Wild Rice Population Dynamics and Nutrient Cycles

野生稻种群动态和养分循环

• 批准号: 0211691
• 负责人: John Pastor
• 金额: $ 54.31万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-15 至 2007-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0211691&HistoricalAwards=false
• 关键词: Wild; Rice; Population; Dynamics; Nutrient

Populations of plants and animals typically undergo regular oscillations or boom-and-bust cycles in nature. Ecologists have long been interested in the causes of these oscillations. Ecological theory predicts that any delay in a population will cause it to oscillate. Most of the processes that have been proposed as causes of delays are purely population processes, such as delays in birth rate. But if the recycling of limiting nutrients between decaying plant material (litter) and live plants is delayed, this could also cause a population to oscillate.Wild rice is an interesting wetland plant species whose populations have long been known to oscillate. Wild rice is an annual plant and so the population must meet all its nutrients requirements for growth from the release of nutrients in decaying litter from previous years. Almost all the nutrients wild rice needs for growth are taken up in a brief window in spring-early summer of the year. But litter from the previous year decomposes so slowly that it does not even begin to release nutrients until at least the end of summer or not even until the second year of decay. We hypothesize that this delay in the recycling of nutrients through decaying litter causes wild rice populations to oscillate.Besides being ecologically interesting, wild rice is an important staple food for members of Minnesota's Ojibway (Chippewa) tribe. Wild rice harvesting is a defining feature of Ojibway society. Ojibway culture includes legends of wild rice spiritual ceremonies conducted during harvest time. Wild rice approaches sacred food status and band members identify wild rice as a symbol of what it means to be Ojibway. The Ojibway tribe manages over a dozen wild rice lakes in northeastern Minnesota for wild rice production in as natural a manner as possible. Therefore, what causes oscillations in wild rice production is of interest, culturally and scientifically, to tribal members as well as to a wider scientific community. This research will involve close collaboration with members of the Fond du Lac band of Ojibway.The effect of delays in nutrient release on wild rice population dynamics will be tested by the following three-pronged approach: (1) making long-term observations of wild rice productivity, seed production, and nutrient availability in sediments in a series of wild rice lakes; (2) manipulating litter, nutrient inputs, and seed vs. seedling establishment in large mesocosms (stock tanks) and measuring total productivity and nutrient uptake, mean plant weight and nutrient uptake, seedling emergence, and nutrient availability; and (3) constructing and testing a computer model of wild rice nutrient uptake, productivity, litter decay, and seed production and emergence.Students will be recruited from the tribal community college to assist in this work. This project will assist tribal biologists in addressing problems of natural resource management of significance to Ojibway values and show tribal students the potentials of a career in the environmental sciences. The tribe is anticipating that the results of this study will provide critical information for its development of nutrient criteria specifically for wild rice waters, and for improving management decisions from a better understanding of nutrient cycling in wild rice ecosystems.

植物和动物的种群通常会在自然界进行定期振荡或繁荣的周期。生态学家长期以来一直对这些振荡的原因感兴趣。生态理论预测，人口的任何延迟都会导致其振荡。提出的大多数作为延迟原因的过程都是纯粹的人口过程，例如出生率的延迟。但是，如果延迟腐烂的植物材料（垃圾）和活植物之间的限制营养物质的回收，这也可能导致种群振荡。野大米是一种有趣的湿地植物，其种群长期以来一直在振荡。野生大米是一年一度的植物，因此人口必须满足其所有养分需求，从而在过去几年的腐烂垃圾中释放营养物质。在今年春天的夏季，在短暂的窗户中，几乎所有野生米的野生水稻都需要满足。但是上一年的垃圾分解得如此之缓慢，以至于至少直到夏季结束或直到衰减的第二年才开始释放营养。我们假设，通过腐烂的垃圾通过腐烂的营养物质回收的延迟会导致野生水稻的振荡。Besides在生态上很有趣，野生大米是明尼苏达州Ojibway（Chippewa）部落成员的重要主食。野生水稻收获是Ojibway Society的一个定义特征。 Ojibway文化包括在收获期间进行的野生稻精神仪式的传说。野生水稻接近神圣的食物状况，乐队成员将野生米定为象征着成为Ojibway的意义。奥吉布韦部落在明尼苏达州东北部管理了十几个野生水稻湖泊，以尽可能自然的方式生产野生水稻。因此，在文化和科学上，对部落成员以及更广泛的科学界引起的野生水稻生产的振荡是感兴趣的。这项研究将涉及与Ojibway的Fond du Lac乐队成员的密切合作。养分释放中延迟对野生水稻种群动态的影响将通过以下三个普通方法进行测试：（1）长期观察一系列野生水稻湖泊中野生水稻生产率，种子生产力，种子生产和养分的养分； （2）操纵垃圾，养分输入和种子与幼苗建立在大型中罐（储存罐）中，并测量总生产率和养分吸收，平均植物重量和养分摄取，幼苗出现，幼苗的出现和营养利用率； （3）构建和测试野生水稻营养摄取，生产力，垃圾衰减以及种子生产和出现的计算机模型。将从部落社区学院招募学生，以协助这项工作。该项目将帮助部落生物学家解决对奥吉韦价值观重要的自然资源管理问题，并向部落学生展示环境科学职业的潜力。该部落预测，这项研究的结果将为其针对野生水域的营养标准的发展提供关键信息，并从对野生水稻生态系统中的营养循环中更好地了解管理决策。