Non-native earthworms found in Eastern Canada substantially affect soil properties and plant diversity, but less is known about their impacts on higher faunal species. We investigated the effects of non-native earthworms on populations of Plethodon cinereus, a common woodland salamander. We hypothesized that earthworms could adversely affect P. cinereus by consuming the forest floor, thereby decreasing soil moisture and the abundance of native preys. Conversely, earthworms could positively affect P. cinereus by providing refuge in their abandoned burrows and by being a novel prey. We installed 25 coverboards in 38 mature sugar maple (Acer saccharum) forests, 24 of which were earthworm-free. Over the next two years, we monitored earthworm and salamander populations using hot mustard extractions and visible implant elastomers, respectively. At a subset of four sites, two with and two without earthworms, we determined salamander diets in the spring (May–June), summer (July–August) and fall (September–October) seasons, using gastric lavage techniques. Forest floor depth decreased, whereas population density, body size and total prey volume of P. cinereus increased, with earthworm abundance. Earthworms, which are soft-bodied and nutritious prey, composed most of the salamander diet at sites with earthworms, volumetrically accounting for > 50% of total prey volume. Despite this, we found fewer prey items in the stomach of salamanders at earthworm-invaded sites, indicating that salamanders are getting a higher caloric intake per feeding while expending less energy. We conclude that non-native earthworms have a net beneficial effect on P. cinereus populations in Eastern Canada, mainly by improving diet quality.

加拿大东部发现的非本地蚯蚓极大地影响了土壤特性和植物多样性，但人们对其对高等动物物种的影响知之甚少。我们研究了非本地蚯蚓对Plethodon cinereus （一种常见的林地蝾螈）种群的影响。我们假设蚯蚓可能通过消耗森林地面来对灰松鼠产生不利影响，从而降低土壤湿度和本地猎物的丰度。相反，蚯蚓可以通过在废弃的洞穴中提供避难所并成为新的猎物来对灰雉鱼产生积极影响。我们在 38 个成熟的糖枫林中安装了 25 个覆盖板，其中 24 个没有蚯蚓。在接下来的两年里，我们分别使用热芥末提取物和可见的植入弹性体监测蚯蚓和蝾螈的数量。在四个地点的子集中，两个有蚯蚓，两个没有蚯蚓，我们使用洗胃技术确定了春季（五月至六月）、夏季（七月至八月）和秋季（九月至十月）季节的蝾螈饮食。森林地表深度减小，灰雉种群密度、体型和猎物总量增加，蚯蚓丰富。蚯蚓是软体且营养丰富的猎物，是有蚯蚓的地点蝾螈的大部分食物，其体积占猎物总体积的 50% 以上。尽管如此，我们在蚯蚓入侵的地点发现蝾螈胃中的猎物较少，这表明蝾螈每次进食时摄入的热量较高，而消耗的能量较少。我们得出的结论是，非本地蚯蚓对P. 主要通过改善饮食质量来减少加拿大东部的灰雉种群。