Ledru Marie-Pierre auteur aut IRD Jeske-Pieruschka V. auteur aut IRD Bremond L. auteur aut IRD Develle A. L. auteur aut IRD Sabatier P. auteur aut IRD Martins E. S. P. R. auteur aut IRD de Freitas M. R. D. auteur aut IRD Fontenele D. P. auteur aut IRD Arnaud F. auteur aut IRD Favier C. auteur aut IRD Barroso F. R. G. auteur aut IRD Araujo F. S. auteur aut IRD text journalArticle eng text/pdf born digital access The northeastern region of Brazil is the most densely populated and biodiverse semi-arid regions of the planet. Effects of the natural climate variability and colonization on the landscape have been described since the beginning of the 16th century but little is known about their effects on natural resources. Climate projections predict temperatures above 40 degrees C and an increase in the number and duration of droughts at the end of the 21st century with strong societal impacts. Here, we analyze the influence of public policies, human activities and natural climate variability on the environment over the last 60 years. Our study is based on sedimentological and environmental reconstructions from two sediment cores collected in two dam lakes on the river Acarau in the State of Ceara. Multiproxy analyses of both cores (inorganic geochemistry, pollen, charcoal, remote sensing) at an annual resolution showed that 1) at interannual scale composition and distribution of the dry forest (known as Caatinga) were not affected by the alternance of drought and high moisture episodes; 2) at decadal scale human activities such as agriculture were reflected by changes in vegetation cover and fishery by progressive changes in lake trophic status; 3) public policies were able to promote changes in the landscape e.g., land colonization with the regression of the dry forest and irrigation plan able to amplify the deforestation and change the floristic composition. Thanks to paleo-science approach, our environmental diagnosis should help future decision-making and provide guidelines for preservation of resources and wellbeing of the inhabitants. specialized Caatinga Lake reservoir Sediment Drought Land degradation Human impact BRESIL ZONE SEMIARIDE 082 021 076 020 723 137989 [16 ] 2020 0048-9697 https://www.documentation.ird.fr/hor/fdi:010078074 10.1016/j.scitotenv.2020.137989 0048-9697 [F B010078074] https://www.documentation.ird.fr/hor/fdi:010078074 https://www.documentation.ird.fr/intranet/publi/2020/06/010078074.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2020-07-02 2025-02-24 fdi:010078074 fre