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106年度墾丁國家公園黃狂蟻入侵狀況調查與防治策略研擬

一、研究緣起
墾丁國家公園近年發現有黃狂蟻 (Anoplolepis gracilipes Smith, 1857) 已進入園區並出現於陸蟹棲地，有鑑外來種黃狂蟻在印度洋聖誕島等地造成嚴重的生態危害，威脅到當地本土保育類陸蟹的生存。因此有其必要針對黃狂蟻在園區的入侵情況作全面性瞭解，首要針對園區陸蟹熱點，瞭解其入侵現況及對當地原生物種及生態所造成之影響，以作後續因應管理。
二、研究方法
於後灣海岸林、香蕉灣、砂島、湧泉區等四個陸蟹熱點區域 (圖四) 分別建立60、61、61、60及60個黃狂蟻監測調查樣點，以螞蟻餌站台放置在四個黃狂蟻監測調查樣區，黃狂蟻密度級數評估，以液態餌站在設置30分鐘左右誘引黃狂蟻數量為監測標準，是以30分鐘檢查餌站上黃狂蟻的數量(以照片輔助計算螞蟻個體數量)。密度級數將分為5個分級。於106年2月至12月完成了6次樣區調查。
三、重要發現
共記錄有22種螞蟻種類，螞蟻種類數以湧泉區種類最多，發現有19種螞蟻，其次是砂島的13種及香蕉灣的11種與後灣的11種。黃狂蟻分布上以湧泉區與砂島的分布最為廣泛，各調查月份均有20%以上的採樣點調查到黃狂蟻，其中又以湧泉區在10月份調查到50個樣點 (41.7%) 有黃狂蟻出現。砂島地區則是黃狂蟻的分布較廣與密度第二嚴重的區域，6月份的21個採樣點 (34.4%)最高，最低為2月有14個採樣點 (23.0%)，許多調查樣點屬於中高度或高度密度程度。以目前所調查結果呈現，人為干擾較為頻繁的地區 (漁港、農舍、農地等) 也是黃狂蟻分布與密度較高的區域，未來應就此人為干擾現象做進一步的分析討論。另外黃狂蟻取食偏好測試中發現，黃狂蟻對10% (w/v)蔗糖水與10% (w/v)蜂蜜水有高於其他配方的誘引力。建議使用3%硼砂混合10% 糖水誘餌進行防治黃狂蟻，於香蕉灣樣區已進行防治初期試驗。
四、主要建議事項
1. 應該持續監測與調查陸蟹主要熱點區域中黃狂蟻的分布與數量密度狀況，適度可增加調查區域的數量與範圍 (如佳樂水港口地區)，以確實了解此外來入侵螞蟻黃狂蟻的潛在族群狀況。
2. 目前調查除後灣外，其他陸蟹主要熱點區域都有一定程度黃狂蟻的分布與較高密度等級，尤其是湧泉區與砂島地區是目前黃狂蟻的分布最廣與密度最嚴重的區域黃狂蟻已有形成超級群落的現象，因此建議須立即進行墾丁地區黃狂蟻的防治作業。
3. 除進行一定程度的防治作業外，目前所調查結果顯示黃狂蟻的分布與一定程度的人為干擾有關，所以保護區中人為干擾現象的降低也是對黃狂蟻防治策略重要的關鍵。

計畫類別：[動物生態]

英文摘要：1. Research background
In recent years, yellow crazy ants (Anoplolepis gracilipes Smith, 1857) have been spotted inside Kenting National Park and also been found in the habitat of land crabs. Since this invasive ants have caused serious ecological damage on Christmas Island in Indian Ocean and elsewhere, and threatening the survival of endemic land crabs, there is a serious need to comprehensively understand the invasion of yellow crazy ants in the park. We primarily focused on land crabs hotspots, understanding the current status of yellow crazy ants and its impact on the endemic species and ecology, for follow-up management of this ants.
2. Research methods
Field survey was carried out at four land crabs hotspots: Houwan, Hsiangchiaowan, Shadao, and Natural Spring areas (Figure 4) where total of 60, 61, 61, and 120 sample points were set up, respectively. Liquid bait stations were deployed at the four study sites, and the yellow crazy ant density score was assessed based on the number of foraging ants above the bait station after 30 minutes of deployment (digital images of ant individuals were captured to assist calculation). The density score was divided into 5 categories. From February to December 2017, a total of 6 samplings were completed.
3. Important findings
A total of 22 ant species were recorded in this study. Highest ant-species richness was found in Natural Spring, with 19 ant species discovered, followed by 13 ant species in Shadao, 11 ant species in Hsiangchiaowan and Houwan, respectively. The distribution of yellow crazy ants is most widespread in Natural Spring and Shadao areas, where more than 20% of sample points were found with this ants in each survey month. In Natural Spring, total of 50 sample points (41.7%) were found with yellow crazy ants in October. Among 4 study sites, Shadao has the second widest distribution and second highest density of yellow crazy ants, with widest distribution in June (21 sample points, 34.4%) and least distribution in February (14 sample points, 23.0%). Many sample points categorized as medium-high or high density. According to current results, human-frequented areas (fishing port, farmhouse, agricultural land, etc.) have the highest distribution and density of yellow crazy ants, further research on this anthropogenic influence should be conducted in the future. In addition, yellow crazy ants highly attracted to 10% (w/v) sucrose and 10% (w/v) honey solution compared with other bait formulation in bait preference test. Recommended to mix 3% borax with 10% sucrose solution as bait attractant in the control of yellow crazy ants, and preliminary control experiments will be conducted in Hsiangchiaowan area.
4. Main suggestion
i) We should continue to monitor the distribution and density of yellow crazy ants in the main land crabs hotspots as well as moderately expand the number and range of survey areas (e.g. port area in Jialeshui) to truly understand the invasion of this ant species.
ii) Apart from Houwan area, all other land crabs hotpots have certain degree of distribution and density of yellow crazy ants, where both Natural Spring and Shadao areas have the widest distribution and highest density of this invasive ants with signs of supercolonies formation. Hence, it is recommended to carry out the management and treatment of yellow crazy ants immediately.
iii) Other than chemical treatment, the current results have shown that the distribution of yellow crazy ants related to human disturbance to a certain degree. Therefore, the reduction of human disturbance inside the park also play a crucial role in the management of yellow crazy ants.

辦理單位：國立彰化師範大學

計畫屬性：本處委託辦理

執行年度：106

計畫主持人：林宗岐

中文關鍵字：黃狂蟻、陸蟹、外來種、墾丁國家公園、液態餌劑

英文關鍵字：Yellow crazy ant, Land crab, Exotic species, Kenting National Park, Liquid bait