- 期刊
- OpenAccess
Study of the Structure and Competitive Coexistence of Subalpine Krummholz Species in Taiwan
臺灣亞高山矮盤灌叢植群結構和競爭共存研究
摘要
Structural and spatial patterns of vegetation are essential to understanding the coexistence and competition among species in a community. In Taiwan, subalpine krummholz vegetation comprises 2 dominant species, Juniperus morrisonicola and Rhododendron pseudochrysanthum. We wanted to determine how these 2 species coexisted within a community on a high mountain in Taiwan. In total, characteristics of 403 individuals of these 2 species were examined at the Xue Mountain Glacial Cirque no. 1. Ripley's K function and a competition index were used to assess the coexistence relationship with intraspecific and interspecific competition between these 2 species. The spatial pattern revealed that trees at distances of 0-2 m had a random pattern, those at distances of 2-3 and 5-13 m had an aggregated pattern, and those at distances of > 13 m also had a random pattern. The sample species' competition index and traits were negatively correlated, indicating that the species with a greater diameter at the base were taller or had larger canopy and may thus have faced less competitive pressure. J. morrisonicola had a competitive advantage over R. pseudochrysanthum. These 2 species had different life strategies and supported each other through a mosaic distribution and a vertical canopy structure. Thus, they could coexist in a low-temperature, strong-wind, sunlight-intense, resource-deficient subalpine environment.
並列摘要
植群的空間結構和型態對於理解植物社會中物種之間共存和競爭關係至關重要。地處亞熱帶臺灣雪山一號圈谷的亞高山矮盤灌叢植群主要包含兩個優勢植物：玉山圓柏（Juniperus morrisonicola）及玉山杜鵑（Rhododendron pseudochrysanthum）。本研究主要探討為什麼這兩種植物可以在臺灣高山上的植物社會中共存？總計調查403株玉山圓柏及玉山杜鵑個體性狀特徵；並使用Ripley's K函數及競爭指數（CI）分析這兩個物種之間的種內競爭及種間競爭程度。根據Ripley's K水平空間分布顯示，在距離0－2 m處個體呈現隨機分佈，在2－3 m和在5－13 m處個體呈現聚集分佈，然而在距離大於13 m處個體之間也呈現隨機分佈。樣木的競爭指數與植物性狀特徵呈現負相關，表示地徑較大及樹冠幅面積較大的個體，受到較少的競爭壓力。玉山圓柏及玉山杜鵑具有不同的生活策略，且玉山圓柏比玉山杜鵑較具有競爭優勢，因此透過兩兩鑲嵌的分佈及樹冠層結構的相互支持下，能在低溫、強風、強日照且資源匱乏的高山環境中共同生存。