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

热带干旱森林是最濒危的热带生态系统。 人们对这些原则也知之甚少，特别是关于 生态系统结构、立地生产力、养分循环， 火灾后的恢复力 本研究将调查 在完整的，切割和燃烧的热带干旱中的地球化学机制 Chamela生物站，墨西哥。 这项研究将 重点关注磷、氮和 碳，但特别强调磷，因为 磷作为植物生长限制元素的独特作用 在这个系统中成长。 主要研究人员假设 （1）土壤养分释放呈脉冲式 在完整的森林下，这种模式被大大改变了， 火灾后，（2）植物介导的土壤有机反应， 微生物生物活性是维持 该系统中磷的有效性，（3）森林砍伐和火灾 造成巨大的，几乎不可逆转的净损失， 磷、氮和碳，以及（4）重复 燃烧和/或非常严重的火灾（高生物量消耗）将 导致长期生产力下降。 研究人员 将量化养分动态，并通过实验来操纵 完整的森林和火灾的严重程度，以检查的机制， 控制这些元素的循环和损耗。 结果进行 研究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 火灾造成的磷，氮和碳的损失， 这系统. 主要的调查人员都很有资格做 这个工作和设施都很好。

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.