DISSERTATION RESEARCH: Landscape Development Affects Ecosystem Processes in Tropical Forests.

本研究旨在确定热带森林树木养分供应的变异性及其原因。虽然大多数热带森林被认为营养贫乏，但有证据表明，侵蚀可以通过使新的、营养丰富的岩石暴露于风化而增加营养的供应。在夏威夷，这种影响很明显，斜坡上的树木通常比未被侵蚀的表面上的树木要大得多，养分浓度也更高。因此，考艾岛上一小片热带森林的生育力差异与整个夏威夷群岛未受侵蚀的地表一样大。尽管这些结果对了解夏威夷森林很重要，但尚不清楚夏威夷对大陆森林有多好。为了澄清这个问题，我们正在对哥斯达黎加低地热带森林的营养变化进行量化。比较这些系统将揭示夏威夷模式对热带大陆的适用性，以及热带景观中营养变化的程度。答案对科学家和决策者都有广泛的意义，因为养分供应的空间变化影响物种分布、碳储存和农业的可持续性。

This research is to determine the variability of nutrient supply to trees in tropical forests, and its causes. Although most tropical forests are considered nutrient poor, there is evidence that erosion can increase the supply of nutrients by exposing new, nutrient rich rock to weathering. In Hawaii, this effect can be pronounced and trees on slopes are often much bigger, with higher nutrient concentrations, than trees on uneroded surfaces. As a result, there is as much variation in fertility across a small section of tropical forest on the old island of Kauai as there is on uneroded surfaces across the entire Hawaiian Islands. Despite the importance of these results for understanding Hawaiian forests, it is not clear how good a proxy Hawaii is for continental forests. To clarify this question, we are quantifying nutrient variability across a lowland tropical forest in Costa Rica. Comparing these systems will shed light both on the applicability of the Hawaiian model to the continental tropics and the extent of nutrient variability across tropical landscapes. The answer has broad implications for both scientists and policy makers, because spatial variation in nutrient supply affects species distributions, carbon storage, and the sustainability of agriculture.