太魯閣地區鳥類群聚的時空變化

Temporal and Spatial Variations of Bird Assemblage in Taroko National Park

彭鈞毅(Chun-Yi Peng)

指導教授 ： 李培芬

國立臺灣大學/生命科學院/生態學與演化生物學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.03236

摘要

東部太魯閣地區特殊的峽谷地形及氣候形態，與西部地區南轅北轍，因而孕育出獨特的生物群聚形式。本研究欲探究太魯閣地區的鳥類群聚，著眼於太魯閣山區：（1）各鳥種的海拔分布；（2）各鳥種海拔分布的季節變異形式；（3）鳥類群聚的現況，以期了解與西部鳥類群聚的差異情形。
自2006年4月至2007年3月，於太魯閣國家公園沿完整海拔梯度設立樣點，以圓圈法進行一個月兩次，共24次的鳥類調查。依繁殖季與非繁殖季，將各樣站所調查到的鳥種，繪製了24種鳥種的海拔分布，並比較季節間的差異。此外，另描述物種豐富度與海拔梯度的關係，最後依照各鳥種在生態同功群的分類，檢視其分布與組成及季節間的變化。
共紀錄到31科99種鳥種，依各鳥種季節性海拔分布的差異，共歸納出7種主要的形式：相對於繁殖季，非繁殖季時（1）海拔分布的下限往下移、（2）海拔分布的上限往下移動、（3）海拔分布的上下限皆往下移動、（4）海拔分布的上下限擴張、（5）海拔分布的上限往上移動、（6）海拔分布上下限皆往上移動、（7）海拔分布上下限沒有太大差異。繁殖季與非繁殖季鳥類物種豐富度沿海拔梯度皆為駝型分布。同功群的分布與組成方面，繁殖季時，肉食者分布在低海拔（海拔高度0–1,500m），飛啄蟲食者分布涵蓋低、中海拔（海拔高度1,500–2,500m），樹幹蟲食者、地面蟲食者位於中海拔，樹層蟲食者分布於中、高海拔（海拔高度2,500m以上），地面雜食者分布在高海拔的區段，其他的同功群在各海拔區段皆有出現。非繁殖季時，各類型蟲食者的海拔分布往下移動，各類雜食者與肉食者的分布未改變，樹層植食者只有在非繁殖季才出現。各海拔的同功群組成亦不相同，繁殖季低海拔的優勢同功群為樹層雜食者、飛啄蟲食者，中海拔為樹層雜食者、樹層蟲食者，高海拔為灌層蟲食者和樹層蟲食者。季節間的比較中，非繁殖季樹層植食者取代了部份的樹層雜食者，成為優勢同功群；各類型蟲食者在原海拔同功群組成的比例減少，中、低海拔地區所佔的比例增加；高海拔地區地面雜食者取代灌層蟲食者成為優勢同功群。
本研究認為太魯閣與西部地區鳥類的分布和季節間海拔遷移跨幅的差異，來自於地形與氣候形態的影響。與過去研究不同的海拔遷移形式和歸納鳥種的差異，則來自調查方法和研究海拔範圍的不同。因此，釐清環境背景間的差異可以幫助了解影響鳥類群聚的重要因子；而沿連續海拔梯度的研究方法對於鳥類群聚的描述能更為清晰。

關鍵字

鳥類群聚 ； 同功群 ； 海拔梯度 ； 季節變異 ； 太魯閣

並列摘要

Topographic features and weather patterns in Taroko Gorge are different from the western slope of Central Mountains, resulting in special bird assemblage in Taroko. To investigate the differences between Taroko and the western slope of Central Mountains, I studied the bird assemblage in Taroko and focused on: (1) avian distribution along elevation gradient (2) patterns of seasonal distribution changes (3) distribution and composition of guilds.
Seventy-four sampling sites along Central Cross-Island Highway were inventoried twice a month from April 2006 to March 2007. I compared the distributions of 24 species of birds in breeding and non-breeding season. Moreover, I viewed the relationship between species richness and elevation gradient and studied the guild distribution and composition along elevation gradient.
I recorded 31 different genuses, totaling 99 species, and generalized seven patterns of seasonal distribution changes. After comparing it with the breeding season, the distribution pattern changes were: (1 ) lower limit moved downward. (2) upper limit moved downward. (3) both upper and lower limit moved downward. (4) both upper and lower limit expanded. (5) upper limit moveed upward. (6) both upper and lower limit moveed upward. (7) both upper and lower limit remained the same.
Species richness show a hump-shaped relationship along elevation gradient. With regards to the guild during breeding season, carnivore distribution is in the low altitude(0–1500m), bole insectivores and ground insectivores are found in mid altitude(1500–2500m), tree insectivores distribute in mid and high altitude(>2500m), ground omnivores distribute in high altitude, and other guilds distribute evenly across the altitudinal gradient. . In non-breeding season, all insectivores’ distributions move downward, omnivores and carnivores do not change their distribution, and tree herbivores only appear in this season. Composition of guild along elevation gradient in breeding season shows that in low altitude the dominant guild are tree omnivores and fly-catch insectivores, in mid altitude the dominant guilds are tree omnivores and tree insectivores, and in high altitude dominant guilds are shrub insectivores and tree insectivores. During the non-breeding season tree herbivores replace part of tree omnivores and become dominant guild, all species of insectivores decrease their weight in their original altitude and increase their weight in lower altitude, and in high altitude ground omnivores replace shrub insectivores and become dominant guild.
We concluded that the distributions and heights where the bird moves in between seasons in Taroko are different from the patterns on the western slope of Central Mountain and result from the difference of topography and weather patterns. Different movement patterns from the past research were due to resource distribution, different research methods, and different research boundaries. Understanding the background of study site helps us better understand the factors affecting bird distribution, and the full elevation gradient research can clearly describe the bird assemblage.

並列關鍵字

bird assemblage ； guild ； elevation gradient ； seasonal changes ； Taroko

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