Wildlife Conservation Society, Global Conservation Program, Bronx, New York, USA.
Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Glob Chang Biol. 2022 Feb;28(3):918-935. doi: 10.1111/gcb.15962. Epub 2021 Nov 13.
Rapid climate change is impacting biodiversity, ecosystem function, and human well-being. Though the magnitude and trajectory of climate change are becoming clearer, our understanding of how these changes reshape terrestrial life zones-distinct biogeographic units characterized by biotemperature, precipitation, and aridity representing broad-scale ecosystem types-is limited. To address this gap, we used high-resolution historical climatologies and climate projections to determine the global distribution of historical (1901-1920), contemporary (1979-2013), and future (2061-2080) life zones. Comparing the historical and contemporary distributions shows that changes from one life zone to another during the 20th century impacted 27 million km (18.3% of land), with consequences for social and ecological systems. Such changes took place in all biomes, most notably in Boreal Forests, Temperate Coniferous Forests, and Tropical Coniferous Forests. Comparing the contemporary and future life zone distributions shows the pace of life zone changes accelerating rapidly in the 21st century. By 2070, such changes would impact an additional 62 million km (42.6% of land) under "business-as-usual" (RCP8.5) emissions scenarios. Accelerated rates of change are observed in hundreds of ecoregions across all biomes except Tropical Coniferous Forests. While only 30 ecoregions (3.5%) had over half of their areas change to a different life zone during the 20th century, by 2070 this number is projected to climb to 111 ecoregions (13.1%) under RCP4.5 and 281 ecoregions (33.2%) under RCP8.5. We identified weak correlations between life zone change and threatened vertebrate richness, levels of vertebrate endemism, cropland extent, and human population densities within ecoregions, illustrating the ubiquitous risks of life zone changes to diverse social-ecological systems. The accelerated pace of life zone changes will increasingly challenge adaptive conservation and sustainable development strategies that incorrectly assume current ecological patterns and livelihood provisioning systems will persist.
快速的气候变化正在影响生物多样性、生态系统功能和人类福祉。尽管气候变化的幅度和轨迹变得更加清晰，但我们对这些变化如何重塑陆地生命带（以生物温度、降水和干旱为特征的独特生物地理单元，代表广泛的生态系统类型）的理解是有限的。为了解决这一差距，我们使用高分辨率的历史气候数据和气候预测来确定历史（1901-1920 年）、当代（1979-2013 年）和未来（2061-2080 年）生命带的全球分布。比较历史和当代的分布表明，在 20 世纪，从一个生命带转变为另一个生命带的变化影响了 2700 万平方千米（占陆地的 18.3%），这对社会和生态系统产生了影响。这种变化发生在所有生物群系中，最显著的是北方森林、温带针叶林和热带针叶林。比较当代和未来的生命带分布表明，生命带变化的速度在 21 世纪迅速加快。到 2070 年，在“照常营业”（RCP8.5）排放情景下，这种变化将影响另外 6200 万平方千米（占陆地的 42.6%）的土地。在所有生物群系中，除了热带针叶林之外，数百个生态区都观察到了快速的变化速度。虽然在 20 世纪，只有 30 个生态区（3.5%）有一半以上的面积转变为不同的生命带，但到 2070 年，根据 RCP4.5，这一数字预计将攀升至 111 个生态区（13.1%），而根据 RCP8.5，这一数字将攀升至 281 个生态区（33.2%）。我们发现，生命带变化与受威胁的脊椎动物丰富度、脊椎动物特有性水平、耕地面积和生态区的人口密度之间存在弱相关性，这说明了生命带变化对各种社会生态系统的普遍风险。生命带变化的加速步伐将越来越挑战适应性保护和可持续发展战略，这些战略错误地假设当前的生态模式和生计供应系统将持续下去。
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