磐石山區高地草原台灣水鹿之日間行為

Diurnal behavior of Formosan Sambar on Alpine Grassland at Pans Mountain

郭正彥(Jeng-Yan Guo)

指導教授 ： 王穎

國立臺灣師範大學/理學院/生物學系/碩士(2004年)

摘要

台灣水鹿為台灣野外現存體型最大的哺乳動物之一，然而野生水鹿的行為時間分配如何仍未有所悉。2003年4月至2004年12月間於台灣中北部的磐石山區觀察高地草原上的台灣水鹿（Cervus unicolor swinhoei）的行為，以檢測性別成幼、季節、日間時段、氣溫、棲地類型、社群數量和社群組成等生態因子對於水鹿每日目擊率和各項行為時間分配之影響。研究期間總共目擊459群（次）的水鹿，平均每群有1.32隻次的水鹿，而以單獨1隻的出現比例最高，且雄鹿較幼鹿和雌鹿傾向於單獨出現。夏、秋兩季每日目擊率（0.91±0.49、1.06±0.58隻次/時）顯著高於春、冬兩季（0.49±0.32、0.35±0.27隻次/時）。不同日間時段的每日目擊率以清晨時段（~0800）最高，其他時段較低。以每10秒鐘為時間間隔的瞬時記錄法記錄於高地草原活動之水鹿的行為，共獲得472筆最短時間為5分鐘之行為資料，總記錄時間為188.7小時。水鹿日間行為模式以覓食行為之時間分配（61.73%）最高，休息行為次之，位移、反芻和社會行為皆僅佔10%以下，其他行為所佔之時間分配最低。高地草原水鹿攝食的食物種類以玉山箭竹為主，共佔全部攝食次數的98.38％。雌鹿之覓食率顯著高於幼鹿和雄鹿，且其覓食率四季變化甚微；雌鹿之尋食率顯著高於幼鹿和雄鹿，但三者之間的攝食率並無顯著差異。雄鹿覓食率之季節變化以秋季顯著高於其餘三季，然而秋季亦為雄鹿繁殖活動的高峰，與溫帶鹿種於繁殖高峰時覓食率較低的狀況不同。雄鹿和雌鹿尋食率之季節變化呈現春季往冬季遞減的趨勢，幼鹿覓食率則無季節變化。比較坐臥前後5分鐘的水鹿覓食率，以坐臥前顯著高於坐臥後（P<0.001），為坐臥後水鹿自我修飾的時間分配較坐臥前增加所致（P<0.05）。水鹿之尋食率和選擇指數呈現高度正相關，以兩項指標其中之一即足以說明整體水鹿之覓食選擇。不同性別成幼水鹿的覓食警覺性中，三項警覺性指標皆有顯著差異，但唯有掃視時間間隔符合雄鹿警覺性最低的預測。此外，整體水鹿的偵測比例在森林邊緣顯著低於高地草原，鹿群數量和群內成員組成對鹿隻警覺性的影響皆不符合預期，在掃視頻率的分析中，與幼鹿集群的母鹿警覺性反而顯著低於未與幼鹿集群之雌鹿。水鹿臥姿反芻的平均長度顯著高於站姿反芻，但不同雌雄和時段之間並無差異。社會行為的時間分配以雄鹿顯著高於其餘兩者，雄鹿的社會行為多為非接觸性的標示行為，其中以磨角行為的出現比例最高。水鹿的自我修飾可分為三類，其中以嘴舔飾最常見（91.04%），以腳抓飾次之（8.53％），以角抵飾則僅在雄鹿觀察過3次。雄鹿的自我修飾率顯著低於雌鹿和幼鹿，應與其出現頻率較高的泥浴行為有關。每日排糞率為8.16至13.92（回/天），以成體略高於幼體水鹿，其中走動和站立排糞的比例分別為45％和55％。氣溫和水鹿甩耳率之間呈現顯著正相關。水鹿的避敵反應中最常見為豎尾行為（83.33%）和警戒叫（59.52%），前肢單腳踱地出現機率較低（26.19%），且常兩種以上同時出現。將所得六項行為分隔為活動（覓食、位移、社會和其他）和不活動（休息和反芻）進行晝間活動模式的分析，高地草原台灣水鹿的晝間平均相對活動量為72.75％，偏向於較活動狀態，且以10時和16時最高，6時、11時和17時最低，呈現顯著之多峰型活動模式。活動量之季節變化以冬季和夏季顯著低於其餘兩季，然而天氣陰晴對水鹿之活動量並無影響。

