Theory and application of medium-term successional dynamics in secondary tropical forest

越来越需要将热带地区大片退化的生境恢复为森林，以保护生物多样性，减轻气候变化的影响（通过碳固存），减少表土的侵蚀和流失，并为人类提供生计，但人们对热带森林恢复战略在建立最初几年之后的效果知之甚少。这项长期实验旨在解决有关热带森林恢复的两个关键问题。 首先，该研究将天然林恢复与两种不同的森林恢复方法（低强度和高强度方法）进行比较，以评估人类干预程度如何影响热带森林恢复的速度。 其次，该研究评估了恢复的网站附近的重要性，残余的森林补丁，可以作为一个来源的殖民植物和动物。 这项研究的结果将为土地管理者和决策者提供重要指导，指导他们如何最有效地投资有限的资源，以改善全球正在进行的数百万公顷热带森林恢复的成果。这项研究将为研究生和本科生提供培训，新的探究式学习计划将积极吸引高中生参与研究。十多年前，在哥斯达黎加南部100平方公里的地区建立了13个实验点，每个点周围都有一系列森林覆盖。每个站点有三个实验处理：1。没有植树和自然恢复; 2.种植三种大小的树岛（低强度）;以及3.在整个地块上种植树木（高密度）。研究人员将收集有关指标的数据，以评估森林演替的下一阶段，包括测量土壤养分、当地小气候、种子传播、树木生长以及森林幼苗的建立和存活。 此外，合作的科学家将利用这些地块研究森林恢复的其他方面，如昆虫群落动态、鸟类和蝙蝠行为。这些数据将用于解决关于中期森林恢复以及恢复模式如何随时间变化的几个问题，包括：恢复干预措施对场地内和场地间生物多样性的影响;对初始条件的操纵在多大程度上导致参考森林的演替轨迹趋同或发散;以及地方与森林恢复的相对重要性。

There is a growing need to restore extensive areas of degraded habitat in tropical areas to forest in order to conserve biodiversity, mitigate the impacts of climate change (through carbon sequestration), reduce erosion and loss of topsoil, and provide for human livelihoods, yet little is known about how well tropical forest restoration strategies work beyond the first few years of establishment. This long-term experiment aims to address two key questions about tropical forest recovery. First, the research compares natural forest recovery to two different forest restoration approaches (a low and high intensity approach) to assess how the degree of human intervention affects the rate of tropical forest recovery. Second, the study evaluates the importance of the proximity of restored sites to remnant forest patches, which can serve as a source for colonizing plants and animals. Results of this study will provide critical guidance to land managers and policy makers on how to most effectively invest limited resources to improve the outcomes of the millions of hectares of tropical forest restoration being undertaken globally. The study will provide training for graduate and undergraduate students, and new inquiry-based learning program will actively engage high school students in the research. Over a decade ago, 13 experimental sites were established over a 100 square kilometer area in southern Costa Rica, each site with a range of surrounding forest cover. Each site has three experimental treatments: 1. no tree planting and natural recovery; 2. planting tree islands of three sizes (low intensity); and 3. planting the entire plot with trees (high intensity). Researchers will collect data on metrics to assess the next phase of forest succession, including measuring soil nutrients, local microclimate, seed dispersal, tree growth, and the establishment and survival of forest seedlings. In addition, plots will be used by collaborating scientists to study other facets of forest recovery such as insect community dynamics, and bird and bat behavior. The data will be used to address several questions about mid-stage forest recovery and how the pattern of recovery can change over time including: the effect of restoration interventions on within- and across-site biodiversity; the degree to which manipulations of initial conditions result in convergent or divergent successional trajectories from reference forest; and the relative importance of local- versus landscape-scale processes on forest recovery.