Luquillo LTER Program 4: Understanding Change in the Ecosystems of Northeastern Puerto Rico

该卢基略长期生态研究计划（LUQ）的重点是了解在波多黎各的卢基略山脉的热带森林生态系统的长期变化的驱动因素。LUQ将在先前强调自然干扰（飓风、山崩、干旱、洪水）和生态系统反应的基础上，继续研究中海拔Tabonuco森林的生态系统结构和过程，将研究范围扩大到沿着海拔梯度的其他森林类型，并开始调查影响卢基略山脉的区域尺度过程。将采用四种方法：长期实验和测量，不同森林群落之间的比较分析，从森林到城市的梯度分析，以及使用概念和模拟模型的综合，越来越多的证据表明，飓风强度的增加，山区降雨量的减少，以及低地城市化地区气温的上升，可以显著影响卢基略山区的生态系统。在这种情况下，首要的问题是：如何在扰动制度和气候的变化改变地球化学循环，生物结构和生态系统服务？这导致了三个具体的问题，解决LUQ概念框架的关键要素：1）是什么控制碳和营养盐通量的变化，以及这些变化是如何被干扰修改？卢基略山脉的许多过程都表现出明确的季节性和与气候的联系。了解这些关系对于确定生物区系和生物地球化学循环对环境变化的敏感性至关重要。2)沿着卢基略海拔梯度的温度、降雨、光照和风（气候）的变化是否足以解释地球化学过程和生物结构的变化？LUQ建议研究气候的线性和非线性趋势，卢基略山脉的海拔作为生态系统过程和生物分布的驱动因素。通过提高对生物和非生物因素在确定热带山区生物体空间梯度分布中的重要性的认识，科学家们将提高他们理解变化影响的能力。3）土地利用的变化在确定长期生态系统地球化学、生物结构和服务方面有多重要？土地利用和土地覆盖在波多黎各东北部急剧变化，以应对社会经济的变化。LUQ计划研究土地利用和土地覆盖变化对一系列特征的长期影响，包括区域和当地气候、树种组成、河流生态和一个关键的生态系统服务：为人类提供清洁的水。拟议的研究将为热带生态系统和生态系统服务的管理提供一个改进的科学框架。它将通过概念上的进步和对人类干扰和生态系统反应的记录来做到这一点。该项目将继续培养一批青年和少数族裔科学家，他们精通将人口和生态系统方法与环境变化评价联系起来，并将向他们提供可在热带地区或其他地方应用的技能。LUQ开发了一个综合教育计划，涉及六所高中网络的教师和一个基于网络的中学生态教学课程。其他的推广活动旨在提高公众对卢基略山脉的溪流为周围城镇提供的水资源的认识。

The Luquillo Long-Term Ecological Research Program (LUQ) focuses on understanding factors driving long-term change in tropical forest ecosystems in the Luquillo Mountains of Puerto Rico. Building on an earlier emphasis on natural disturbances (hurricanes, landslides, droughts, floods) and ecosystem responses, LUQ will continue studies of ecosystem structure and processes in mid-elevation tabonuco forest, extend research into other forest types along an elevation gradient, and begin investigations of regional-scale processes affecting the Luquillo Mountains. Four approaches will be used: long-term experiments and measurements, comparative analyses among different forest communities, gradient analysis from forest to urban, and synthesis using conceptual and simulation models.Mounting evidence suggests that increasing hurricane intensity, declining rainfall in the mountains, and rising temperature in lowland urbanized areas can significantly affect the ecosystems of the Luquillo Mountains. In this context, the overarching question is: How do changes in disturbance regime and climate alter biogeochemical cycles, biotic structure, and ecosystem services? This leads to three specific questions addressing key elements of the LUQ conceptual framework:1) What controls variation in carbon and nutrient fluxes, and how are these variations modified by disturbance? Many processes in the Luquillo Mountains exhibit well defined seasonality and links to climate. Understanding these relationships is essential for determining the sensitivity of biota and biogeochemical cycling to environmental change. 2) Are changes in temperature, rainfall, light and wind (climate) along the Luquillo elevation gradient sufficient to explain variation in biogeochemical processes and biotic structure? LUQ proposes to study linear and non-linear trends in climate with elevation in the Luquillo Mountains as drivers of ecosystem processes and the distribution of organisms. By improving understanding of the importance of biotic and abiotic factors in determining the distribution of organisms over spatial gradients in tropical mountains, scientists will increase their ability to understand the effects of change.3) How important are changes in land-use in determining long-term ecosystembiogeochemistry, biotic structure, and services? Land-use and land-cover are changingdramatically in northeastern Puerto Rico in response to socioeconomic changes. LUQ proposes to examine the long-term effects of land-use and land-cover change on a range of features, including regional and local climate, tree species composition, stream ecology, and a key ecosystem service: the delivery of clean water for humans.The proposed research will provide an improved scientific framework for the management of tropical ecosystems and ecosystem services. It will do so both through conceptual advances and documentation of human disturbance and ecosystem response. The project will continue to produce a cadre of young and minority scientists who are versed in linking population and ecosystem approaches to evaluating environmental change, and will provide them with skills that can be applied in tropical regions or elsewhere. LUQ has developed a comprehensive education program involving teachers at a network of six high schools and a web-based middle school curriculum for teaching ecology. Additional outreach activities are directed at improving the general public's appreciation of the water resources provided to surrounding towns by streams draining the Luquillo Mountains.