DISSERTATION RESEARCH: The alteration of landscape nutrient flows by human-induced increases in generalist omnivores

所有生物体都需要营养物质，如氮、钾和磷，而这些营养物质在生境之间的移动可能会从根本上改变它们对植物生长的可用性，并最终改变依赖这些植物的动物的可获得性。动物可能是营养物质在太空中移动的重要途径。人类通过消灭一些物种和引入其他物种改变了这些营养物质的流动，这可能会对生态功能产生许多直接和间接的影响。野猪是一种最早由西班牙人引入新大陆的物种，现在分布广泛，数量丰富，是一个典型的物种，它可能会对栖息地之间的营养流动产生巨大影响。位于佛罗里达州墨西哥湾沿岸的下苏万尼国家野生动物保护区正在进行一项关于野猪对生态系统养分流动的影响的详细研究。这一景观由森林覆盖的岛屿组成，岛屿交错在盐沼中。这些猪将这些岛屿作为避难所，它们对这些地区的密集使用导致了岛屿森林栖息地粪便物质的高度沉积。调查显示，与大陆森林土壤相比，岛屿森林土壤的营养水平更高，这似乎对当地植物群落产生了相当大的影响。已经建立了围栏，以确定野猪是否真的是这些避难所地区营养物质增加的原因，并检查它们对植物的影响。为了确定沉积营养物质的来源，正在通过分析粪便和骨骼样本来确定猪的饮食。对粪便中DNA的遗传分析将有助于估计种群规模，并结合种群对营养物质沉积的影响，将允许“每头猪”表达野猪对营养物质流动的影响。野猪和野猪遍布全球，在美国东南部往往非常丰富。保护区和公园的管理人员认为它们具有很强的破坏性，但过去的研究没有量化它们对营养物质流动的影响程度，尽管它们显然可以深刻地改变当地的生态过程。这项研究的结果应该具有广泛的适用性，为许多受干扰的生态系统的管理提供基本知识。该项目还丰富了科学教育。本科生将参与实地考察和实验室分析。将鼓励学生开发自己的相关项目。一名学生将检查周期性食物短缺的印记，以及牙齿、牙釉质和骨骼中记录的疾病。这名学生最终将把研究结果应用于人类的考古遗迹。参与该项目提供的教育体验的一个不同寻常的方面是，学生将与避难所的广泛非学术用户进行互动，例如通过准备教育材料和幻灯片演示文稿，通过下苏万尼之友和国家野生动物保护区系统等组织向公众提供。

All organisms require nutrients, such as nitrogen, potassium, and phosphorus, and movements of these nutrients among habitats may fundamentally alter their availability for plant growth, and ultimately for the animals dependent upon these plants. Animals can be important avenues of nutrient movement across space. Humans have altered these nutrient flows, both by eliminating some species, and by introducing others which can lead to many direct and indirect impacts on ecological function. Feral swine - a species which was first introduced to the New World by the Spaniards and are now widespread and abundant - is a classic example of a species that can potentially have large impacts upon nutrient flows among habitats. A detailed study of impacts of feral pigs upon ecosystem nutrient flows is being undertaken in the Lower Suwannee National Wildlife Refuge, located on the Gulf Coast of Florida. The landscape consists of forested islands interlaced in salt marsh. The pigs use the islands as refuges, and their intense use of these areas has led to high deposition of fecal material in the island forest habitats. Surveys revealed higher nutrient levels in the island forest soil compared to mainland forest soil, and there appear to be considerable impacts upon local plant communities. Exclosures have been set up to determine whether feral hogs are indeed responsible for increased nutrients in these refuges areas, and to examine their impact on the plants. To determine the source of the deposited nutrients, the diet of the hogs is being determined through analysis of fecal and bone samples. Genetic analysis of DNA in the feces will permit an estimation of population size and, combined with the effect the population has on nutrient deposition, will allow a 'per hog' expression of the impact of feral hogs on the nutrient flows. Feral and wild pigs are found globally and are often very abundant in the southeastern U.S.A. Refuge and park managers consider them to be very destructive, but past work has not quantified the magnitude of their impacts on nutrient flows, even though it is clear that they can profoundly alter local ecological processes. The results of this study should have wide applicability, providing basic knowledge that can assist management of many disturbed ecosystems. The project also enriches science education. Undergraduates will be involved in both in the fieldwork and in laboratory analysis. Students will be encouraged to develop their own related projects. One student will examine the imprint of periodic food scarcity as well as disease recorded in tooth enamel and bones. The student will eventually apply the results to the archaeological remains of human populations. One unusual aspect of the educational experience provided by involvement with this project is that students will be interacting with a wide range of non-academic users of the refuge, for instance by the preparation of educational materials and Powerpoint presentations made available to the general public via organizations like the Friends of Lower Suwannee and the National Wildlife Refuge system.