LTER: Long-Term Ecological Research in the Luquillo Experimental Forest 3

LTER：卢科伊洛实验森林的长期生态研究 3

• 批准号: 0218039
• 负责人: Nicholas Brokaw
• 金额: --
• 依托单位: University of Puerto Rico-Rio Piedras
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-12-01 至 2009-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0218039&HistoricalAwards=false
• 关键词: LTER; Long; Term; Ecological; Research

The Luquillo Experimental Forest LTER program (LUQ) focuses on the long-term dynamics of tropical forest ecosystems characterized by large-scale, infrequent disturbance, rapid processing of organic material, and high habitat and species diversity. Research by LUQ has stimulated a new appreciation of the significance of large-scale disturbances in tropical forested ecosystems and the key role of the biota in shaping the response to these events. Hurricanes occurring one and 10 years after the LTER program began permitted scientists to capitalize upon landscape-scale natural experiments which are followed closely. Among the most important findings from these natural experiments is that detrital dynamics plays a central role in forest recovery by influencing carbon and nutrient storage and flow. The central theme proposed is that disturbance, through its effects on detrital dynamics, is a dominant ecosystem driver at LUQ. Pulses of detritus shift the flow of energy within the food web, modify the availability and distribution of nutrients, and feed back on the composition and productivity of plant and animal communities. Rapid processing of detritus distinguishes LUQ from other forested LTER sites, where decomposition takes 2-20 times as long. A combination of long-term measurements, field experiments, simulation modeling, and cross-site comparisons are proposed to address five questions: (1) How do climatic factors, litter quality, and detritivore diversity regulate decomposition of detrital pulses? (2) How do terrestrial and aquatic food webs differ in response to detrital pulses? (3) What is the effect of disturbance frequency on nutrient cycling, plant community composition, and the accumulation of soil organic matter? (4) To what degree is the export of carbon and nutrients from watersheds a result of soil characteristics that are affected by detrital dynamics? (5) How do elevationally related changes in climate impact plant and detritivore communities, and how do these feed back on the quantity and quality of litter inputs and decomposition? The research will be conducted in two spatial contexts. In mid-elevation tabonuco forest, LUQ will continue long-term measurements of ecosystem response to hurricanes, landslides, and anthropogenic disturbance. An experiment will be initiated to mimic increased frequency of hurricanes to investigate the effect of increased detrital inputs on nutrient cycling, community composition, and organic matter accumulation, along with. Manipulations of key groups of invertebrates to gain a better understanding of similarities in detrital processing between aquatic and terrestrial food webs. New plots will be established to examine the effect of elevationally related changes in climate, plant communities, and decomposers on detrital processing. Manipulative experiments will compare the relative importance of abiotic and biotic controls on decomposition in terrestrial and aquatic habitats. Long-term measurements of hydrological and nutrient fluxes in watersheds will relate soil characteristics to stream nutrient and organic matter losses and provide information to gauge the effects of future disturbances. Simulation models of key population, community, biogeochemical, and landscape processes provide null-model predictions to inform these new observations and experiments.

卢基略实验森林LTER计划（LUQ）的重点是热带森林生态系统的长期动态，其特点是大规模，不频繁的干扰，快速处理有机物质，高栖息地和物种多样性。LUQ的研究促使人们重新认识到热带森林生态系统大规模扰动的重要性以及生物群在形成对这些事件的反应方面的关键作用。在LTER计划开始一年和十年后发生的飓风使科学家能够利用密切关注的大规模自然实验。这些自然实验的最重要发现之一是，碎屑动态通过影响碳和养分的储存和流动，在森林恢复中发挥着核心作用。 提出的中心主题是，干扰，通过其对碎屑动力学的影响，是一个占主导地位的生态系统驱动器在LUQ。碎屑的脉动改变了食物网中的能量流动，改变了营养物质的可用性和分布，并反馈到植物和动物群落的组成和生产力上。碎屑的快速处理将LUQ与其他森林LTER站点区分开来，在其他森林LTER站点，分解需要2-20倍的时间。 长期测量，田间试验，模拟建模和跨站点比较相结合，提出了解决五个问题：（1）如何气候因素，凋落物质量和食草动物多样性调节碎屑脉冲的分解？(2)陆生和水生食物网对碎屑脉冲的反应有何不同？(3)干扰频率对养分循环、植物群落组成和土壤有机质积累有何影响？(4)从流域输出的碳和养分在多大程度上是受碎屑动态影响的土壤特性的结果？(5)海拔相关的气候变化如何影响植物和食草动物群落，以及这些如何反馈到凋落物输入和分解的数量和质量？ 研究将在两个空间背景下进行。在中海拔禁忌森林，LUQ将继续长期测量生态系统对飓风，山体滑坡和人为干扰的反应。将启动一项模拟飓风频率增加的实验，以调查增加碎屑输入对养分循环、群落组成和有机质积累的影响，同时沿着。操纵无脊椎动物的关键群体，以更好地了解水生和陆生食物网之间碎屑处理的相似性。将建立新的地块，以研究海拔相关的气候变化，植物群落和分解碎屑处理的影响。操纵实验将比较非生物和生物控制在陆地和水生生境中对分解的相对重要性。 长期测量流域的水文和养分通量，将把土壤特性与溪流养分和有机物损失联系起来，并提供信息，以衡量未来扰动的影响。模拟模型的关键人口，社区，地球化学和景观过程提供零模型预测，为这些新的观察和实验。