How often are invasion-induced ecological impacts missed?
How often are invasion-induced ecological impacts missed?
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DOI：
10.1007/s10530-013-0570-4
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发表时间：
2014-05-01
影响因子：
2.9
通讯作者：
Hewitt, Chad L.
中科院分区：
文献类型：
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作者：
Davidson, Alisha Dahlstrom;Hewitt, Chad L.
管理人员和决策者依靠经验研究来指导和支持减轻引进物种影响的生物安保措施。对该知识库有贡献的研究通常使用零假设显著性检验来确定数据模式的显著性。然而，依赖传统的统计显著性检验方法，加上许多影响研究固有的小效应和样本量以及大变异性，可能会掩盖对本土物种、群落或生态系统的影响。这可能会导致错误的确定性没有影响。我们调查了潜在的II型错误率和影响大小的31个非显着的经验评估的影响，引进藻类和甲壳类物种。我们发现，低功效始终导致接受II型错误的比率是I型错误的5.6-19倍（尽管效应量中等至大）。我们的研究结果表明，引入物种的影响研究具有统计学上不显著的结果（通常解释为“无影响”）可能会有很大的影响，由于小样本或效应大小和/或高变异而错过。这种令人担忧的“错过”影响的意愿对保护工作产生了严重影响，包括对物种影响的管理不足和对第二类错误的成本的低估。
Managers and policy makers depend on empirical research to guide and support biosecurity measures that mitigate introduced species' impacts. Research contributing to this knowledge base generally uses null hypothesis significance testing to determine the significance of data patterns. However, reliance on traditional statistical significance testing methods, combined with small effect and sample size and large variability inherent to many impact studies, may obscure effects on native species, communities or ecosystems. This may result in false certainty of no impact. We investigated potential Type II error rates and effect sizes for 31 non-significant empirical evaluations of impact for introduced algal and crustacean species. We found low power consistently led to acceptance of Type II errors at rates 5.6-19 times greater than Type I errors (despite moderate to large effect sizes). Our results suggest that introduced species for which impact studies have statistically non-significant outcomes (often interpreted as "no impact") may potentially have large impacts that are missed due to small sample or effect sizes and/or high variation. This alarming willingness to "miss" impacts has severe implications for conservation efforts, including under-managing species' impacts and discounting the costs of Type II errors.