狩獵與危害防治對臺灣野豬(Sus scrofa taivanus)族群影響之探討

Impact of hunting and crop damage prevention on Formosan wild boar (Sus scrofa taivanus) population

吳幸如(Hsin-Ju Wu)

指導教授 ： 王穎

國立臺灣師範大學/理學院/生命科學系/博士(2009年)

摘要

野生動物保育法自從在1989年公告實施後，近年來許多研究已顯示多數保育類野生動物種數量因此穩定增加中，但中大型哺乳動物中唯一未列名於保育類野生動物名錄中的臺灣野豬(Sus scrofa taivanus)，卻不明原因明顯減少。由於野豬是廣受歡迎的山產，牠獨特的拱地行為也會破壞農作物，是否因此使得其與人之間的衝突性高於其他物種，而增加了獵捕壓力、導致族群下降，值得深入探討。而野豬一向是台灣山林很重要的自然資源，為能永續利用，了解其族群現況、探討族群減少的原因是否與未受法規保護，以及與人之衝突(包括危害作物及遭受過度獵捕)嚴重有關，乃十分重要。
本研究主要包括四大章節，首先藉由過去相關文獻之結果整理出野豬特有的生物特性如何影響人類對其捕殺的動機，也由1993~2007年間相關野生動物調查文獻之次級資料整理與獵人訪問資料，比較野豬與其他大型保育類物種--台灣獼猴(Macaca cyclopis)、臺灣山羌(Muntiacus reevesi micrurus)、臺灣長鬃山羊(Naemorhedus swinhoei) 與臺灣水鹿(Capricirnis crispus swinhoei))之相對數量，來了解其近年來之族群動態。文獻整理結果，野豬容易受人獵捕的特質可能因其與家豬同種，肉質同受人類青睞，加上其以特有鼻骨掘土之拱地行為與喜歡在平坦農地活動之特性，容易引發與人之衝突。在族群動態方面，比較兩類資料分析結果，皆顯示野豬與水鹿數量同屬其中最低等級，顯著低於保育類物種山羌、獼猴與長鬃山羊，確實值得注意。
其次，研究者於2003.8~2006.10年間以深度訪談法與半開放問卷訪問為主、自然觀察法為輔，在野豬族群明顯減少之花蓮、南投、台東、高雄與屏東五縣山區，分別以滾雪球取樣法與分層隨機取樣法對當地經常狩獵獵人與受危害農民進行野豬狩獵與危害現況調查。結果顯示受訪野豬獵人以年齡在36-55歲間之中年人最多，其中有23 %只獵捕野豬一種獵物。最常使用鐵夾及吊子在海拔600-1600m之山區狩獵，但青年獵人顯著偏好槍獵。而從危害現況調查結果中發現，雖然野豬對玉米、地瓜及芋頭等作物危害較為嚴重外，但除部份地區之玉米外，皆非受訪農民主要作物，加上近十年捕獲之危害野豬數量也有愈來愈少的趨勢，顯示野豬危害嚴重程度可能因其數量減少而減輕；但不論受害是否嚴重，受訪農民均顯著偏好以獵殺法來防治其危害，其中又以獵狗團圍獵的效果最好。另在高雄梅山地區以胃內含物與排遺顯微分析進行農地與遠農地之野豬食性比較，發現兩者間的種類並未重疊，顯示森林深處活動之野豬應不會到農地覓食而造成危害。
接著為進一步分析影響選擇狩獵野豬之因子，研究者在2002.5~2006.10間以深度訪談與參與觀察法在桃源鄉梅山地區記錄當地使用索套或獵槍之狩獵事件中獵獲之物種、成功率與地點中之農地比例等，結果顯示該地狩獵事件發生之季節間與是否為農地均無顯著差異。但獵獲物種以野豬與山羌數量顯著偏高，其中又以獵槍法顯著獵獲較多野豬。而以穿越線調查法在該區狩獵頻度與動物相對數量時，發現山羌數量顯著高於野豬，顯示野豬在當地被選擇性獵捕。另由訪查發現當地野保法之執法偏重物種保育，對野豬族群之幫助並不大。最後，藉由對獵人之深度訪問調查與次級資料整理，發現野豬肉的販售價格是十年來唯一有增加趨勢的大型野生動物，經濟價值也影響其狩獵偏好。而文化價值的調查結果，也顯示野豬在原住民的生活中仍扮演重要角色。

