Fire-Induced Floristic and Structural Degradation Across a Vegetation Gradient in the Southern Amazon

first_pagesettingsOrder Article Reprints Open AccessArticle Fire-Induced Floristic and Structural Degradation Across a Vegetation Gradient in the Southern Amazon by Loriene Gomes da Rocha 1,2,Ben Hur Marimon Junior 1,2,*ORCID,Amauri de Castro Barradas 1,2,Marco Antônio Camillo de Carvalho 1ORCID,Célia Regina Araújo Soares 1,Beatriz Schwantes Marimon 2,Gabriel H. P. de Mello Ribeiro 3ORCID,Edmar A. de Oliveira 2,Fernando Elias 4ORCID,Carmino Emidio Júnior 1,Dennis Rodrigues da Silva 1ORCID,Marcos Leandro Garcia 1,Jesulino Alves da Rocha Filho 1,Marcelo Zortea 1,2,Edmar Santos Moreira 1,Samiele Camargo de Oliveira Domingues 1,2,Eraldo A. T. Matricardi 5ORCID,David Galbraith 2,6,Ted R. Feldpausch 2,7ORCID,Imma Oliveras 2,8 andOliver L. Phillips 6ORCIDremove Hide full author list 1 Graduate Program in Biodiversity and Amazonian Agroecosystems, Campus of Alta Floresta, UNEMAT–State University of Mato Grosso, Alta Floresta CEP 78.580-000, Brazil 2 LABEV–Laboratory of Plant Ecology, Campus of Nova Xavantina, UNEMAT–State University of Mato Grosso, Nova Xavantina CEP 78.690-000, Brazil 3 Faculdade de Engenharia Florestal, UFMT–Federal University of Mato Grosso, Campus of Cuiabá, Cuiabá CEP 78.060-900, Brazil 4 Departament of Biology, Graduate Program in Forest Sciences, UFRA-Universidade Federal Rural da Amazônia, Campus of Capitão Poço, Capitão Poço CEP 68.650-000, Brazil 5 Department of Forestry, UnB–University of Brasilia, Brasilia CEP 70.910-900, Brazil 6 School of Geography, University of Leeds, Leeds LS2 9JT, UK 7 Geography, Faculty of Environment, Science and Economy, University of Exeter, Exeter EX4 4QJ, UK 8 AMAP (Botanique et Modélisation de l’Architecture des Plantes et des Végétations), University Montpellier, CIRAD, CNRS, INRA, IRD, 34090 Montpellier, France * Author to whom correspondence should be addressed. Forests 2025, 16(8), 1218; https://doi.org/10.3390/f16081218 (registering DOI) Submission received: 24 April 2025 / Revised: 30 June 2025 / Accepted: 22 July 2025 / Published: 24 July 2025 (This article belongs to the Special Issue Tropical Forests, Water Cycle, Global Cycles of Greenhouse Gases and Climate Change) Downloadkeyboard_arrow_down Browse Figures Versions Notes Abstract Climate change and landscape fragmentation have made fires the primary drivers of forest degradation in Southern Amazonia. Understanding their impacts is crucial for informing public conservation policies. In this study, we assessed the effects of repeated fires on trees with a diameter ≥10 cm across three distinct vegetation types in this threatened region: Amazonian successional forest (SF), transitional forest (TF), and ombrophilous forest (OF). Two anthropogenic fires affected all three vegetation types in consecutive years. We hypothesized that SF would be the least impacted due to its more open structure and the presence of fire-adapted savanna (Cerrado) species. As expected, SF experienced the lowest tree mortality rate (9.1%). However, both TF and OF were heavily affected, with mortality rates of 28.0% and 29.7%, respectively. Despite SF’s apparent fire resilience, all vegetation types experienced a significant net loss of species and individuals. These results indicate a fire-induced degradation stage in both TF and OF, characterized by reduced species diversity and structural integrity. Our findings suggest that recurrent fires may trigger irreversible vegetation shifts and broader ecosystem tipping points across the Amazonian frontier.