玉山國家公園高山草原鳥類之海拔分布及族群密度變化
Other Title
Altitudinal Distribution and Population Densities of Alpine Grassland Birds in Yushan National Park
Journal
國家公園學報
Journal Volume
24
Journal Issue
1
Start Page
29
End Page
39
ISSN
1015-8413
Date Issued
2014-06
Author(s)
Abstract
臺灣的高山草原鳥類分布於中高海拔山區，在近年臺灣高山草原面積可能縮減的趨勢下，面臨棲地減少及氣候變遷的雙重衝擊。本研究調查六種高山草原鳥類在玉山國家公園東埔玉山區之族群密度、海拔分布及棲地偏好，進而探討其族群可能趨勢。我們在 2012 年於玉山國家公園內海拔 2500-3630 m 的高山草原內設置 60 個調查站，以定點計數法估算六種高山草原鳥類在繁殖季及非繁殖季時的族群密度，並測量各站之地被層平均高度及木本植物覆蓋度。這六種鳥類包括栗背林鴝 (Tarsiger johnstoniae) 、 臺 灣 叢 樹 鶯 (Bradypterus alishanensis) 、 臺 灣 朱 雀(Carpodacus formosanus)、黃羽鸚嘴(Paradoxornis verreauxi morrisonianus)、鷦鷯(Troglodytes troglodytes taivanus)、及深山鶯(Cettia acanthizoides concolor)。結果顯示，臺灣叢樹鶯、深山鶯、栗背林鴝、黃羽鸚嘴在 2012 年繁殖季的海拔分布上限高於之前在同區域所調查之結果。除黃羽鸚嘴外，其餘五種鳥類在繁殖季之族群密度高於及非繁殖季，顯示這些鳥種可能具有季節遷移現象，部分個體於非繁殖季降遷至海拔較低處活動。鷦鷯及栗背林鴝於繁殖季的族群密度與海拔之間呈顯著正相關，顯示這二種高山草原鳥類選擇高海拔處繁殖，承受較高的氣候暖化衝擊風險。
棲地偏好方面，深山鶯與黃羽鸚嘴的密度與地被層平均高度呈顯著正相關，深山鶯及臺灣朱雀的族群密度與木本植物覆蓋度呈顯著正相關，顯示這四種高山草原鳥類偏好較濃密的灌叢，或是可以適應木本植物覆蓋度較高的環境。未來若高山草原大幅演替為樹林應不會威脅這四種高山草原鳥類的族群存續，但仍需持續監測高山草原的變動與高山草原鳥類族群之間的交互作。
Alpine grassland birds distribute in mid- and high-elevation mountain areas in Taiwan. Due to shrinking area of alpine grasslands, these birds are under duel threats of global warming and habitat loss. We investigated the population density, altitudinal distribution and habitat preference of six alpine grassland bird species and explored their future population trends. We established 60 stations in the alpine grasslands of Yushan National Park and estimated the population density of Tarsiger johnstoniae, Bradypterus alishanensis, Carpodacus formosanus, Paradoxornis verreauxi morrisonianus, Troglodytes troglodytes taivanus, and Cettia acanthizoides concolor in the breeding and non-breeding seasons of 2012 by point counts. Results showed that upper limit of altitudinal distribution of B. alishanensis, C. a. concolor, T. johnstoniae, and P. v. morrisonianus in the 2012 breeding season was greater than previous investigations conducted in the same region. Population density of these six bird species in the breeding season was greater than that in the non-breeding season, indicating that part of these birds migrated to lower areas for wintering. The population density of T. t. taivanus, and T. johnstoniae was significantly and positively correlated with altitude, indicating that these two species prefer higher elevations for breeding and are under greater impact of climatic warming. Population density of C. a. concolor and P. v. morrisonianus was significantly and positively correlated with height of understory layer of vegetation, and population density of C. a. concolor and C. formosanus was significantly and positively correlated with coverage of woody plants. These results indicate that these bird species prefer habitats with dense shrub and more trees. If alpine grasslands are greatly converted into woodlands, habitat loss shall not greatly endanger these four alpine grassland species.
Subjects
高山草原
海拔分布
海拔遷移
氣候暖化
棲地選擇
植群演替
Alpine grassland
elevational distribution
elevational migration
global warming
habitat selection
vegetation succession
Publisher
內政部國家公園署
Type
journal article