Feral horse (Equus ferus caballus) populations on public rangelands in the western United States threaten forage production for livestock and wildlife habitat. Interference competition between feral horses and heterospecifics at watering sources can have negative effects on livestock and wildlife. Researchers have documented altered timing and behavior of wild ungulates at water sources when horses were present. The few studies examining these interactions have infrequently occurred within areas specifically managed for feral equids and have not occurred in sites with cattle. We used motion-sensitive cameras at 8 watering sources to document watering activity patterns and construct indices of temporal overlap among feral horses, cattle, elk (Cervus canadensis), mule deer (Odocoileus hemionus), and pronghorn (Antilocapra americana) within the Adobe Town Herd Management Area in southern Wyoming, USA, between June and September 2018 and 2019. Feral horses, cattle, and pronghorn exhibited a high degree of temporal overlap (>79%) in water use, with feral horses and pronghorn exhibiting the highest estimated percent overlap (88.1%, 95% CI = 86.5–89.6%). Mule deer and elk watering activity also overlapped with horses and cattle but to a lesser degree (<55%). Feral horses spent a mean of 16.7 ± 30.5 (SD) minutes during a watering event and were present at a given water source on average 4.5 ± 6.3% and up to 34.9% of the day, which is less than reported in previous studies. Cattle spent on average 23.5 ± 44.9 minutes during a watering event, and were present on average 4.2 ± 7.7% and up to 42.4% of the day at a single water source. Results of generalized linear mixed-effects models indicated that number of conspecifics was the strongest predictor of visit duration for pronghorn and horses; hour of the day and group size of heterospecifics were informative, but less important, variables. There was no difference in peak visitation time for any species between sites of high versus low horse or cattle use. Despite temporal overlap, we did not find evidence of interference competition between feral horses, cattle, and pronghorn. We recommend future examination of interference competition and its biological consequences between introduced and native ungulates at water sources of varying size across sites, equid population levels, and livestock stocking rates. © 2020 The Wildlife Society.

中文翻译：

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水源地野马、牛和本地有蹄类动物的时间重叠

美国西部公共牧场上的野马（Equus ferus caballus）种群威胁着牲畜和野生动物栖息地的饲料生产。野马和水源异种之间的干扰竞争会对牲畜和野生动物产生负面影响。研究人员记录了当马在场时野生有蹄类动物在水源中的时间和行为的改变。少数研究这些相互作用的研究很少发生在专门管理野生马科动物的地区，也没有发生在有牛的地方。我们在 8 个浇水源使用运动敏感相机来记录浇水活动模式，并构建野马、牛、麋鹿（加拿大鹿）、骡鹿（Odocoileus hemionus ) 和叉角羚 ( Antilocapra americana) 在美国怀俄明州南部的 Adob​​e Town Herd Management Area，2018 年 6 月至 9 月和 2019 年之间。野马、牛和叉角羚在用水方面表现出高度的时间重叠 (>79%)，野马和叉角羚表现出最高的估计重叠百分比（88.1%，95% CI = 86.5–89.6%）。骡鹿和麋鹿的浇水活动也与马和牛重叠，但程度较小（<55%）。野马在一次浇水事件中平均花费 16.7 ± 30.5 (SD) 分钟，平均每天有 4.5 ± 6.3% 和高达 34.9% 的时间出现在给定的水源，这比之前的研究报告的要少。牛在一次浇水事件中平均花费 23.5 ± 44.9 分钟，平均每天 4.2 ± 7.7% 和高达 42.4% 的时间出现在单一水源。广义线性混合效应模型的结果表明，同种数量是叉角羚和马访问持续时间的最强预测因子；一天中的小时数和异种特异性的组大小是提供信息但不太重要的变量。在马或牛使用量高与低的地点之间，任何物种的高峰访问时间没有差异。尽管有时间重叠，但我们没有发现野马、牛和叉角羚之间干扰竞争的证据。我们建议未来检查不同地点、不同种群数量和牲畜存栏率的水源中引入和本地有蹄类动物之间的干扰竞争及其生物学后果。© 2020 野生动物协会。