The Amazon is widely recognized for its biological diversity and the presence of distinct vegetation types, such as terra firme rainforests, seasonally flooded várzea and igapó forests, as well as more open ecosystems like campinaranas and Amazonian savannas. However, this region faces severe anthropogenic threats, particularly the conversion of natural habitats into agricultural areas and pastures, resulting in biodiversity decline. Among the most threatened ecosystems are the Amazonian savannas, characterized by their high ecological heterogeneity.In the state of Amapá, one of the most preserved territories in the Brazilian Amazon, savannas occupy over 7% of its total area, but approximately 160,000 hectares have already been converted into eucalyptus plantations. These plantations can impact vertebrate communities in various ways, being neutral or even beneficial for some species. Among the groups most sensitive to these changes are non-flying small mammals, which respond to landscape alterations due to their diverse behaviors, making them ideal indicators for investigating the ecological effects of these transformations.he objective of this study is to understand the influence of vegetation and landscape structure on the composition, abundance, and diversity of non-flying small mammals in a landscape comprising eucalyptus plantations, savannas, and forests in the central region of Amapá, Eastern Amazon.To achieve this, field sampling of non-flying small mammals was conducted using live-capture traps (Sherman and cage traps) and pitfall traps, distributed across 50 randomly placed transects within the studied phytophysiognomies (eucalyptus plantations, savanna, and forests). To analyze the influence of vegetation structure, the following variables were assessed: canopy cover (%), understory density (%), litter cover, and height (%). To evaluate the effects of landscape configuration, we examined seven landscape variables:Proportion of habitats within a 200 m buffer around the transect, Area of the patch where the transect was located (ha),Amount of edge within the buffer (m),Amount of roads within the buffer (m),Nearest distance to forest patches (m),Nearest distance to savanna patches (m),Nearest distance to water (m).To determine whether there were differences in the richness and abundance of non-flying small mammals across different landscapes and vegetation structures, Generalized Linear Models (GLMs) were used. To explore the importance of environmental factors in species composition, Distance-based Redundancy Analysis (dbRDA) was applied. For beta diversity analysis, its components of richness difference and species replacement were partitioned using Jaccard dissimilarity matrices to calculate the Local Contribution to Beta Diversity (LCBD). To test the influence of environmental variables on local contributions to beta diversity and its partitions, GLMs were applied. All analyses were conducted using R software.Results revealed 170 individuals of non-flying small mammals distributed across 20 species. The highest abundance was recorded in forests, followed by eucalyptus plantations and savanna. Environmental variables influenced the abundance and richness of rodents and marsupials. Marsupial abundance was positively related to understory density and distance to savanna but negatively related to the proportion of savanna within the buffer and distance to water. Rodent richness and abundance were positively associated with forests and negatively with savanna.Beta diversity was mainly driven by species replacement, indicating species turnover between locations rather than differences in the total species numbers per site. Most predictors showed an accelerating effect on beta diversity, increasing differences between sampling points. The diversity of small mammals in Amazonian environments was strongly influenced by habitat heterogeneity, which was a key factor shaping non-flying small mammal communities in a given area. Eucalyptus plantations with understory vegetation and surrounding native savanna and forest vegetation can sustain part of the local diversity.While savannas exhibited lower diversity compared to other phytophysiognomies, they harbored more balanced communities with species specialized in these habitats. The spatial heterogeneity of the landscape, in terms of habitat composition and arrangement, shapes community dynamics, directly influencing species turnover, occupancy, and persistence rates. Maintaining areas with different characteristics within the same landscape allows for the coexistence of a greater number of species with varying ecological requirements.