Environmental changes during the last millennium based on multi-proxy palaeoecological records in a savanna-forest mosaic from the northernmost Brazilian Amazon region

Anais da Academia Brasileira de Ciências

Maria Ecilene N.s. Meneses¹  Marcondes L. Costa¹  Dirk Enters¹  Hermann Behling¹ 

关键词: fire frequency;    late Holocene;    Roraima state-Brazil;    vegetation dynamic;    frequência do fogo;    Holoceno tardio;    Roraima-Brasil;    dinâmica da vegetação;   

DOI  :  10.1590/0001-3765201520130074

来源: SciELO

【 摘 要 】

ABSTRACTThe environmental changes and the dynamics of the savanna-forest mosaic, over the last 1050 years, have been reconstructed by pollen, charcoal, radiocarbon dating mineralogical and geochemical analyses of sediment cores taken from three different Mauritia flexuosapalm swamps in the northernmost part of the Brazilian Amazon region (northern state of Roraima). Studies on the relationship between the modern pollen rain and the regional vegetation provide additional information for the interpretation of the fossil pollen records. The fossil pollen assemblages and geochemical results indicate relatively wet climatic conditions throughout the recorded period. Despite these moist conditions, fires were frequent and are one of the reasons for the dominance of a grassy savanna instead of forest expansion in the study area. Considering the generally wet climatic conditions, these fires were most likely caused by human activities. Even today, fires hinder forest expansion into savanna areas. Sandy hydromorphic soils may also act as an edaphic control to maintain the current sharp boundary between forest and savanna ecosystems.

【 授权许可】

CC BY   
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