蓮華池常綠闊葉林三種山龍眼屬植物之空間分布模式主要受棲位分化影響

Niche Partitioning Affects Spatial Distribution Patterns of three Helicia Species of the Lienhuachih Evergreen Broadleaf Forest, Central Taiwan

張勵婉(Chang Li-Wan) ； 邱少婷(Chiu Shau-Ting) ； 郭耀綸(Kuo Yau-Lun) ； 謝長富(Hsieh Chang-Fu) ； 李沛軒(Lee Pei-Hsuan)

《台灣林業科學》 34卷4期 (2019/12) Pp. 291-303

https://doi.org/10.7075/TJFS.201912_34(4).0005

摘要

同域同屬物種的共存是導致熱帶森林中α多樣性高的原因之一，因此瞭解棲位分化機制或傳播限制機制如何影響同屬植物同域共存，更可解釋熱帶森林中物種的高多樣性。本研究在台灣中部蓮華池森林動態樣區中，選擇山龍眼屬（Helicia）三種植物：蓮華池山龍眼（Helicia rengetiensis）、山龍眼（Helicia formosana）及紅葉樹（Helicia cochinchinensis），經由各族群的每木調查，記錄此三種植物的空間分布位置，並測量三物種之葉功能性狀、地形與土壤等環境因子，利用雙變數點格局分析，檢測山龍眼屬三種兩兩的空間分布的關係；利用鄰近矩陣主座標分析（PCNM）及方差分解，瞭解棲位分化機制或傳播限制對於其在森林中空間分布的影響。此外，也檢測三種植物加權平均之葉功能性狀與環境因子的關係。結果顯示此三種山龍眼屬植物兩兩之間皆呈現互斥現象；表示三種植物對於棲地皆有不同的需求；鄰近矩陣主座標分析及方差分解結果，顯示棲位分化是影響山龍眼屬在森林中分布的主要原因，可解釋力達60.6%。而地形及土壤等環境因子，亦影響三種山龍眼屬植物之葉功能性狀。整體而言，我們認為棲地分化是主要影響山龍眼屬植物空間分布的主要因素，同時影響著物種的葉功能性狀，維持同域同屬植物在森林中的共存與物種的多樣性。

關鍵字

山龍眼屬 ； 棲位分化 ； 空間分布 ； 蓮華池常綠闊葉林

並列摘要

Sympatric congeneric coexistence of species is a remarkable feature which causes high alpha diversity in tropical forests. Understanding how niche partitioning and dispersal limitations affect sympatric congeneric coexistence of species would help us explain the high species diversity of forests. In this study, environmental factors, leaf functional traits, and spatial distributions of 3 congeneric subcanopy tree species, Helicia formosana, H. rengetiensis, and H. cochinchinensis, were surveyed in order to understand the coexistence of these 3 species in the subtropical Lienhuachih forest dynamics plot in Taiwan. A bivariate point pattern analysis was used to test the relationship among the 3 Helicia species. Principal coordinates of neighbor matrices (PCNMs) and variation partitioning were used to study niche partitioning and dispersal limitations that affect the distributions of the 3 species. In addition, we also calculated community-weighted means of leaf functional traits to test trait-environment relationships. Results of the bivariate point pattern analysis showed repulsion between each 2 pairs of the 3 species. The PCNM and variation partitioning results explained 60.6% of the variations in niche partitioning. Our results also supported habitat divergence affecting the distributions of these 3 Helicia species and which was also reflected in the divergence of leaf functional traits. Overall, our results concluded that niche partitioning is the main process affecting the distributions of the 3 Helicia species. Meanwhile, it also affects the leaf functional traits of the 3 Helicia species and maintains the coexistence and species diversity of congeneric coexistence of species in the Lienhuachih forest.

並列關鍵字

niche partitioning ； Lienhuachih evergreen forest ； Helicia ； spatial distribution