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108年度墾丁國家公園入侵黃狂蟻防治監測成效評估計畫

一、計畫緣起
在「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」、「106年度港口地區黃狂蟻調查」及「107年度墾丁國家公園黃狂蟻監測與防治計畫」的調查結果發現被國際保育聯盟 (IUCN) 列為世界百大入侵種的黃狂蟻 (Anoplolepis gracilipes)，已經在墾丁國家公園園區內主要的陸蟹分布熱區 (香蕉灣、砂島、湧泉區及港口) 有較高族群數量的分布，且在這兩年度的族群密度調查結果顯示，黃狂蟻已經在墾丁國家公園在部分陸蟹分布熱區中有形成的超級群落 (supercolony) 的現象，而造成墾丁陸蟹族群非常大的威脅。
二、方法及過程
108年度也將持續對於墾丁國家公園園區內陸蟹分布熱區中黃狂蟻分布族群密度較高的區域，進行液態餌劑與人工蟻巢誘引盒防治的防治作業，並持續評估兩種黃狂蟻的防治措施對於墾丁國家公園園區內的黃狂蟻防治成效，及評估黃狂蟻防治方法所潛在對於環境衝擊。將依據106-108年所進行三個年度黃狂蟻防治監測結果提出具體成效評估及後續管理建議，並建立園區陸蟹熱點區域中黃狂蟻監測及防治標準作業流程。目前計畫已完成後灣、香蕉灣、砂島、兩個湧泉區、港口等六個黃狂蟻監測調查樣區6次黃狂蟻監測調查 (2月、4月、6
月、8月、10月、12月) 與6次黃狂蟻防治作業 (1月、3月、5月、7月、9月、11月)。並於香蕉灣、砂島、湧泉區及港口等樣區中設置共60個人工蟻巢誘引盒設施，並於每月進行回收進駐的蟻巢。
三、重要發現
目前至108年12月的研究成果顯示港口仍是有較高密度的黃狂蟻的分布，各調查月份均有25%以上的採樣點調查到黃狂蟻，其次是香蕉灣、湧泉及砂島，後灣的黃狂蟻數量仍最少。本年度進行主要黃狂蟻防治 (餌站防治與蟻巢誘引盒) 的後灣、香蕉灣、砂島、湧泉區及港口區黃狂蟻的分布與密度都與去年明顯降低的趨勢。在不同樣區蟻巢間個體攻擊行為試驗的結果顯示，墾丁國家公園園區內的黃狂蟻族群已有形成超級群落的現象，在砂島與湧泉區的範圍間的蟻巢應屬於同一超級群落。
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，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，因此建議須持續對墾丁地區黃狂蟻的進行防治作業。
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
Based on the survey findings of [Invasion status of Anoplolepis gracilipes at Kenting National Park in 2017 & research and development of treatment strategies], [Invasion status of Anoplolepis gracilipes at Gangkou area in 2017], [Invasion status of Anoplolepis gracilipes at Gangkou area in 2018], A. gracilipes (considered by the IUCN to be among the 100 worst invasive species in the world) has been present at land crab hotspots (Hsiangchiaowan, Shadao, Natural Spring and Gangkou) and form high-density populations, and the formation of supercolonies poses serious threat to the endemic land crab populations.
2. Research methods
This year, we have continued to investigate the distribution and density of A. gracilipes populations at land crab hotspots in Kenting National Park, and further understand the actual distribution of supercolonies and its seasonal variation. This year, treatment with liquid bait have be carried out as well in areas with high-density A. gracilipes populations. The effectiveness of liquid bait have be evaluated, and we also assess the potential environmental impacts of this treatment method. In the first half of this project, monitoring survey of A. gracilipes populations have been completed in 6 study sites (i.e., Houwan, Hsiangchiaowan, Shadao, two Natural Spring, and Gangkou), included six times of monitoring survey (February, April, June, August, October and December) and six times of treatment operation (January, March, May, July, September and November), respectively. Furthermore, a total of 60 artificial nest was deployed around several study sites (i.e., Houwan, Hsiangchiaowan, Shadao, Natural Spring and Gangkou). These artificial nest were inspected monthly and those successfully colonized by A. gracilipes have be collected back to the laboratory.
3. Important findings
According to 12 months of survey effort, results have indicated that Gangkou area still have higher density and wider distribution of A. gracilipes populations, where more than 25% of sample points were found with this ants in each survey month, followed by Hsiangchiaowan, Natural Spring and Shadao areas. The number of A. gracilipes workers in Houwan area was still the least. The distribution and density of A. gracilipes populations in those area (Houwan, Hsiangchiaowan, Shadao, Natural Spring and Gangkou) controlled by liquid bait and removal of artificial nest were significantly lower than last year. Based on the results of intraspecific aggression assay between nests from different study sites, there was a possible sign of supercolonies formation in Kenting National Park, where different nests in both Shadao and Natural Spring areas likely belong to the same supercolony.
4. Main suggestion
i) It is crucial to 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 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：108

計畫主持人：林宗岐

中文關鍵字：長腳捷蟻、黃狂蟻、陸蟹、外來種、超級群落

英文關鍵字：Anoplolepis gracilipes, yellow crazy ant, land crab, invasive ant, supercolony.