Disturbances within many communities are common, but the recovery of riverine fish assemblages from anthropogenic fish kills is often not well documented. Quantification of fish community recovery is needed to assess how rapidly or whether recovery occurs without mitigation. To address this need, we evaluated the temporal dynamics of six streams located in central Illinois, including systems impacted by fish kills and an undisturbed reference system. We found species richness and the index of biotic integrity experienced dramatic shifts within the first year after the disturbance event, while fish density varied less within most streams. Interestingly, local extinctions following a kill event were not limited to only rare species, with some dominant components of the local community also lost. Some impacted streams experienced small compositional changes, similar to those within the reference system, while other streams experienced large and continued compositional shifts following disturbance. The rate of compositional change decreased significantly with time since disturbance in all locations, especially within the first year. Most metrics of recovery reached a level of relative stasis three years after the disturbance event. Based on this, we recommend disturbed streams should be monitored for at least three years to fully document recovery dynamics and to determine whether active restoration efforts are warranted. Streams which do not recover during this time frame will likely require direct intervention to achieve recovery. Our results also highlight the importance of regular stream monitoring to document a stream's baseline composition and dynamics if a disturbance were to occur.

中文翻译：

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人为干扰后河流鱼类种群的恢复

许多社区内的干扰很常见，但是从人为杀灭鱼类中恢复河流鱼类组合的记录却很少。需要对鱼类群落的恢复进行量化，以评估恢复的速度或是否在不缓解的情况下进行。为了满足这一需求，我们评估了位于伊利诺伊州中部的六条河流的时间动态，包括受鱼类杀害影响的系统和不受干扰的参考系统。我们发现，在干扰事件发生后的第一年内，物种丰富度和生物完整性指数发生了巨大变化，而大多数溪流中的鱼类密度变化较小。有趣的是，杀戮事件后的局部灭绝不仅限于稀有物种，还失去了当地社区的一些主要组成部分。与参考系统内的流相似，一些受影响的流的成分变化较小，而其他流则在干扰后经历较大且持续的成分变化。自从所有地区发生骚扰以来，成分变化的速率均随时间显着下降，尤其是在第一年内。干扰事件发生三年后，大多数恢复指标达到了相对静止状态。基于此，我们建议对受干扰的流进行至少三年的监控，以完整记录恢复动态并确定是否需要积极进行恢复工作。在此时间段内未恢复的流可能需要直接干预才能实现恢复。我们的结果还强调了定期进行流监控以记录流的重要性。