Catastrophic Disturbance in a Tropical Rain Forest - Impact of the Riparian Zone on Nutrient Export

1989年9月17日至18日，飓风雨果几乎完全 波多黎各的卢基略实验森林被砍伐的部分 瑞可 飓风森林砍伐与其他森林砍伐有很大不同。 在热带森林中研究的干扰（伐木， 刀耕火种农业），主要是因为 大量的活生物质立即进入表面垃圾 车厢 没有足够的数据来预测这些垃圾 输入将影响或影响养分动态在 这片热带森林的河岸地带。 麦克道尔，鲍登和史密斯博士已经在附近取样- 地表地下水和溪流水在这片森林中的两个地点 自1988年8月以来。 他们的工作强调营养和水 通过河岸带的通量，并评估相对 微生物与维管植物控制养分重要性 通过这个接口。 这个新项目将研究森林砍伐的影响 飓风雨果对河岸带的能力， 调节营养物质从陆地到水生的运输 生态系统 研究人员假设， 在调节氮素损失方面起着至关重要的作用 在这场灾难性的骚乱之后。 他们特别 确定两个主要假设：（1）森林砍伐与 飓风雨果将导致河流出口增加， 氮从比斯利流域，和2）的大小 河流中的氮输出将显著减少， 氮的保持和转化。 为了检验这些假设， 飓风雨果之前和之后的信息将被比较 在两个地点，一个被干扰，一个未被干扰。 从事这项研究的科学家经验丰富， 具有河岸管理经验的高效研究人员 在热带森林的过程。 该计划得到了 优秀的机构设施。

On September 17-18, 1989, Hurricane Hugo almost completely deforested portions of the Luquillo Experimental Forest in Puerto Rico. Hurricane deforestation differs substantially from other disturbances that have been studied in tropical forests (logging, slash and burn agriculture) principally in that an enormous amount of live biomass instantly enters the surface litter compartment. Insufficient data exist to predict how this litter input will affect or be affected by nutrient dynamics in the riparian zone of this tropical forest. Drs. McDowell, Bowden and Smith have been sampling near- surface ground water and stream water at two sites in this forest since August 1988. Their work emphasizes the nutrient and water flux through the riparian zone and assesses the relative importance of microbial versus vascular plant control of nutrient flux through this interface. This new project will examine the impact of deforestation caused by Hurricane Hugo on the ability of riparian zones to regulate transport of nutrients from terrestrial to aquatic ecosystems. The investigators hypothesize that the riparian zone plays a crucial role in regulating losses of nitrogen following this catastrophic disturbance. They specifically identify two major hypotheses: 1) deforestation associated with Hurricane Hugo will result in increased fluvial export of nitrogen from the Bisley watershed, and 2) the magnitude of nitrogen export in stream water will be lessened significantly by nitrogen retention and transformation. To test these hypotheses, information from before and after Hurricane Hugo will be compared at two sites, one disturbed and one undisturbed. The scientists engaged in this research are experienced, productive researchers who have previous experience with riparian processes in tropical forests. The program is supported by excellent institutional facilities.