Permeability of three-strand electric fences by black bears and grizzly bears
Permeability of three-strand electric fences by black bears and grizzly bears
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黑熊、灰熊对三股电围栏的渗透性
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发表时间：
2018
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通讯作者：
B. Johnson
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作者：
B. Johnson
几十年来，北美一直使用电子围栏来威慑熊。生产商已经将至少五根电线的电网作为他们的主要解决方案，以减少对牲畜的掠夺，并减少对鸡舍和牛栏的袭击。然而，这些设计是昂贵的，将设计中使用的导线数量减少到三根导线将是有益的。缺乏对三线电子围栏在威慑熊方面的效果的科学评估。2015年和2016年，我在蒙大拿州的黑脚谷进行了一项研究，以评估快速部署电子围栏设计在阻止熊远离诱饵围栏方面的效果。在研究区域的20个地点建立了两种围栏配置的诱饵围栏。每个围栏被系统地通电和停电3天；进入围栏的通道被跟踪摄像机监测，以提供有关有效性和渗透性的信息。在2015年和2016年的学习季节，我记录了134次熊对栅栏围栏的访问。在这些访问中，78次发生在2015年，其中包括57只黑熊和21只灰熊。2016年发生了56次造访，包括34只黑熊和22只灰熊。黑熊和灰熊在没有通电的情况下，分别有48%(95%CI：32.0-63.6)和23%(5.0-53.8)的时间成功地越过了短栅栏。当短栅栏被激活时，黑熊的传球成功率为7%(0.2-33.9)，而灰熊的传球成功率为25%(5.5-57.2)。在没有通电的情况下，这两个物种在58%(95%CI：27.7-84.8)的尝试中都成功地通过了高墙设计。黑熊和灰熊分别在30%(95%CI：13.2-52.9)和0%(95%CI：0.0-45.9)的尝试中成功地进入高栅栏的带电围栏。这两种类型的围栏都阻止熊进入有诱饵的围栏，所有围栏在没有通电时都不允许完全进入，这表明即使是极简主义的电子围栏也可能成为黑熊和灰熊的障碍。需要进一步研究评估迅速增加的电子围栏建设的影响，以评估景观水平对熊的活动和栖息地选择的影响。
Electric fencing has been used to deter bears in North America for several decades. Producers have turned to a design of a minimum of five-wire electric fence as their primary solution to reduce livestock depredation and to reduce raids of chicken houses and beeyards. However, these designs are expensive and reducing the number of wires used in a design to three wires would be beneficial. Scientific evaluations of the efficacy of three-wire electric fencing at deterring bears is lacking. In 2015 and 2016, I conducted a study in the Blackfoot Valley of Montana to evaluate the efficacy of rapiddeployment electric fencing designs in deterring bears from baited enclosures. Baited enclosures of two fencing configurations were established at 20 sites in the study area. Each enclosure was systematically energized and unenergized for 3-day periods; and passage into the enclosure was monitored with trail cameras to provide information on effectiveness and permeability. I recorded 134 visits by bears to fenced enclosures during the study seasons of 2015 and 2016. Of these visits, 78 occurred in 2015 and included 57 black bears and 21 grizzly bears. Fifty-six visits occurred in 2016, including 34 black bears and 22 grizzly bears. Black bears and grizzly bears were successful at passing the short fence 48% (95% CI: 32.0 – 63.6) and 23% (5.0 – 53.8) of the time, respectively, when it was not energized. When the short fence was energized, black bears were 7% (0.2 – 33.9) successful in passing, whereas grizzly bears were successful in 25% (5.5 – 57.2) of attempts. When not energized, both species successfully passed the tall fence design in 58% (95% CI: 27.7 – 84.8) of attempts. Black bears and grizzly bears successfully entered energized enclosures with tall fences in 30% (95% CI: 13.2 – 52.9) and 0% (95% CI: 0.0 – 45.9) of attempts, respectively. Both fence types deterred bears from entering baited enclosures and all fences allowed less than perfect access when unenergized, suggesting that even minimalistic configurations of electric fences may act as barriers to black and grizzly bears. Further study evaluating the effects of rapidly increasing construction of electric fencing is needed to assess landscape level effects on bear movement and habitat selection.