Abstract Amphibians are declining worldwide due to habitat destruction, disease, and environmental stressors. Extremely variable breeding populations and a paucity of long-term monitoring data limits rigorous testing of amphibian population trends, or bias associated with sampling regimes. We used 24 years of continuous trapping data to compare annual probability of presence, and population trends and statistical power for six species among seven wetlands using five sampling scenarios (SS) based on the interval and span of years analyzed. Richness within a year and wetland ranged 29–89% of total species captured there (all years), and 27–82% of total species captured during the study (all years, pooled wetlands). SS had little effect on probability of presence for most common species but did for less common species. Population trends were inconsistently significant or nonsignificant among wetlands within SSs, and among SSs within the same wetlands. The direction (+/−) of trends among wetlands and scenarios for a species generally agreed, but not always. Low statistical power for virtually all population trend estimates, including the All-years SS indicated results were inconclusive. Juvenile recruitment was correlated with adult populations in some subsequent years for four of the six species. We illustrate how probability of presence and population trend estimates can differ among similar wetlands within a landscape, and according to the span, or subset of years sampled. Our results indicate that amphibian monitoring at wetlands cannot conclusively gauge population trends for breeding populations that fluctuate widely among wetlands and from year to year.

中文翻译：

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湿地的长期两栖动物监测缺乏检测种群趋势的能力

摘要 由于栖息地破坏、疾病和环境压力因素，世界范围内的两栖动物数量正在减少。极端可变的繁殖种群和缺乏长期监测数据限制了对两栖动物种群趋势或与采样制度相关的偏差的严格测试。我们使用 24 年的连续诱捕数据，根据分析的年份间隔和跨度，使用五种抽样方案 (SS)，比较了 7 个湿地中 6 个物种的年度存在概率、种群趋势和统计功效。一年内和湿地的丰富度占那里捕获的物种总数的 29-89%（所有年份），占研究期间捕获的物种总数的 27-82%（所有年份，汇集湿地）。SS 对大多数常见物种的存在概率几乎没有影响，但对不太常见的物种有影响。SS 内的湿地之间以及同一湿地内的 SS 之间的人口趋势不一致显着或不显着。湿地之间趋势的方向 (+/-) 和物种的情景普遍一致，但并非总是如此。几乎所有人口趋势估计的低统计功效，包括 All-year SS 表明结果是不确定的。对于六个物种中的四个，幼年招募与随后几年的成年种群相关。我们说明了景观中类似湿地的存在概率和人口趋势估计如何不同，并根据跨度或采样年份的子集。我们的结果表明，湿地的两栖动物监测不能最终衡量在湿地之间和每年之间波动很大的繁殖种群的种群趋势。