Abstract Hypothesized reasons for the decline of many woodrat populations in the eastern United States include parasitism by raccoon roundworm (Baylisascaris procyonis; Ascaridida: Ascarididae), hard mast shortages, owl predation, and reductions in suitable structures (e.g., rock crevices) for nest construction. We investigated whether abundance and apparent survival of eastern woodrats (Neotoma floridana) within a successfully reintroduced metapopulation in southern Illinois could be predicted by factors underlying these hypothesized reasons for woodrat declines. We analyzed capture histories of 205 eastern woodrats from eight rock outcrop sites in summers of 2013 and 2014 to estimate local population size and apparent survival. We then used repeated-measures models to test how woodrat abundance and apparent survival were associated with availability of mast trees, owl abundance, risk of raccoon roundworm infection, and crevice availability. Mean monthly estimated woodrat abundance at sites ranged from 0.78 to 21.58 in 2013 and 0.48 to 18.08 in 2014, while monthly apparent survival ranged from 0.00 to 0.76 during the summers and 0.05 to 0.90 during the trapping intersession. Crevice availability was positively associated both with abundance and apparent survival of woodrats. Our results did not support the hypothesis that owls reduce woodrat populations because woodrat abundance was positively associated with owl abundance across sites. No raccoon roundworm eggs were found at any site. We conclude that crevice availability was the best predictor of woodrat population success in our study area, while owl abundance may be a proxy for other habitat variables or a response to woodrat abundance. Our findings suggest measures that could be taken to benefit woodrat survival and abundance.

中文翻译：

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树木、猫头鹰、蠕虫和裂缝：哪些栖息地因素可以预测当地的林鼠人口统计？

摘要 美国东部许多林鼠种群减少的假设原因包括浣熊蛔虫（Baylisascaris procyonis；Ascaridida：Ascarididae）的寄生、硬桅杆短缺、猫头鹰捕食以及用于筑巢的合适结构（例如岩石裂缝）的减少. 我们调查了在伊利诺伊州南部成功重新引入的集合种群中东部林鼠 (Neotoma floridana) 的丰度和表观存活率是否可以通过这些假设的林鼠下降原因的因素来预测。我们分析了 2013 年和 2014 年夏天从八个岩石露头地点捕获的 205 只东部林鼠的历史，以估计当地种群规模和表观存活率。然后，我们使用重复测量模型来测试木鼠丰度和表观存活率与肥大树的可用性、猫头鹰丰度、浣熊蛔虫感染风险和缝隙可用性之间的关系。在 2013 年和 2014 年，平均每月估计的 Woodrat 丰度在 0.78 到 21.58 之间，在 0.48 到 18.08 之间，而在夏季，月表观存活率在 0.00 到 0.76 之间，在诱捕期间为 0.05 到 0.90。缝隙可用性与林鼠的丰度和表观存活率呈正相关。我们的结果不支持猫头鹰减少woodrat 种群的假设，因为woodrat 丰度与跨地点的猫头鹰丰度呈正相关。在任何地点均未发现浣熊蛔虫卵。我们得出的结论是，裂缝可用性是我们研究区域中林鼠种群成功的最佳预测指标，而猫头鹰丰度可能代表其他栖息地变量或对林鼠丰度的反应。我们的研究结果提出了可以采取的措施来有益于林鼠的生存和丰富。