淺山生態系最美麗的

貓科動物——石虎
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2012 / 11月

文‧李珊 圖‧陳美汀提供


被列為一級保育類瀕危動物的石虎和雲豹,是台灣僅有的二種野生貓科動物。

生性機警、隱密的石虎是夜行性動物,體型類似家貓,在野外極不容易發現,調查難度高,多年來資料闕如。直到6、7年前學界投入研究後,牠的神秘面紗才逐漸揭開。

近年來在石虎族群量較高的苗栗縣,因開發計畫波及,石虎處境堪虞,需要各界關心,保護這個最靈敏的貓科動物。


「以前以為石虎在深山,傻傻地跑進深山調查,後來才知道稀有的寶貝在這。」10月初,屏東科技大學博士生陳美汀正在為苗栗通霄護林協會成員講授「低海拔野生動物生態」,希望這些向林務局承租國有林地的在地居民,能擔任保育石虎的尖兵。

體長55~65公分的石虎,尾巴長達30公分,體重3~6公斤,灰褐色或黃褐色、全身有豹狀斑點,又稱豹貓或山貓;石虎外形和一般民眾飼養的虎斑貓相似,但紋路不同(虎斑貓身體條狀紋,尾巴環狀紋),較明顯的差異是,石虎耳朵後面有白色斑紋。

陳美汀解釋,苗栗靠近聚落的淺山地區集合了闊葉林、人造林、竹林、農墾地、埤塘等各樣地景環境,孕育了23種哺乳類,其中包括石虎,以及穿山甲、麝香貓、食蟹等保育物種。

淺山寶地的孕育環境

令人好奇的是,為什麼靠近人類居住的環境,反而聚集不少野生動物?

原因是,聚落附近的草生地、農墾地、林地有許多鼠類、野兔可供石虎食用,森林中常在地面活動的鳥類(如竹雞),也是石虎的食物來源,森林庇蔭則提供石虎養育下一代的保護環境,造就了良好的生存空間。

通霄護林協會成員長年以種植相思、油桐等經濟樹種為業,是苗栗地區少數仍在積極運作的林農組織,近年在林業單位護林政策下,銷售木材收益越形單薄,亟思轉型,因而應林務局之邀加入「社區林業」計畫。

「這裡的租地多是石虎的棲地,居民是最佳的石虎調查員,」林務局新竹林區管理處技正余建勳表示,林務局計畫在苗栗劃設石虎保護區,需要有足夠的研究資料,協會對石虎保育已有共識,希望在第二代林農的參與下,達到社區發展和保育雙贏的目的。

這天下午,一行人拉拔到銅鑼和通霄交界的虎頭崁進行戶外實習課。從稜線鳥瞰通霄,幾個聚落散布在蓊鬱山丘間,稻田、果園景觀錯落,正像陳美汀形容的「鑲嵌地景」。

陳美汀帶領眾人離開產業道路進入新竹74、75號林班地探查,一路上看到獸徑痕跡便往林子裡鑽,不久後即找到一坨灰白色乾燥石虎排遺(大便)。

「看顏色已經有一段時間了,新鮮排遺是咖啡色,大小很像家貓,這些毛是刺鼠背後的鋼毛。」陳美汀說,石虎和家貓不同,從不把便便埋起來,反而會用它來標示活動領域;學員日後若自己發現石虎出沒的地點要記下座標、排遺數量,還得記得埋起來,以免別人重複紀錄。

對石虎來說,排遺除了有宣示活動領域的作用外,也是吸引母石虎的訊號。

陳美汀表示,石虎的活動範圍很大,公石虎可在廣達5~6平方公里(5~600公頃,相當於10個關渡自然公園)的區域趴趴走,母石虎則在1.5~1.8平方公里活動。傍晚到隔日清晨5點前是活動高峰期。

「要不是有陳美汀投入研究,石虎的處境更不堪設想,」余建勳說,近年苗栗縣幾宗開發案,例如苗50線、台13線的外環道開路計畫,如果沒有石虎的棲地資料作為環境評估的輔助,一旦開路成功,棲地破碎化,將使情況雪上加霜。又如後龍「福祿壽殯葬園區」的開發案,因當時環評並沒有對石虎棲地的衝擊進行評估,後來立法院、環保團體都呼籲重做,因此這件開發案仍有溝通協調的空間。

就像研究各種野生物種的專家,都有一段投入的故事,陳美汀研究石虎正因她愛貓成癡。

愛貓成癡

大學讀歷史系,畢業後到木柵動物園工作,擔任夜行館的動物照養員。2年來和美國大山貓、石虎等中小型貓科動物朝夕相處,雖然滿足了近距離觀察的渴望,但她發現,動物園和保育工作差很大。她轉而到美國讀書,碩士論文就以台灣貓科動物為研究主題,由於貓科中的台灣雲豹已絕跡,只好研究石虎。

