Seed‐dispersal mode and habitat connectivity underpin variation in carbon stocking between Brazilian biomes

In tropical forests, about 60%–80% of woody plant species depend on animal–plant interactions for dispersal. The dependence on animal species for dispersal makes this interaction very fragile in the face of anthropogenic changes in land use. Disrupting seed‐dispersal processes, principally zoochoric dispersal, could significantly alter the long‐term carbon storage potential of tropical forests. An important question is how landscape structure changes tree carbon stocks in different types of tropical vegetation and how variation is mediated by the dispersal mode of animal (zoochoric) or abiotic (non‐zoochoric) seeds. We focused on tree plots at 126 sites in Brazil spanning four types of forest and savanna vegetation, and calculated carbon stored in zoochoric, non‐zoochoric, and large frugivore‐dispersed species. Our results showed that carbon stocks in zoochoric species and non‐zoochoric species differ significantly among vegetation types, with rainforests having higher stocks in zoochoric species and deciduous seasonally dry tropical forests having higher values in non‐zoochoric species. A greater area of native vegetation promotes higher proportions of carbon stocks dispersed by large frugivore species, whereas a higher mean shape index reduces this proportion. Synthesis. This study highlights that seed‐dispersal type underpins the variation in carbon stocks between vegetation types and that the maintenance of habitat of large dispersers and connectivity are key for retaining carbon stocks in zoochoric species, particularly in rainforest and cerrado sensu stricto. Resumo Nas florestas tropicais, cerca de 60 a 80% das espécies de plantas lenhosas dependem da interações planta‐animal para dispersão de suas sementes. Essa dependência torna a interação muito frágil face às mudanças antropogênicas no uso da terra. A interrupção dos processos de dispersão de sementes, principalmente a dispersão zoocórica, pode alterar significativamente o potencial de armazenamento de carbono a longo prazo das florestas tropicais. Uma questão importante é como a estrutura da paisagem altera os estoques de carbono das árvores em diferentes tipos de vegetação tropical e como a variação é mediada pelo modo de dispersão de sementes dispersas por animais (zoocóricas) ou abióticas (não zoocóricas). Nós nos concentramos em parcelas de árvores em 126 locais no Brasil, abrangendo quatro tipos de vegetação florestal e de savana, e calculamos o carbono armazenado em espécies zoocóricas, n