Palaeobiology, Canadian Museum of Nature, Ottawa, ON, Canada.
Biology, Carleton University, Ottawa, ON, Canada.
Nat Commun. 2022 Jul 8;13(1):3940. doi: 10.1038/s41467-022-31595-8.
Biotic homogenization-increasing similarity of species composition among ecological communities-has been linked to anthropogenic processes operating over the last century. Fossil evidence, however, suggests that humans have had impacts on ecosystems for millennia. We quantify biotic homogenization of North American mammalian assemblages during the late Pleistocene through Holocene (30,000 ybp to recent), a timespan encompassing increased evidence of humans on the landscape (20,000-14,000 ybp). From 10,000 ybp to recent, assemblages became significantly more homogenous (>100% increase in Jaccard similarity), a pattern that cannot be explained by changes in fossil record sampling. Homogenization was most pronounced among mammals larger than 1 kg and occurred in two phases. The first followed the megafaunal extinction at ~10,000 ybp. The second, more rapid phase began during human population growth and early agricultural intensification (2,000-1,000 ybp). We show that North American ecosystems were homogenizing for millennia, extending human impacts back ~10,000 years.
生物同质化——生态群落中物种组成的相似性增加——与上个世纪以来的人为过程有关。然而，化石证据表明，人类对生态系统的影响已经持续了数千年。我们量化了更新世晚期到全新世（约 30000 年前到现在）北美哺乳动物组合的生物同质化，这一时间跨度包括人类在景观上的影响证据增加（约 20000-14000 年前）。从约 10000 年前到现在，组合变得更加同质化（杰卡德相似性增加超过 100%），这种模式不能用化石记录采样的变化来解释。同质化在大于 1 公斤的哺乳动物中最为明显，并且发生在两个阶段。第一阶段紧随约 10000 年前的巨型动物灭绝。第二阶段，更快的阶段始于人类人口增长和早期农业集约化（约 2000-1000 年前）。我们表明，北美生态系统已经同质化了数千年，将人类的影响追溯到约 10000 年前。