關鍵字

台灣水鹿 ； 覓食 ； 行為 ； 警覺性 ； 高地草原 ； 活動模式

並列摘要

Sambar deer (Cervus unicolor) are the largest deer in East-Southern Asia, but very little knowledge about their behavior is known, especially the quantified field data such as behavioral time budget. From April 2003 to December 2004, the behavior of wild Formosan sambar (C. u. swinhoei) was observed on an alpine grassland at Pans Mountain, Central-Northern Taiwan. A total of 459 deer groups were sighted in 796.4 hours and the mean group size of sambar were 1.32deer/group. Sighting rates were significantly higher in summer and fall (0.91±0.49, 1.06±0.58 group/hr) than in spring and winter (0.49±0.32, 0.35±0.27 group/hr), and were highest in early morning (before 8 a.m.) compared to other five daytime periods. Grouping pattern of alpine Sambar has a trend to be solitary or in pairs all the seasons, while male sambar were more solitary than females and fawns. Sambar spent most of their daytime on foraging (61.73%) and less time on resting, ruminating, locomotion and other behavior. Compared to other two age-sex classes, female sambar spent more time on foraging and searching. However, females spent similar time on feeding with males and fawns. For female and fawn, the seasonal changes of foraging rates were not significantly different, but were greater in fall coincided with the rutting season for males. Based on our annual observation, the searching rates of sambar declined from spring to winter for males and females, but not for fawns. Foraging rates of sambar before bedding were significantly greater than the ones after bedding (P<0.001), and were attributed to the higher self-grooming rates after bedding (P<0.05). In spite of age-sex classes, searching rates of sambar were positively correlated with another indicator of food selection, the select index. Therefore, both indicators were representative of food selection for alpine sambar in this study. All three vigilance indicators of sambar were significantly different from each other when considering three sex-age classes of sambar, but only one of them, the intra-scan interval, conformed to our prediction that males were less vigilant than females and fawns because of their large body size and their sex-age-related weapon (antler). Besides, time spent scanning of sambar when foraging on grassland were significantly greater than the those foraging on forest edge, and the result were agreed to our observation about their fleeing response to shelter, the forest. Other biological factors, however, such as group size and composition did not affect the vigilance of sambar, except for an unusual result that the scan rates of females with fawns were lower than those without fawns. Time spent on resting or ruminating of sambar was nearly fifty-fifty after sambar bedded. On the other hand, mean time period of ruminating bout of sambar while bedding were significantly greater than those while standing. Among three sex-age classes of sambar, males spent more time on social behavior, which had a high proportion of marking behavior, than female and fawn. In addition, rubbing with antler was the most common marking behavior for male. Among three distinct sort of self-grooming behaviors of sambar, oral-grooming occurred most often (91.04%), followed by scratch- grooming (8.53％) and antler-grooming (only three times for males). Moreover, males spent less time on self-grooming, which might be reduced by their wallowing behavior with a possible function of removing ectoparasites. Sambar excreted their droppings with a posture of standing (45％) or walking (55％), and the defecation rates for adults were slightly greater than for fawns with a range of 8.16 to 13.92 (bouts/day). The degrees of ear flicking were significantly correlated with ambient temperature in spite of standing or bedding. Anti-predator responses before fleeing caused by observer were classified into tail-flagging (83.33%), snorting (59.52%) and stamping ground with forelegs (26.19%), and more than two of them could occur spontaneously. We classified foraging, locomotion, social and other behaviors as “active” phase and resting and ruminating as “inactive” one of sambar. Therefore, the average relative diurnal activeness of sambar was 72.75%. On this alpine grassland, we believed sambar were more active than on other unstudied habitats. During daytime, the more active hours of sambar were at 10 a.m. and 16 p.m. while less active ones were at 6 a.m., 11 a.m., and 17 p.m. Furthermore, relative diurnal activeness was lower in winter and summer than other two seasons, but no differences were detected between sunny and cloudy days in our analysis.

並列關鍵字

Formosan sambar ； Cervus unicolor ； foraging ； behavior ； vigilance ； alpine grassland ； activity pattern