Fernanda Moreira Gianasi

Abstract Recent evidence indicates that Brazilian forests are shifting from persistent carbon sinks to emerging carbon sources, with important implications for the global climate. To investigate this trend, we analyse long-term census data from 49 forest sites spanning southeast and southern Brazil, including tropical and subtropical forests.

1 Introduction Floodplain forests are important ecosystems, located at the interface between water and land (Wohl 2021). They are shaped by water and sediment dynamics and provide a unique setting for high biodiversity and productivity (Tockner and Stanford 2002; Zhang et al. 2023). However, these ecosystems are threatened by anthropogenic alterations of flow regimes, for example, due to dam construction (de Resende et al. 2019), land use change (Rajib et al.

1 INTRODUCTION Floodplain forests are important ecotones between stream channels and upland areas. Floodplain forests have a high biodiversity (Ward et al., 1999) and provide many ecosystem services (Tockner & Stanford, 2002), such as the mitigation of floods (Barth & Döll, 2016), carbon sequestration (Shupe et al., 2022), and maintenance of water quality (Hopkins et al., 2018).