Collaborative Research: Linking models to data to investigate patterns and process in savannas

协作研究：将模型与数据联系起来以研究稀树草原的模式和过程

• 批准号: 0950347
• 负责人: Brian Beckage
• 金额: $ 35.5万
• 依托单位: University of Vermont & State Agricultural College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0950347&HistoricalAwards=false
• 关键词: Collaborative; Research; Linking; models; data

Savannas are ecological communities comprised of scattered trees in a grassland matrix. The mechanisms leading to the coexistence of grasses and trees and the persistence of savanna communities over long time periods are unclear. Opposing ecological theories have predicted either equilibrium savanna communities that result from niche partitioning or non-equilibrium savannas that result from repeated disturbances such as fire. This project will consider an alternative model to explain the structure of savannas, in which stability results from feedbacks between fire disturbance and vegetation. It will test the hypothesis that flammable savanna plants result in more frequent or intense fires and that these fires, in turn, promote the growth and establishment of savanna vegetation. Such positive feedbacks between savanna vegetation and fire could maintain the density of trees between the extremes of treeless prairies and the closed canopy of forests. The project will further explore whether less frequent, periodic disturbances such as hurricanes could have interactive effects with fire that could initiate vegetation-fire feedbacks and rescue savannas from a forest state. The underlying assumptions and predictions of a disturbance-feedback model will be tested using empirical and experimental data collected from sites that have been studied for the past 30 years in southern Florida, southwestern Georgia, and eastern Louisiana, and that broadly represent pine savannas in the southeastern United States. Demographic and spatial patterns predicted by a disturbance-feedback model will be compared to field observations and experimental data to ascertain the validity of the model.This alternative model of savanna dynamics will contribute to a general understanding of the processes that structure savannas across a wide range of environments worldwide, and will facilitate predictions of savanna responses to disturbances such as climate warming and landscape fragmentation. Understanding savanna responses to perturbations is of broad significance as savannas comprise an eighth of the global land surface, provide essential ecological services, and are important reservoirs of biodiversity. Results from this project will also be broadly applicable to ecological restoration and management of ecosystems across the United States. This project will support a postdoctoral scholar and provide research training for graduate and undergraduate students, and Girl Scouts at a camp near the study site in Louisiana.

稀树草原是由散布在草原基质中的树木组成的生态群落。 导致草和树的共存和草原群落的持久性在很长一段时间内的机制尚不清楚。 相反的生态学理论预测，要么平衡稀树草原群落的结果，生态位分割或非平衡稀树草原的结果，反复干扰，如火灾。 本项目将考虑另一种模式来解释热带稀树草原的结构，其中稳定性是由火灾干扰和植被之间的反馈造成的。 它将检验易燃的稀树草原植物导致更频繁或更强烈的火灾，而这些火灾反过来又促进稀树草原植被的生长和建立的假设。 稀树草原植被和火灾之间的这种正反馈可以将树木密度维持在无树草原和封闭森林树冠的极端之间。 该项目将进一步探讨飓风等不太频繁的周期性扰动是否会与火灾产生相互作用，从而引发植被-火灾反馈，并将热带稀树草原从森林状态中拯救出来。 干扰反馈模型的基本假设和预测将使用经验和实验数据进行测试，这些数据收集自过去30年来在佛罗里达南部、格鲁吉亚西南部和路易斯安那州东部进行研究的地点，这些地点广泛代表了美国东南部的松树稀树草原。 人口和空间格局预测的干扰反馈模型将进行比较，实地观察和实验数据，以确定模型的有效性，这一替代模型的稀树草原动态将有助于结构稀树草原在世界范围内的各种环境的过程的一般理解，并将促进稀树草原对干扰，如气候变暖和景观破碎化的预测。 了解稀树草原对扰动的反应具有广泛的意义，因为稀树草原占全球陆地表面的八分之一，提供基本的生态服务，是生物多样性的重要储存库。 该项目的成果也将广泛适用于美国各地生态系统的生态恢复和管理。 该项目将支持一名博士后学者，并为研究生和本科生以及路易斯安那州研究地点附近的一个营地的女童子军提供研究培训。