Power M J, Whitney B S, Mayle F E, Neves D M, de Boer E J, Maclean K S
Natural History Museum of Utah, Department of Geography, University of Utah, UT, USA
Department of Geography, Northumbria University Newcastle, Newcastle-Upon-Tyne, UK.
Philos Trans R Soc Lond B Biol Sci. 2016 Jun 5;371(1696). doi: 10.1098/rstb.2015.0165.
South American seasonally dry tropical forests (SDTFs) are critically endangered, with only a small proportion of their original distribution remaining. This paper presents a 12 000 year reconstruction of climate change, fire and vegetation dynamics in the Bolivian Chiquitano SDTF, based upon pollen and charcoal analysis, to examine the resilience of this ecosystem to drought and fire. Our analysis demonstrates a complex relationship between climate, fire and floristic composition over multi-millennial time scales, and reveals that moisture variability is the dominant control upon community turnover in this ecosystem. Maximum drought during the Early Holocene, consistent with regional drought reconstructions, correlates with a period of significant fire activity between 8000 and 7000 cal yr BP which resulted in a decrease in SDTF diversity. As fire activity declined but severe regional droughts persisted through the Middle Holocene, SDTFs, including Anadenanthera and Astronium, became firmly established in the Bolivian lowlands. The trend of decreasing fire activity during the last two millennia promotes the idea among forest ecologists that SDTFs are threatened by fire. Our analysis shows that the Chiquitano seasonally dry biome has been more resilient to Holocene changes in climate and fire regime than previously assumed, but raises questions over whether this resilience will continue in the future under increased temperatures and drought coupled with a higher frequency anthropogenic fire regime.This article is part of the themed issue 'The interaction of fire and mankind'.
南美洲季节性干燥热带森林（SDTFs）面临极度濒危状况，其原始分布仅剩下一小部分。本文基于花粉和木炭分析，呈现了玻利维亚奇基塔诺季节性干燥热带森林12000年的气候变化、火灾及植被动态重建情况，以研究该生态系统对干旱和火灾的恢复力。我们的分析表明，在数千年的时间尺度上，气候、火灾和植物区系组成之间存在复杂关系，并揭示出湿度变化是该生态系统群落更替的主要控制因素。全新世早期的最大干旱期，与区域干旱重建结果一致，与公元前8000年至7000年期间一段显著的火灾活动期相关，这导致了季节性干燥热带森林多样性的下降。随着火灾活动减少，但严重的区域干旱在全新世中期持续存在，包括南美猴耳环属和星裂榄属在内的季节性干燥热带森林在玻利维亚低地稳固建立。过去两千年间火灾活动减少的趋势，促使森林生态学家们认为季节性干燥热带森林受到火灾威胁。我们的分析表明，奇基塔诺季节性干燥生物群落对全新世气候变化和火灾格局的恢复力比之前设想的更强，但也引发了一个问题，即在气温升高、干旱加剧以及人为火灾频率增加的未来，这种恢复力是否还会持续。本文是主题为“火与人类的相互作用”特刊的一部分。