當時屏科大指導教授裴家騏認為,國內石虎資料闕如,2年內要做出成果,並不容易,因此建議她將研究範圍擴大到「小型食肉目」動物,也就是除了石虎,同時調查食蟹、麝香貓、鼬獾等小型哺乳動物的分布和生態,就以高、屏為採集樣本區。

果然不出裴家騏所料,石虎蹤跡難以尋覓,陳美汀研究小型食肉目期間,還曾被虎頭蜂螫一百多針差點喪命。

「被虎頭蜂叮能存活的紀錄是五十幾針,」陳美汀說,被叮後她躲在溪水中,虎頭蜂才慢慢散去,但送醫後卻因沒有立即進行洗腎換血,延誤病情,轉院後一度發生腎衰竭,多重器官內出血,全身皮肉潰爛,在加護病房躺了二十幾天才撿回一命。

然而經此大難,仍不改她的研究熱情,取得碩士學位後,她從野生動物的救傷資料發現,苗栗、南投一帶有石虎蹤跡,對照南投特有生物中心的調查資料也都獲得佐證。

陳美汀的博士研究,就決定鎖定石虎,並以新竹、苗栗一帶的淺山為研究樣區。只是,從苗栗到嘉義的淺山地區雖有石虎出沒的紀錄,但深山裡究竟還有多少石虎?現有資料雖然顯示機率很低,但仍必須深入調查。

山中小霸王揭密

石虎行動敏捷、飄忽不定,要擴大範圍調查其出沒區域,需要藉助紅外線自動相機,2005年裴家騏向林務局申請經費,由陳美汀在苗栗137個樣點和新竹72個樣點架設相機,經過3年調查畫出了石虎的分布圖。

同時,陳美汀也在2007~2008年捕捉到6隻石虎,繫上無線電發報器做追蹤,藉以研究石虎的活動範圍和活動時間等生態習性。

「石虎真的很會跑,我們騎機車都追不到,」陳美汀以一隻追蹤了三百多天的「阿樹」為例,這隻又帥又壯的公石虎,一個晚上最遠可以跑2~3公里,每當她和同伴追蹤到訊號要停車定位時,阿樹又不見蹤影,他們只能迅速定位後,立刻向前追,一個晚上操下來,二個人都精疲力盡。

有一次,她一個人在颱風天做無線電追蹤,擔心風雨,又怕碰到壞人,一個晚上神經都是緊繃的。陳美汀回憶說,那天追蹤的「阿耿」一整晚都在跑來跑去,一度與牠相距不到10公尺,當時已近清晨又有大霧,她興奮中靜靜地等待,心想也許可以近距離看見,突然間阿耿又跑開了。

由於苗栗居民常目擊石虎,陳美汀也透過問卷訪查了解。例如曾有阿伯看到母石虎帶4隻小石虎;也有獵人說,石虎爬樹能力極佳,還聽到不少居民描述石虎捕捉雞隻,「抓了雞就往肩上一甩,大搖大擺的走了。」

陳美汀多年研究下來,對於石虎仍有很多未知的生態習性待了解,如繁殖季節、繁殖行為、育幼方式,台灣其他淺山地區的族群數和面臨問題等,都還需要深入研究。

棲地被破壞的生存危機

翻開全球圖譜,石虎的棲地主要在東亞和東南亞地區,是小型貓科動物中分布最廣、適應力最強的種類,可在熱帶雨林、針葉林、半沙漠等截然不同的環境存活。

而台灣是海島,較之大陸型地區,石虎的生存問題更為嚴峻。首先是棲地減少和破碎化,例如後龍殯葬園區的開發,雖然面積僅有幾十公頃,但在已殘存破碎的棲地開發,一定會造成石虎的食物大量減少。

其次,道路開發也有嚴重殺傷力,今年3月苗128線道同一地點相隔8天就有2隻石虎命喪車輪。

最後,人為的捕獵、捕獸夾和毒餌傷害,更是危機。以陳美汀無線電追蹤的6隻為例,後來有5隻都是遭獸夾夾死、毒餌毒死和捕捉而被迫中斷研究。活動力極強的「阿樹」被捕獸夾夾到2次,最後被毒死;另一隻年紀老邁的「阿嬤」,因為經常跑到養雞場捉雞,最後也被捕獸夾夾死。

