Biome stability in South America over the last 30 kyr: Inferences from long-term vegetation dynamics and habitat modelling
Biome stability in South America over the last 30 kyr: Inferences from long-term vegetation dynamics and habitat modelling
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DOI：
10.1111/geb.12694
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发表时间：
2018-03-01
影响因子：
6.4
通讯作者：
Carnaval, Ana Carolina
中科院分区：
文献类型：
--
作者：
Costa, Gabriel C.;Hampe, Arndt;Carnaval, Ana Carolina
目的：目的是研究过去的生物群落稳定性，植被动态和生物多样性模式之间的联系。地点：南美洲。时间段：过去30，000年。研究的主要类群：Plants.Methods：我们将南美洲分为主要生物群落根据其占主导地位的植物功能群（草，树木和灌木）和运行随机森林（RF）分类与当前气候的数据。然后，我们拟合了算法，以预测每1,000年的生物群落分布，追溯到21,000年BP，并通过计算气候变化预测将网格单元从一个生物群落转移到另一个生物群落的次数来估计生物群落的稳定性。我们比较了我们的基于模型的稳定性地图与经验估计，从选定的花粉记录覆盖过去30 kyr的植被变化，物种组成的变化和植被响应的时滞。结果：我们发现我们的栖息地稳定性地图和区域植被动态之间有很强的相关性。根据气候变化期间森林分布的变化方式，出现了四种情景。每个场景都涉及到生物群落稳定性和多样性的特定区域特征，使我们能够制定具体的预测生物多样性的分类，遗传和功能组件可能会受到现代气候变化的影响。主要结论：我们验证的生物群落稳定性地图提供了重要的基线信息，为研究过去气候对南美洲生物多样性的影响。通过专门关注具有明显相关性的气候变化（即，它提供了一个新的视角，补充了以前的数据集，并使科学家能够在地方、区域和大陆尺度上探索新的问题和假设。
Aim: The aim was to examine the links between past biome stability, vegetation dynamics and biodiversity patterns.Location: South America.Time period: Last 30,000 years.Major taxa studied: Plants.Methods: We classified South America into major biomes according to their dominant plant functional groups (grasses, trees and shrubs) and ran a random forest (RF) classification with data on current climate. We then fitted the algorithm to predict biome distributions for every 1,000 years back to 21,000 yr BP and estimated biome stability by counting how many times a change in climate was predicted to shift a grid cell from one biome to another. We compared our model-based stability map with empirical estimates from selected pollen records covering the past 30 kyr in terms of vegetation shifts, changes in species composition and time-lag of vegetation responses.Results: We found a strong correlation between our habitat stability map and regional vegetation dynamics. Four scenarios emerged according to the way forest distribution shifted during a climate change. Each scenario related to specific regional features of biome stability and diversity, allowing us to formulate specific predictions on how taxonomic, genetic and functional components of biodiversity might be impacted by modern climate change.Main conclusions: Our validated map of biome stability provides important baseline information for studying the impacts of past climate on biodiversity in South America. By focusing exclusively on climatic changes of manifested relevance (i.e., those resulting in significant habitat changes), it provides a novel perspective that complements previous datasets and allows scientists to explore new questions and hypotheses at the local, regional and continental scales.