Centre for Biodiversity and Restoration Ecology, School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand.
California State University, Sacramento 6000 J Street, Sacramento, CA, 95819, U.S.A.
Conserv Biol. 2021 Feb;35(1):35-49. doi: 10.1111/cobi.13456. Epub 2020 Mar 23.
Over the past 1000 years New Zealand has lost 40-50% of its bird species, and over half of these extinctions are attributable to predation by introduced mammals. Populations of many extant forest bird species continue to be depredated by mammals, especially rats, possums, and mustelids. The management history of New Zealand's forests over the past 50 years presents a unique opportunity because a varied program of mammalian predator control has created a replicated management experiment. We conducted a meta-analysis of population-level responses of forest birds to different levels of mammal control recorded across New Zealand. We collected data from 32 uniquely treated sites and 20 extant bird species representing a total of 247 population responses to 3 intensities of invasive mammal control (zero, low, and high). The treatments varied from eradication of invasive mammals via ground-based techniques to periodic suppression of mammals via aerially sown toxin. We modeled population-level responses of birds according to key life history attributes to determine the biological processes that influence species' responses to management. Large endemic species, such as the Kaka (Nestor meridionalis) and New Zealand Pigeon (Hemiphaga novaeseelandiae), responded positively at the population level to mammal control in 61 of 77 cases for species ≥20 g compared with 31 positive responses from 78 cases for species <20 g. The Fantail (Rhipidura fuliginosa) and Grey Warbler (Gerygone igata), both shallow endemic species, and 4 nonendemic species (Blackbird [Turdus merula], Chaffinch [Fringilla coelebs], Dunnock [Prunella modularis], and Silvereye [Zosterops lateralis]) that arrived in New Zealand in the last 200 years tended to have slight negative or neutral responses to mammal control (59 of 77 cases). Our results suggest that large, deeply endemic forest birds, especially cavity nesters, are most at risk of further decline in the absence of mammal control and, conversely suggest that 6 species apparently tolerate the presence of invasive mammals and may be sensitive to competition from larger endemic birds.
在过去的 1000 年中，新西兰已经失去了 40-50%的鸟类物种，其中超过一半的灭绝归因于引入哺乳动物的捕食。许多现存的森林鸟类物种的数量仍然受到哺乳动物的捕食，尤其是老鼠、负鼠和鼬科动物。在过去 50 年中，新西兰森林的管理历史提供了一个独特的机会，因为各种哺乳动物捕食者控制计划创造了一个重复的管理实验。我们对新西兰各地记录的不同程度的哺乳动物控制对森林鸟类种群水平反应进行了荟萃分析。我们从 32 个独特处理的地点和 20 种现存鸟类中收集了数据，这些鸟类代表了对 3 种入侵哺乳动物控制强度（零、低和高）的 247 个种群反应。这些处理从地面技术根除入侵哺乳动物到通过空中播撒毒素定期抑制哺乳动物不等。我们根据关键生活史属性对鸟类的种群水平反应进行了建模，以确定影响物种对管理反应的生物学过程。大型特有物种，如卡卡（Nestor meridionalis）和新西兰鸽子（Hemiphaga novaeseelandiae），在 77 个物种≥20 克的案例中，有 61 个对哺乳动物控制的种群水平反应呈阳性，而在 78 个物种<20 克的案例中，有 31 个呈阳性反应。扇尾鹟（Rhipidura fuliginosa）和灰莺（Gerygone igata），都是浅层特有物种，以及 4 种非特有物种（黑鸟[Turdus merula]、燕雀[Fringilla coelebs]、雀鹀[Prunella modularis]和银眼[Zosterops lateralis]），它们在过去 200 年中抵达新西兰，对哺乳动物控制的反应往往略微负面或中性（77 个案例中有 59 个）。我们的研究结果表明，大型、深度特有森林鸟类，特别是洞穴筑巢鸟类，在没有哺乳动物控制的情况下，最有可能进一步减少，相反，6 种物种显然耐受入侵哺乳动物的存在，并且可能对大型特有鸟类的竞争敏感。
