Collaborative Research: Ecological legacy effects of megacarcasses in African savanna ecosystems

合作研究：非洲稀树草原生态系统中巨型动物的生态遗产效应

• 批准号: 2128094
• 负责人: Nathan Lemoine
• 金额: $ 46万
• 依托单位: Marquette University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-10-01 至 2024-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2128094&HistoricalAwards=false
• 关键词: Collaborative; Research; Ecological; legacy; effects

Large animals such as elephants and rhinoceros, called ‘megafauna’ for their extreme size, have outsized impacts on the ecosystems they live in. They engineer their environments by knocking down trees and grazing grasses to create large lawns, helping to form habitats that facilitate other animals. But, there is little research that addresses the impact that the carcasses of these megafauna, or ‘megacarcasses’, have on ecosystems after they die. Their carcasses represent huge sources of nutrients that have a long-lasting ecological legacy on the areas of ecosystems where their carcasses occur. For example, African elephants are the largest land animals, but almost nothing is known about how the nutrients from their massive carcasses (up to 6,000 kg) affect savanna ecosystems. This award asks the main question: How do elephant megacarcasses affect the ecology of African savannas? The work will address how these megacarcasses affect nutrient cycling in the soil by microbes, plant primary production and species diversity, and herbivory by vertebrate herbivores, such as zebra and giraffe, and invertebrate herbivores, such as grasshoppers. This research will support the mentoring of 1 postdoctoral scholar, graduate and undergraduate students in ecology as well as science communication and outreach. The main broader impact will be the production of a scientific documentary, The Legacy of Megaherbivores, which will ‘follow’ the life and death of an elephant in the African savanna, that will put the life cycle of these elephants into broader ecological context, understanding how they impact ecosystems and the current implications for ecosystems facing their disappearance. To address the overarching question, the award will use elephant carcasses of different ages (up to 15+ years old) in Kruger National Park (KNP), South Africa. Combining soil (physical, chemical and biological properties), plant (productivity and diversity), and herbivore (vertebrate and invertebrate) surveys at 50 megacarcass sites along with greenhouse experiments, the award will assess how nutrient pulses from elephant carcasses drive integrated responses of ecosystem processes. Importantly, the elephant megacarcasses are distributed across gradients of rainfall (375-700 mm) and soil fertility (less-fertile sandy, granitic soils vs. more-fertile clayey, basaltic soils) in KNP. These gradients of rainfall and soil nutrients provide a robust experimental framework for testing how the abiotic environment impacts the ecosystem-level legacy effects of terrestrial megacarcasses. Finally, by combining the data from the field on the effects of megacarcasses on ecosystem processes with a database of elephant population across KNP, the researchers will use ecological modeling to show how the distribution of megacarcasses generates variability in ecosystem processes across the savanna landscape as elephants naturally die over time. This study will represent the first examination of the ecological legacies of megacarcasses on terrestrial ecosystems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

大象和犀牛等大型动物因其体型巨大而被称为“巨型动物群”，对它们所生活的生态系统有着巨大的影响。它们通过砍倒树木和放牧草来创造大片草坪来改造自己的环境，帮助形成栖息地，从而促进其他动物的生存。但是，很少有研究探讨这些巨型动物的尸体或“巨型动物尸体”在死亡后对生态系统的影响，它们的尸体代表着巨大的营养来源。例如，非洲象是最大的陆地动物，但人们对其巨大尸体（重达 6,000 公斤）中的营养物质如何影响稀树草原生态系统几乎一无所知。该奖项提出了一个主要问题：大象巨型尸体如何影响非洲稀树草原的生态？这项工作将解决这些巨型大象尸体如何影响微生物、植物初级生产和物种在土壤中的养分循环。这项研究将支持 1 名博士后学者、研究生和本科生在生态学以及更广泛的科学传播和推广方面的指导。影响将是一部科学纪录片《巨型食草动物的遗产》的制作，该纪录片将“追踪”非洲大草原上大象的生与死，这将把为了解决这个首要问题，该奖项将使用克鲁格不同年龄（最多 15 岁）的大象尸体。南非国家公园 (KNP)，结合对 50 个巨型动物遗址的土壤（物理、化学和生物特性）、植物（生产力和多样性）和食草动物（脊椎动物和无脊椎动物）进行调查。温室实验中，该奖项将评估大象尸体的营养脉冲如何驱动生态系统过程的综合反应。重要的是，大象巨型尸体分布在降雨量（375-700毫米）和土壤肥力梯度（肥力较低的沙质、花岗岩土壤与肥沃的土壤）之间。 KNP 中的这些降雨和土壤养分梯度提供了一个强大的实验框架，用于测试非生物环境如何影响陆地生态系统水平的遗留影响。最后，通过将巨型尸体对生态系统过程影响的实地数据与 KNP 大象种群数据库相结合，研究人员将使用生态模型来展示巨型尸体的分布如何在整个稀树草原景观中产生生态系统过程的变异性。随着时间的推移，大象会自然死亡。这项研究将是对陆地生态系统中巨型大象的生态遗产的首次研究。该奖项是美国国家科学基金会的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准。