Collaborative Research LTREB Renewal: Tropical rain forest ecosystem responses to climate forcings

热带雨林如何应对气温上升和空气中二氧化碳水平的上升，对全球气候变化和生物多样性保护具有重大影响。在过去的50年里，大气中二氧化碳的年度增加受到陆地热带地区储存的碳量变化的强烈影响，在较温暖的年份，森林排放的热带二氧化碳更多。全球变暖在整个热带地区一直很迅速，而且还在加剧，未来五年可能会创下新的纪录。尽管热带雨林在全球具有重要意义，但很少有实地数据来评估这些森林对气候变化的敏感性。这个项目的研究将再延长五年，这是对热带雨林生产力和动态及其与气候关系的最长研究。这项研究位于哥斯达黎加拉塞尔瓦的古老低地雨林中，在一个旨在进行景观尺度测量的地块网络中。这些测量自1997年以来一直在进行，并将再提供五年的森林碳储量年度实地测量，以及森林对气候变化的反应情况。该项目以前的研究表明，气温升高和干旱胁迫对森林生产力有很强的负面影响，而大气二氧化碳增加对森林生产力的积极影响相对较小。进一步的测量将使研究人员能够在二氧化碳含量更高的更温暖的植物上解决有关热带雨林未来的重要和悬而未决的问题。该项目的更广泛的科学影响包括广泛的研究、培训和开发独特的长期数据集。已经有数十名本科生、研究生和博士后参加了这次活动。该项目制作了近100份同行评议的出版物和论文，并提供了激发其他相关研究所需的数据集。今后五年，项目网站将继续发展，成为全球完全开放获取所有项目数据的主要工具。此外，研究人员将继续与教育和非政府组织开展合作，鼓励在更广泛的公众环境中使用项目数据。

How tropical rain forests respond to rising temperatures and carbon dioxide levels in the air has major implications for global climate change and biodiversity conservation. Over the last 50 years, annual increases in atmospheric carbon dioxide have been strongly affected by changes in the amount of carbon stored in the land tropics, with greater tropical carbon dioxide emitted from the forest in warmer years. Warming has been rapid across the tropics and is intensifying, and the next five year period is likely to bring new records. In spite of the global importance of tropical rain forests, there are few field data to assess the sensitivity of these forests to changing climate. The research in this project will extend for a further five years the longest running study of tropical rain forest productivity and dynamics and their relation to climate. The research is located in old-growth lowland rain forest at La Selva, Costa Rica, in a network of plots designed for making measurements at the landscape scale. The measurements are continuous since 1997 and will provide a further five years of annual field measurements of carbon storage in the forests, and of how the forests are responding to changing climate. Previous research in this project has shown strong negative effects of increased temperature and drought stress, while positive effects of increases in atmospheric carbon dioxide on forest productivity are by comparison very small. Further measurements will enable researchers to address important and unanswered questions about the future of tropical rain forests on a warmer plant with higher levels of carbon dioxide.The broader scientific impacts of this project include extensive research training and development of unique long-term datasets. Already dozens of undergraduates, graduate students and post-docs have participated. The project has produced almost 100 peer reviewed publications and theses and has provided the datasets needed to stimulate other related research. The next five years will bring continued development of the project website as a principal tool for completely open global access to all of the project data. In addition, the researchers will continue to develop collaborations with educational and non-governmental organizations to encourage use of project data in broader general public settings.