關鍵字

臺灣野豬 ； 野生動物保育法 ； 一般類野生動物 ； 狩獵 ； 危害防治 ； 人豬衝突 ； 價值 ； 保育

並列摘要

Recently many studies had indicated that many protected wildlife species have been increasing steadily since the legistation of the “Wildlife Conservation Law” in 1989. With exception, abundance of Formosan wild boar (Sus scrofa taivanus), the only non-protected large mammal in Taiwan, has been decreasing for unknown reason. Whether the nature as popular game sold at store or as a nauseating pest for cropland was responsible for its heavy hunting pressure and population status or not, it has never been known. For this reason, this study investigated the population trend, hunting and crop damage pattern of the species and examined the relationship between theses factors. This should be beneficial to the sustainable management of this special, valuable creature.
This study contains four main parts. First, by reviewing previous, related works, I tried to find out the motivation of hunting wild boar as related to its natural habitat. I collected information about the relative abundance of wild boar along with other four large mammals, Formosan macaque (Macaca cyclopis), Formosan muntjac (Muntiacus reevesi micrurus), and Formosan serow (Naemorhedus swinhoei), and Formosa sambar (Capricirnis crispus swinhoei), from the papers published during 1993-2007, to compare their population trend for the past two decades. Results showed that the boar was heavily hunted for its meat as domestic pig and for its ability in seriously ruining massive crop product by rooting. Based on reviewed data, it was indicated that sambar and wild boar were ranked in lower abundance than the remaining three animals in recent years.
Second, from August 2003 to October 2006, deep-interview and helf-opened questionnaire interview, ntural observation were conducted at Huelien, Nantou, Taitong, Kaoshiung, and Pingtung Counties, where the number of wild boar was largely reduced. A snow-balling sampling and stratified sampling were applied to document the pattern of crop damage and boar-hunting by local hunters and farmers. Most hunters aged between 36 and 55, and 23 % of them hunted boar exclusively. They set leg-hold traps and snares in mountain of 600-1600 m in elevation. Younger hunters preferred to hunt with musket. Among those raided crop plants like corn, sweet potato, and taro, only was corn was major crop for some areas. However, crop damage problem may become milder as a consequence of boar’s decreased number for the past decade. But interviewed farmers favored lethal control, with dog-chasing being claimed most effective, even though the farmers suffered with minor crop damage. Analysis of stomach content and dropping showed slim chance for boars to forage both at forest and farmland on Meishan of Kaoshiung County.
To further analyze factors influencing the reason why boars were hunted, another deep-interview and participant observation were conducted at Meishan village to determine the differences in capture rate, species hunted and location among hunting methods such as leg-hold sanre trap and traditional musket. It was found that wild boar and muntjac were captured in greater amount than other species. Overall, a greater number of wild boars were captured by musket. And because muntjac outnumbered wild boar by transectline sampling, it is suggested that wild boar was selectively hunted. Law enforcement on protected animals apparently did not help in preserving wild boar in areas such as national forest and park where hunting is restricted. For the past decade, market price of large mammal bushmeat increased for the boar exclusively. This coincides with its preference by hunter in my data. Undoubtedly this species still plays a crucial role on the modern living of indigenous people nowadays.

並列關鍵字

Formosan wild boar ； Sus scrofa taivanus ； hunting ； crop damage prevention ； man-boar conflict ； value ； law enforcement ； conservation

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