Fenner School of Environment and Society, The Australian National University, Canberra, Australian Capital Territory, 2601, Australia.
Centre of Excellence for Environmental Decisions, Centre for Biodiversity and Conservation Science, The University of Queensland, St Lucia, Queensland, 4072, Australia.
Ecol Appl. 2019 Apr;29(3):e01846. doi: 10.1002/eap.1846. Epub 2019 Mar 5.
Overabundant native animals cause a variety of human-wildlife conflicts that can require management to reduce their social, environmental, or economic impacts. Culling is an intuitively attractive management response to overabundance, but poor monitoring of results and costs means that evidence for successful outcomes is often lacking. Furthermore, many culls worldwide have been ineffective or counterproductive due to ecological release mechanisms or compensatory responses by the overabundant species. We completed a controlled, replicated, costed, and rigorously monitored experimental cull of the endemic Australian honeyeater, the Noisy Miner (Manorina melanocephala). Aggressive exclusion of birds from remnant woodland patches by overabundant Noisy Miners is listed as a Key Threatening Process under Australian conservation legislation due to its impacts on threatened birds. The problem is particularly prevalent in the highly modified agricultural landscapes of eastern Australia. The species impacts avian assemblages at low densities (0.6-0.8 birds/ha) and at a subcontinental scale (>1 million km ). Some ecologists recommend culling as the only management response capable of timely reversal of declines of threatened small woodland birds. We monitored Noisy Miner abundance before and for 12 months after a culling program and found that immediate recolonization from the surrounding landscape negated the impact of the cull. We hypothesize that this is due to a vacuum effect; whereby, birds resident in more marginal habitat around treatment patches move into the vacant territory post-cull. Modeled mean abundance of Noisy Miners declined by 22% in treatment sites compared to an increase of 4% in control sites in the post-cull period. Abundance in all sites, however, remained three to five times higher than published ecological impact thresholds. Return on investment analysis indicated no relationship between culling effort and reduction in Noisy Miner abundance. We conclude that culling at a patch scale is not an efficient method of reducing Noisy Miner abundance to levels unlikely to impact threatened woodland birds in the highly modified study landscape, despite estimated costs 18 times lower than another potential management response of revegetation. Our study highlights the importance of building empirical evidence before intuitively attractive but not necessarily ecologically effective management responses are applied more widely.
过剩的本地动物会引发各种人类与野生动物的冲突，这些冲突可能需要加以管理，以降低其对社会、环境或经济的影响。扑杀是一种本能上吸引人的过度繁殖管理对策，但由于对结果和成本的监测不佳，成功结果的证据往往缺乏。此外，由于生态释放机制或过度繁殖物种的补偿反应，世界范围内许多扑杀行动都没有效果或适得其反。我们对澳大利亚特有蜂蜜鸟——嘈杂矿工（Manorina melanocephala）进行了一项受控的、重复的、有成本的、经过严格监测的实验性扑杀。由于过度繁殖的嘈杂矿工对受威胁鸟类的影响，它们将鸟类从残余林地斑块中驱逐出去的行为被澳大利亚保护立法列为关键威胁过程。由于该问题在澳大利亚东部高度改造的农业景观中尤为普遍，因此该问题特别突出。该物种在低密度（每公顷 0.6-0.8 只鸟）和次大陆范围内（超过 100 万平方千米）对鸟类群落产生影响。一些生态学家建议扑杀是唯一能够及时扭转受威胁的小型林地鸟类数量下降的管理对策。我们在扑杀计划之前和之后的 12 个月内监测了嘈杂矿工的数量，发现从周围景观的立即重新殖民化抵消了扑杀的影响。我们假设这是由于真空效应造成的；即在处理斑块周围更边缘栖息地居住的鸟类会在扑杀后移动到空缺的领地。与对照点相比，在扑杀后期间，处理点的嘈杂矿工的平均数量下降了 22%，而对照点的数量增加了 4%。然而，所有地点的数量仍然是公布的生态影响阈值的三到五倍。投资回报率分析表明，扑杀工作与嘈杂矿工数量的减少之间没有关系。我们得出的结论是，在高度改造的研究景观中，在斑块尺度上扑杀并不能有效地降低嘈杂矿工的数量，使其达到不太可能影响受威胁林地鸟类的水平，尽管估计成本比另一种潜在的管理对策——重新造林低 18 倍。我们的研究强调了在更广泛地应用本能上吸引人但不一定在生态上有效的管理对策之前，建立经验证据的重要性。
