Linking removal targets to the ecological effects of invaders: a predictive model and field test
Linking removal targets to the ecological effects of invaders: a predictive model and field test
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DOI：
10.1890/13-0979.1
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发表时间：
2014-09-01
影响因子：
5
通讯作者：
Cote, Isabelle M.
中科院分区：
文献类型：
--
作者：
Green, Stephanie J.;Dulvy, Nicholas K.;Cote, Isabelle M.
物种入侵对受害生态系统产生一系列负面影响，其中许多发生的规模和程度无法完全根除。当利用可用的管理资源不可能完全灭绝时，有效的策略可能是将入侵种群抑制到预计会导致不良生态变化的水平以下。我们通过制定和测试控制西大西洋珊瑚礁上入侵的印度太平洋狮子鱼（Pterois volitans 和 P.miles）的目标来说明这种方法。我们首先开发了狮子鱼对本地鱼类群落捕食的规模结构模拟模型，我们用该模型来预测狮子鱼的阈值密度，超过该阈值密度，本地鱼类生物量就会下降。然后，我们通过实验控制狮子鱼密度高于或低于珊瑚礁特定阈值，并在 18 个月内监测对 24 个巴哈马斑块珊瑚礁本地鱼类种群的影响，来测试我们的预测。我们发现，将狮子鱼减少到预测阈值密度以下，可以有效保护本地鱼类群落生物量免受捕食引起的下降。根据珊瑚礁的情况，需要将密度降低 25-92%，以将狮子鱼抑制到预计会过度消耗猎物的水平以下。在狮子鱼密度低于阈值的珊瑚礁上，本地猎物鱼的生物量增加了 50-70%。到实验结束时，小型动物（总长 15 厘米）的增益，包括生态上重要的食草动物和经济上重要的渔业物种，增加了 10-65%。至关重要的是，在部分和全部清除狮子鱼的珊瑚礁上，猎物鱼生物量也实现了类似的增长，但部分清除的实施时间减少了 30%。相比之下，狮子鱼密度超过珊瑚礁特定阈值的所有珊瑚礁上，小型本地鱼类的生物量下降了 50% 以上。在研究开始时，礁石间被捕食鱼类生物量的巨大差异影响了狮子鱼的阈值密度，这意味着我们无法确定指导控制工作的单一经验法则。然而，我们的模型提供了一种使用当地监测数据设定珊瑚礁特定目标以控制种群的方法。我们的工作首次证明，对于持续的入侵，将入侵者抑制到造成环境损害的密度以下，可以在保护局部范围内的本地生态系统方面产生类似的效果，从而实现彻底根除。
Species invasions have a range of negative effects on recipient ecosystems, and many occur at a scale and magnitude that preclude complete eradication. When complete extirpation is unlikely with available management resources, an effective strategy may be to suppress invasive populations below levels predicted to cause undesirable ecological change. We illustrated this approach by developing and testing targets for the control of invasive Indo-Pacific lionfish (Pterois volitans and P. miles) on Western Atlantic coral reefs. We first developed a size-structured simulation model of predation by lionfish on native fish communities, which we used to predict threshold densities of lionfish beyond which native fish biomass should decline. We then tested our predictions by experimentally manipulating lionfish densities above or below reef-specific thresholds, and monitoring the consequences for native fish populations on 24 Bahamian patch reefs over 18 months. We found that reducing lionfish below predicted threshold densities effectively protected native fish community biomass from predation-induced declines. Reductions in density of 25-92%, depending on the reef, were required to suppress lionfish below levels predicted to overconsume prey. On reefs where lionfish were kept below threshold densities, native prey fish biomass increased by 50-70%. Gains in small (15 cm total length), including ecologically important grazers and economically important fisheries species, had increased by 10-65% by the end of the experiment. Crucially, similar gains in prey fish biomass were realized on reefs subjected to partial and full removal of lionfish, but partial removals took 30% less time to implement. By contrast, the biomass of small native fishes declined by >50% on all reefs with lionfish densities exceeding reef-specific thresholds. Large inter-reef variation in the biomass of prey fishes at the outset of the study, which influences the threshold density of lionfish, means that we could not identify a single rule of thumb for guiding control efforts. However, our model provides a method for setting reef-specific targets for population control using local monitoring data. Our work is the first to demonstrate that for ongoing invasions, suppressing invaders below densities that cause environmental harm can have a similar effect, in terms of protecting the native ecosystem on a local scale, to achieving complete eradication.