陳美汀非常難過,但也只能更努力拜訪宣導,讓苗栗鄉親知道石虎是重要的保育物種,請大家手下留情。

好在,近年林務局和苗栗自然生態學會已積極加入保育行列。林務局到各鄉鎮小學介紹石虎;生態學會則與消防局合作,宣導救傷石虎的知識,也建立養雞場通報系統,為養雞場架設紅外線攝影機,提供協助調查獎勵金等。經過兩年宣導,民眾熱心通報受傷或在道路撞死石虎的件數,都有明顯增加。

保育人士更希望能推選石虎成為苗栗的幸運動物代言人,就像日本琉球列嶼西表島的「西表山貓」被選為觀光大使,島上馬路常見「注意山貓」標示,政府並為牠們開闢動物廊道,所有產品上都印上山貓標誌,觀光客無不津津樂道。

台灣最美麗的貓科動物,絕對能勝任苗栗觀光代言的工作,這不僅是旗艦物種石虎的轉機,也是淺山生態系中其他保育物種的福音。

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EN

Beauty on the Prowl—Taiwan’s Leopard Cats

Coral Lee /photos courtesy of courtesy of Chen Mei-ting /tr. by Scott Williams

The endangered leopard cat is one of only two wild cat species native to Taiwan.

A nocturnal predator with a build similar to that of a housecat, it is both clever and secretive. Hard to spot in the wild and difficult to study, the cats were for many years something of a mystery. That began to change six or seven years ago, when researchers finally began uncovering the cats’ secrets.

Miaoli County has a relatively large population of leopard cats, but development has endangered this cleverest of cats. We must work together if we are to save them from the threats they face.


“I used to think that leopard cats lived deep in the mountains, and just barged into those areas like an idiot to do surveys,” says Chen Mei-ting, a PhD candidate at National Pingtung University of Science and Technology (NPUST), in an early October lecture to Miaoli’s Tongxiao Forest Conservation Society on low-elevation wildlife and ecosystems. “Later, I learned that these precious animals live right among us.” Chen is giving her lecture today in hope that her audience, local residents who lease national forestland from the Forestry Bureau, will move to the forefront of efforts to conserve the leopard cat.

Leopard cats are speckled, ash-brown or yellow-brown in color, and weigh three to six kilograms. Their bodies are 55–65 centimeters long and their tails about 30 cm long. Truth be told, leopard cats don’t look all that different from a tabby housecat, the most obvious difference being the white patch they have behind their ears.

Chen says that Miaoli’s low-elevation mountain areas have broadleaf forests, manmade forests, bamboo groves, agricultural lands, and irrigation ponds in close proximity to towns and villages, and that these varied environments are home to 23 mammalian species.

A nurturing environment

Why do leopard cats choose to live so close to human habitations?

Because the grasslands, forests, and fields are full of the rodents, birds, and hares on which they prey, and the forests provide the cats with a protected environment in which to rear their young.

Many members of the Tongxiao Conservation Society have been in the business of growing economically important tree crops such as Formosan acacia and tung trees for years. The society itself is one of the few Miaoli groups actively engaged in agroforestry. With government conservation policies reducing lumber harvests, society members have been seeking to transition into other fields and have become involved with the Forestry Bureau’s “community forestry” program.

Yu Chien-hsun, a technician with the bureau’s Hsinchu Forest District Office, says that the bureau is gathering data for a leopard cat conservation zone in Miaoli. The society is in favor of the effort, but hopes it can be combined with community development.

On this afternoon, Chen is leading a group of conservation society members into Hsinchu’s No. 74 and 75 forest lands to conduct a survey. When they run into an animal trail, they begin boring into the forest and soon find a gray-white mass of leopard cat scat. Chen explains that leopard cats don’t bury their scat, instead using it and urine to mark their territories. She then reminds society members to bury whatever territorial markers they find after recording their location to avoid double counting.

Chen says that excrement serves multiple purposes for male leopard cats, who not only use it to mark territory, but also to attract females. She adds that leopard cats have quite large territories, with the males having home ranges of five to six square kilometers, and the females 1.5-1.8 km².

“If it weren’t for Chen’s research, we’d know almost nothing,” says Yu. He explains that development projects like the County Route 50 and Provincial Route 13 bypasses would have done great damage to the cats’ habitat if the environmental impact studies (EIS) hadn’t looked at Chen’s data. He mentions the Fulüshou Cemetery project in Houlong as another case in point. The Legislative Yuan and environmental groups have called for the EIS to be redone because the original didn’t examine the project’s impact on the leopard cats’ habitat. As a result, the project is still under negotiation.

Addicted to cats

Most animal experts have a story about how they ended up in the field. In Chen’s case, her study of leopard cats began with her love of cats in general.

