I used 20 years of sampling data to describe the dynamics of the invasion of the rusty crayfish, Faxonius rusticus (Girard, 1852), of two stream systems in New York state (USA) and compare this invasion to invasions of this species of lakes elsewhere in North America. Rusty crayfish typically increased rapidly in abundance while displacing native crayfishes, becoming > 90% of crayfish captured in an average of 9 years. As in lakes, overall crayfish abundance increased as the invasion progressed. The F. rusticus population spread at a median rate of 3 km yr–1 upstream and 8.1 km yr–1 downstream. The hypothesis that an Allee effect would occur at the invasion front was not supported, since the rate of change of F. rusticus abundance did not increase as the invasion progressed. Qualitatively, the dynamics of F. rusticus’s invasion of streams are similar to previous findings for lakes, suggesting that the main processes affecting the invasions are similar.

中文翻译：

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美国纽约州两个河流系统生锈的小龙虾 Faxonius rusticus (Girard, 1852) (十足目: Astacidea) 的入侵动态

我使用了 20 年的采样数据来描述生锈的小龙虾 Faxonius rusticus (Girard, 1852) 入侵纽约州（美国）两个河流系统的动态，并将这种入侵与其他地方这种湖泊的入侵进行了比较在北美。生锈的小龙虾通常数量迅速增加，同时取代本地小龙虾，变得 > 平均 9 年捕获 90% 的小龙虾。与湖泊一样，随着入侵的进行，小龙虾的总体数量增加。F. rusticus 种群以上游 3 公里 yr-1 和下游 8.1 公里 yr-1 的中位数传播。不支持在入侵前沿会发生 Allee 效应的假设，因为 F. rusticus 丰度的变化率没有随着入侵的进展而增加。定性地，F的动力学。