Quilodrán Claudio S, Sandvig Erik M, Aguirre Francisco, de Aguilar Juan Rivero, Barroso Omar, Vásquez Rodrigo A, Rozzi Ricardo
Department of Biology and Biochemistry, University of Fribourg, Fribourg, Switzerland.
Department of Zoology, University of Oxford, OX 1 3PS Oxford, United Kingdom.
Biodivers Conserv. 2022;31(2):613-627. doi: 10.1007/s10531-022-02353-5. Epub 2022 Jan 20.
A natural laboratory is a place supporting the conditions for hypothesis testing under non-anthropogenic settings. Located at the southern end of the Magellanic sub-Antarctic ecoregion in southwestern South America, the Cape Horn Biosphere Reserve (CHBR) has one of the most extreme rainfall gradients in the world. Subject to oceanic climate conditions, it is also characterized by moderate thermal fluctuations throughout the year. This makes it a unique natural laboratory for studying the effects of extreme rainfall variations on forest bird communities. Here, we monitor the bird species richness in the different forest types present in the CHBR. We found that species richness decreased with increasing precipitation, in which an increase of 100 mm in average annual precipitation showed about 1% decrease in species richness. Similar patterns were found among different forest types within the CHBR. These results provide a baseline to investigate the interactions between physical and biotic factors in a subpolar region that climatically contrasts with boreal forests, which is subject to continental climatic conditions. This research highlights the importance of ecological and ornithological long-term studies in the CHBR, which can contribute both to a higher resolution of the heterogeneity of climate changes in different regions of the world, and to orient conservation policies in the Magellanic sub-Antarctic ecoregion in the face of growing development pressures.
自然实验室是一个在非人为环境下支持进行假设检验条件的地方。合恩角生物圈保护区（CHBR）位于南美洲西南部麦哲伦亚南极生态区的南端，拥有世界上最极端的降雨梯度之一。受海洋气候条件影响，其全年的温度波动也较为温和。这使其成为研究极端降雨变化对森林鸟类群落影响的独特自然实验室。在此，我们监测了CHBR中不同森林类型的鸟类物种丰富度。我们发现物种丰富度随着降水量的增加而降低，其中年平均降水量每增加100毫米，物种丰富度约下降1%。在CHBR内的不同森林类型中也发现了类似的模式。这些结果为研究与受大陆气候条件影响的北方森林形成气候对比的亚极地地区物理因素与生物因素之间的相互作用提供了一个基线。这项研究凸显了在CHBR进行生态和鸟类学长期研究的重要性，这既有助于更清晰地解析世界不同地区气候变化的异质性，也有助于在麦哲伦亚南极生态区面临日益增长的发展压力时指导保护政策。
