COLLABORATIVE RESEARCH: The Nature of Fire-Vegetation Relationships in Tropical Savanna-Forest Mosaics

热带稀树草原的火曾经被视为破坏性的，现在被视为维持物种多样性的动植物群落的关键。事实上，科学家现在认识到，尽管将火排除在具有破坏性的地方(热带雨林)很重要，但在有益的地方(热带草原)推广火也同样重要。适当的火灾管理是保护生物多样性和维持人民生计的关键。然而，人们对如何(或是否)同时完成防火和防火工作知之甚少。该项目的首要目标是调和稀树草原火灾的需要和保护森林免受野火破坏的需要。利用玻利维亚大草原和森林的实地和实验室研究，该项目将为生活在大草原/森林基质中的人们如何以有益于生态的方式使用火奠定科学基础。此外，该项目将为博士生和博士后学者提供进行国际实地研究的机会，并为本科生提供在美国进行实验室分析的机会。为了促进国际教育交流，将向来自美国和玻利维亚的学生提供热带生态学和植物野外方法的短期课程。将组织一次研究研讨会和讲习班，以进一步解决将有益的火灾管理纳入热带稀树草原和森林保护倡议的挑战。这项研究将提供热带稀树草原-森林镶嵌中替代稳定状态理论的首次实地测试，在这种镶嵌中，火-植被反馈可以与土壤和植物光合作用类型的影响隔离。在上个世纪的大部分时间里，在气候可以支持封闭树冠森林的地区，生态学家将热带稀树草原的存在归因于土壤条件或人为砍伐森林。这些想法正在被一种新的范式所取代，在这种范式中，稀树草原和森林被建模为替代的稳定状态，由植物群落和火之间的反馈来维持。这项研究将跨越玻利维亚稀树草原-森林边界进行，将使用植被和土壤采样、田间实验、遥感、植物微化石鉴定和年代测定以及功能特征测量来了解植物群落和火之间的当代、古生态和进化关系。预计结果将证明，在缺乏外部驱动因素(如伐木)的情况下，草类的持续殖民权衡促进了稀树草原的易燃性，同时限制了稀树草原向森林的扩展。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Once viewed as destructive, fire in tropical savannas is now seen as critical to the maintenance of species-diverse plant and animal communities. Indeed, scientists now recognize that while it is important to exclude fire from places where it is destructive (tropical forests), it is equally important to promote fire in places where it is beneficial (savannas). Appropriate fire management is key to conserving biodiversity and sustaining the livelihoods of people. However, little is known about how (or if) fire-promotion and fire-protection can be accomplished simultaneously. The overarching goal of this project is to reconcile the need for savanna fires with the need to protect forests from damaging wildfire. Using field and laboratory studies in savannas and forests of Bolivia, this project will establish the scientific basis for how people living in a savanna/forest matrix can use fire in an ecologically beneficial manner. Additionally, this project will provide opportunities for a doctoral student and a postdoctoral scholar to conduct international field research, and for undergraduate students to conduct laboratory analyses in the USA. To foster international educational exchange, a short course in tropical ecology and botanical field methods will be offered to students from the USA and Bolivia. A research symposium and workshop will be organized to further address the challenges of incorporating beneficial fire management into savanna and forest conservation initiatives.This research will provide the first-ever field-based test of alternative stable state theory in a tropical savanna-forest mosaic where fire-vegetation feedbacks can be isolated from the effects of soils and plant photosynthetic type. For most of the past century, in regions where the climate can support closed-canopy forests, ecologists attributed the existence of tropical savannas to edaphic conditions or human-caused deforestation. Such ideas are being replaced by a new paradigm in which savannas and forests are modelled as alternative stable states, maintained by feedbacks between plant communities and fire. This research, to be conducted across savanna-forest boundaries in Bolivia, will use vegetation and soil sampling, field experiments, remote sensing, plant microfossil identification and dating, and functional trait measurements to understand the contemporary, paleoecological, and evolutionary relationships between plant communities and fire. Results are expected to demonstrate that in the absence of external drivers, such as logging, a persistence-colonization trade-off in grasses promotes savanna flammability while constraining savanna expansion into forests.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.