Chen studied history as an undergraduate, but after graduation went to work providing care for animals in the Taipei Zoo’s Nocturnal Animal House. Though the two years she spent tending bobcats and leopard cats satisfied her desire to observe the cats up close, she came to realize that zoo work and conservation work were quite different. She went back to school, this time in the US, intending to write a master’s thesis on Taiwan’s cats. Since the Formosan clouded leopard was already extinct, she planned to focus on the leopard cat.

However, Kurtis Pei, a professor at NPUST from whom she sought advice, recommended that she expand her study to small carnivores more generally. He felt that there was so little information available on the leopard cat in Taiwan that Chen would need much more than two years to complete her thesis. She therefore also examined populations of small carnivorous mammals such as crab-eating mongooses and civets.

Chen had a scary moment while doing her master’s fieldwork: she nearly died after being stung more than 100 times by hornets. She saved herself by hiding in a river until the hornets dispersed. Unfortunately, she was not immediately put on dialysis or given a transfusion when she got to the hospital, and her kidneys failed. Her ordeal went on to include internal bleeding, ulcerations all over her body, and more than 20 days in an intensive care unit.

Even so, her passion for her research continued to burn. After completing her master’s degree, she came across animal rescue reports indicating that traces of leopard cats had been found in Miaoli and Nantou.

King of the mountain revealed

But even given that traces of leopard cats had been found in the low mountains stretching from Miaoli to Chiayi, how many were there? A population survey was needed. Chen decided to focus her PhD research specifically on the leopard cats of the low-elevation mountainous regions of Hsinchu and Miaoli.

Leopard cats are always on the move and studying them over a broad area requires infrared cameras with automated triggers. But Pei was able to secure funding from the Forestry Bureau in 2005, allowing Chen to set up cameras at 137 sample sites in Miaoli and 72 in Hsinchu. After three years, she had enough data to map the cats’ distribution.

She also captured and radio-tagged six cats in 2007–2008 so she could track their movements and learn when they are active and how far they roam.

“Leopard cats can really run,” she says. “We couldn’t keep up with them on our motorcycles.” She mentions that one of the cats she tracked—a male named A-shu—would range over as much as two to three square kilometers in the course of an evening. Every time Chen and her companion picked up the signal from his tag and stopped their motorcycles to get a good reading, A-shu would disappear again. Chen would quickly note their position, then take up the chase once again. Over the course of the night, A-shu ran them ragged.

Miaoli residents spot leopard cats fairly often, so Chen also passed around questionnaires. She found an elderly man who had seen a mother with four kittens, and a hunter who told her that the cats climb very well. Many residents also described how the cats hunt chickens: “They grab one, fling it over a shoulder, then strut away.”

Even after years of study, Chen is well aware that there’s still much to be learned about the cats’ habits, such as their breeding season, breeding behaviors, and how they rear their young, not to mention their distribution across other low-elevation mountainous areas and the problems they face therein.

Habitat destruction

Leopard cats are distributed throughout East and Southeast Asia in habitats that include tropical rainforests, coniferous forests, and semi-arid lands. They are both the most widespread and most adaptable of cats.

However, they face more severe environmental problems on the island of Taiwan than they do in their continental ranges. The foremost of these is habitat destruction through development. The planned Houlong cemetery is a case in point. Though only a few dozen hectares in area, the cemetery would cut across the cats’ range and greatly reduce the availability of prey.

Roads are another killer. In March of 2012, two leopard cats were killed on the same stretch of County Route 128 in Miaoli in just eight days.

Hunting and poisoning are also threats. Chen’s study of the six cats she tagged was cut short when five died in traps or by poisoning. Though heartbroken, there was little she could do except work harder to make the people of rural Miaoli aware that the cats are important, protected animals.

Fortunately, in recent years the Forestry Bureau and the Nature and Ecology Society of Miaoli have been actively pursuing conservation measures. The society has been working with fire departments to disseminate information on rescuing injured leopard cats and to build a poultry-farm notification system, a project which involves installing infrared cameras on farms and offering rewards for information on the cats. These efforts have markedly increased the reporting of injured cats and of cats killed by the roadside.

Conservationists are also hoping to have the leopard cat named a sort of mascot for Miaoli County, much as the Okinawan island of Iriomote has done with the endangered Iriomote cat (a subspecies of leopard cat). Iriomote has made the cat its tourism ambassador, posted signs on roads all over the island warning drivers to be careful, and created wildlife corridors. In addition, products from the island are all emblazoned with an image of the cat, much to the delight of tourists.

There’s no doubt that Taiwan’s most beautiful cat is up to the task of being Miaoli’s tourism ambassador. “Hiring” the leopard cat would do more than repair the cat’s fortunes. It would also go a long way towards conserving Taiwan’s low-elevation mountain ecosystems.

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