Past and present biomass consumption by herbivores and fire across productivity gradients in North America
Past and present biomass consumption by herbivores and fire across productivity gradients in North America
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DOI：
10.1088/1748-9326/ad0ad0
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发表时间：
2023-11
影响因子：
6.7
通讯作者：
John A.F. Wendt;D. McWethy;G. Hempson;Jack Brookshire;S. Fuhlendorf
中科院分区：
文献类型：
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作者：
John A.F. Wendt;D. McWethy;G. Hempson;Jack Brookshire;S. Fuhlendorf
食草动物和火是植物生物量的重要消费者，影响全球植被结构，养分循环和生物多样性。由于野生食草动物的损失、牲畜的繁殖和火灾制度的改变，历史上生物量消费模式的改变可能会产生严重的生态后果。我们着手（一）了解消费者的主导地位和流行程度如何响应全新世北美的空间和时间湿度梯度和（二）研究如何在北美过去和现在的消费者主导模式相比，现代撒哈拉以南非洲地区的消费者制度改变较少。我们开发了长期记录的野牛丰度和生物量燃烧在全新世北美大陆中部，并将这些记录的水分供应和植被结构的重建。我们使用这些重建的特点野牛和火灾的流行在相关的水分和植被梯度。我们发现，野牛草食动物占主导地位的生物量消耗在干燥的环境中，而火占主导地位，在潮湿的环境。在北美大陆中部的草食动物和燃烧的历史分布类似于当代撒哈拉以南非洲，这表明干扰反馈和相互作用调节长期的消费者动态。当代北美消费者动态与全新世北美和撒哈拉以南非洲的比较也表明，火灾在曾经常见的地区功能缺失，具有深刻的生态影响。
Herbivores and fire are important consumers of plant biomass that influence vegetation structure, nutrient cycling, and biodiversity globally. Departures from historic biomass consumption patterns due to wild herbivore losses, livestock proliferation, and altered fire regimes can have critical ecological consequences. We set out to (i) understand how consumer dominance and prevalence responded to spatial and temporal moisture gradients in Holocene North America and (ii) examine how past and present consumer dominance patterns in North America compare to less altered consumer regimes of modern Sub-Saharan Africa. We developed long-term records of bison abundance and biomass burning in Holocene midcontinent North America and compared these records to reconstructions of moisture availability and vegetation structure. We used these reconstructions to characterize bison and fire prevalence across associated moisture and vegetation gradients. We found that bison herbivory dominated biomass consumption in dry settings whereas fire dominated in wetter environments. Historical distributions of herbivory and burning in midcontinent North America resemble those of contemporary Sub-Saharan Africa, suggesting disturbance feedbacks and interactions regulate long-term consumer dynamics. Comparisons of consumer dynamics in contemporary North America with Holocene North America and Sub-Saharan Africa also reveal that fire is functionally absent from regions where it was once common, with profound ecological implications.