Phosphorus, Carbon, and Nitrogen Dynamics in Perturbed Neotropical Dry Forest

扰动的新热带干燥森林中的磷、碳和氮动态

• 批准号: 9118854
• 负责人: Robert Sanford
• 金额: $ 76.43万
• 依托单位: University of Denver
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-10-15 至 1997-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9118854&HistoricalAwards=false
• 关键词: Phosphorus; Carbon; Nitrogen; Dynamics; Perturbed

Tropical dry forests are the most endangered tropical ecosystem. They are also poorly understood, particularly with regard to ecosystem structure, site productivity, nutrient cycling, and resilience following fire. This study will investigate biogeochemical mechanisms in intact, and cut and burn tropical dry forests at Chamela Biological Station, Mexico. The research will focus on pools, flows and losses of phosphorus, nitrogen and carbon, but with particular emphasis on phosphorus because of the distinctive role of phosphorus as the limiting element for plant growth in this system. The principal investigators hypothesize that: (1) a pattern of pulsed nutrient release occurs in soils under intact forest and that this pattern is substantially altered following fire, (2) soil organic reactions mediated by plant and microbial biological activity are fundamental for maintaining phosphorus availability in this system, (3) deforestation and fire cause substantial, and nearly irreversible net losses of phosphorus, nitrogen, and carbon from the system, and (4) repeated burning and/or very severe fires (high biomass consumption) will result in declining long-term site productivity. The researchers will quantify nutrient dynamics and experimentally manipulate both intact forest and fire severity to examine the mechanisms that control cycling and losses of these elements. Results of these studies will be used to validate and further develop simulation models. These models will be used in synthesis work, to examine long-term patterns of forest productivity, and to estimate the effect of fire caused phosphorus, nitrogen and carbon losses from this system. The principle investigators are well-qualified to do this work and the facilities are excellent.

热带干林是最濒危的热带生态系统。对它们的了解也很少，特别是在生态系统结构、场地生产力、养分循环和火灾后恢复力方面。本研究将在墨西哥Chamela生物站调查完整、砍伐和燃烧的热带干燥森林的生物地球化学机制。研究将集中在磷、氮和碳的库、流和损失上，但特别强调磷，因为磷在这个系统中作为植物生长的限制元素具有独特的作用。主要研究人员假设：(1)完整森林土壤中存在一种脉冲式养分释放模式，这种模式在火灾发生后发生了实质性改变；(2)由植物和微生物生物活性调节的土壤有机反应对维持该系统中磷的有效性至关重要；(3)森林砍伐和火灾造成了大量的、几乎不可逆转的磷、氮、氮的净损失。系统中的碳，以及(4)重复燃烧和/或非常严重的火灾（高生物质消耗）将导致长期场地生产力下降。研究人员将量化营养动态，并通过实验操纵完整森林和火灾严重程度来研究控制这些元素循环和损失的机制。这些研究的结果将用于验证和进一步开发模拟模型。这些模型将用于综合工作，以检查森林生产力的长期模式，并估计该系统中因火灾造成的磷、氮和碳损失的影响。主要调查人员完全有资格做这项工作，设施也很好。