Plant diversity conservation in highly deforested landscapes of the Brazilian Atlantic Forest

•Matrices influence plant diversity of inferior stratum, being higher in pastureland.•Time since abandonment positively influences plant diversity of the superior stratum.•Beta diversity is high at the studied highly deforested landscapes in Atlantic Forest.•In sugarcane matrix, richness and composition were explained by landscape structure.•In pastureland matrix, plant diversity was more related to landscape dynamic metrics. [Display omitted] Different types of matrices can perform different disturbance regimes over remnant forests, which can ultimately affect plant diversity. To address these issues, we studied 60 plots in forest remnants embedded within sugarcane plantations and pasturelands in the Atlantic Forest of Southeastern Brazil. Our objectives were to evaluate general patterns of plant diversity and to assess the influence of landscape structure and dynamics on plant richness and diversity. We recorded 297 species in two strata. (DBH superior stratum ≥ 4.8 cm > inferior stratum). Overall, diversity of the inferior stratum was higher in pastureland forest remnants than in sugarcane matrices. In the superior stratum, time since abandonment represented a greater influence. Considering the partition of diversity, more than 40% of total diversity was due to the alpha component alone in all cases, but it was significantly lower than expected. Beta components among forest remnants, landscapes and matrices were higher than expected for both strata, whether together or separately. Habitat heterogeneity showed a higher contribution to the total floristic diversity, but among remnants this contribution was even more significant. Forest remnants in pasturelands had a more dynamic land use history and parameters of landscape dynamics were more related to plant diversity. For remnants in the sugarcane matrices, species richness and composition were explained by landscape structure. Our results highlight that there is an important plant community diffused in the forest remnants of human-modified landscapes. Therefore, conserving the majority of remnants and restoring degraded ones must be a key conservation strategy.