環境，包括風蝕窪地及低地，因為地表較接近地下水面，環境較潮濕且背風有遮蔽，以灌木型的植物為主；在最前端近海的地形，包括圓頂丘、侵蝕坡、沙灘等，因為受風、波浪、鹽霧的擾動較大，沙粒移動性較高，以先驅性草本植物為優勢；在北側的沙丘斜坡地形，由於坡度較陡且迎風，攀緣藤本較能適應地形較陡峭且迎風的斜坡脊部。整體而言，海岸沙丘植群在不同地形因子影響下，植群結構、組成、功能、多樣性等產生些許差異，且在不同地形環境中亦可發現有不盡相同的優勢族群。

關鍵字

海岸沙丘 ； 數值高程模型 ； 植物地形學 ； 雙向列表比較法

並列摘要

Coastal dunes are dynamic landforms which feature complex ecosystem as a result of the interaction among wind process, marine process, geomorphologic evolution and vegetation distribution. Geomorphologic field surveys were conducted twice in the Coastal Dunes on the west side of Chianshuiwan to produce digital elevation models (DEMs), which were then used to investigate the short-term geomorphologic changes within the study area. Meanwhile, vegetation distribution data was attained from surveys of 193 quadrats. After classifying the vegetation with two-way indicator species analysis (TWINSPAN), the relationship between the dune geomorphology and vegetation distribution was analyzed. The result shows that the erosion and deposition changes of the dunes are due to factors including plant cover, shoreline alignment, beach width, and dune geomorphology. Elevation and the distance from the quadrat to shoreline are factors which affect the differences of the microenvironment within the vegetation zones. Areas like the blowouts and slacks that are wetter and more sheltered can supply shrubs with more water and nutrients. Whereas in frontal areas like hummocks, wave erosion scarps, and beaches, pioneer herbs are dominant because they can adapt to frequent disturbances and high sand movement. As for the northern slopes, the steepest region in the study area, vines with flexile stems usually climbed upward on the steep and windward slopes. Other differences of vegetation distribution were also found. As a conclusion, the geomorphologic characteristics led to some differences in coastal dune vegetation construction, composition, functions and species diversity. Therefore, different dominant communities could be found in various landforms.

並列關鍵字

coastal dunes ； digital elevation model ； DEM ； phytogeomorphology ； two-way indicator species analysis ； TWINPAN

參考文獻

三芝鄉公所(1994)。三芝鄉志。臺北:三芝鄉公所。

石再添、張瑞津、林雪美、張政亮、連偵欽(1992)。臺灣北部海岸沙丘之研究。國立臺灣師範大學地理研究報告。17，147-167。

石再添、張瑞津、林雪美、張政亮、連偵欽(1993)。臺灣西部海岸沙丘之地形學研究。國立臺灣師範大學地理研究報告。19，104-139。

石再添、張瑞津、林雪美、張政亮、連偵欽(1994)。臺灣南端與東部海岸沙丘之地形學研究。國立臺灣師範大學地理研究報告。21，2-34。

甘偉航(1988)。海岸竹枝籬堆砂功效評估及植物是砂功能調查。林業試驗所研究報告季刊。3，225-240。