In North America, wild pigs (Sus scrofa; feral pigs, feral swine, wild boars) are a widespread exotic species capable of creating large‐scale biotic and abiotic landscape perturbations. Quantification of wild pig environmental effects has been particularly problematic in northern climates, where they occur only recently as localized populations at low densities. Between 2016 and 2017, we assessed short‐term (within ~2 yrs of disturbance) effects of a low‐density wild pig population on forest features in the central Lower Peninsula of Michigan, USA. We identified 16 8‐ha sites using global positioning system locations from 7 radio‐collared wild pigs for sampling. Within each site, we conducted fine‐scale assessments at 81 plots and quantified potential disturbance by wild pigs. We defined disturbance as exposure of overturned soil, often resulting from rooting behavior by wild pigs. We quantified ground cover of plants within paired 1‐m² frames at each plot, determined effects to tree regeneration using point‐centered quarter sampling, and collected soil cores from each plot. We observed less percent ground cover of native herbaceous plants and lower species diversity, particularly for plants with a coefficient of conservatism ≥5, in plots disturbed by wild pigs. We did not observe an increase in colonization of exotic plants following disturbance, though the observed prevalence of exotic plants was low. Wild pigs did not select for tree species when rooting, and we did not detect any differences in regeneration of light‐ and heavy‐seeded tree species between disturbed or undisturbed plots. Magnesium and ammonium content in soils were lower in disturbed plots, suggesting soil disturbance accelerated leaching of macronutrients, potentially altering nitrogen transformation. Our study suggested that disturbances by wild pigs, even at low densities, alters short‐term native herbaceous plant diversity and soil chemistry. Thus, small‐scale exclusion of wild pigs from vulnerable and rare plant communities may be warranted. © 2020 The Wildlife Society.

中文翻译：

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野猪干扰对森林植被和土壤的影响

在北美，野猪（Sus scrofa; 野生猪，野生猪，野猪）是一种广泛的外来物种，能够造成大规模的生物和非生物景观干扰。在北部气候中，对野猪环境影响的量化尤其成问题，在北部气候中，它们仅在最近以低密度的局部种群出现。在2016年至2017年之间，我们评估了低密度野猪种群对美国密歇根州中下游半岛中部森林特征的短期（约2年之内）影响。我们使用全球定位系统的位置从7头放射性领野生猪中识别出16个8公顷的地点进行采样。在每个站点内，我们对81个样地进行了精细评估，并量化了野猪的潜在干扰。我们将干扰定义为暴露于翻倒的土壤，这通常是由野猪生根引起的。²在每个样地上绘制框架，使用点为中心的四分之一采样确定对树木再生的影响，并从每个样地收集土壤核心。我们观察到天然草食植物的地被植物百分比降低，物种多样性降低，特别是对于保守系数≥5的植物，在受到野猪干扰的地块中。尽管观察到的外来植物患病率很低，但我们并未观察到干扰后外来植物定植的增加。生猪生根时没有选择树种，我们也没有发现受干扰或不受干扰的地块在轻种子和重种子树种再生方面没有任何差异。在受干扰的地块中，土壤中的镁和铵含量较低，表明土壤扰动会加速大量养分的淋溶，从而可能改变氮的转化。我们的研究表明，即使在低密度下，野猪的干扰也会改变短期的天然草本植物多样性和土壤化学性质。因此，可能有必要将野生猪从脆弱和稀有植物群落中小范围地排除。©2020野生动物协会。