Revista Brasileira de Geografia Física v.16, n.6 (2023) 3006-3019. 3006 Melo Júnior, J. C. F., Tietz, A. L., Cruz, A. C., Reis, B. G. Schroeder, G. R., Almeida, L.S., Travassos, R. C. T, Cabral, R. D. C, Kampmann, W. Structural differences in herbaceous communities on edge and interior atlantic forest in South Brazil João Carlos Ferreira de Melo Júnior¹,²; Allison Leandro Tietz¹, Andressa da Cruz¹; Bruna Geovana Reis¹; Gabriel da Rosa Schroeder¹; Lucas Souza de Almeida¹; Renata Cristine Temóteo Travassos¹ Rodrigo Dümes Chaves Cabral¹ & Walter Kampmann¹ 1Laboratory of Morphology and Plant Ecology, Universidade da Região de Joinville Santa Catarina, Brazil 2Corresponding author: joao.melo@univille.br Artigo recebido em 07/08/2023 e aceito em 06/12/2023 ABSTRACT The Atlantic Forest is recognized worldwide as hotspots due to its megadiversity. It is estimated that in this biome there are about 20 thousand plant species, which represents 35% of the species existing in Brazil. This study aimed to evaluate whether there are differences between the floristic and structural diversity of the herbaceous component in an edge and interior region of the southern Brazilian Atlantic Forest. The study was developed in a forest fragment (13 hectars) located in the state of Santa Catarina, south Brazil. The edge of the fragment is characterized by an area up to 10-15m wide, covered massively by herbaceous-subshrub vegetation and rare arboreal individuals. The interior is discontinuously shaded by the arboreal and shrub component contained in the upper strata of the forest. The phytosociological survey used the plot method. 100 plots of 1 m² were established, 50 on the edge of the forest fragment and 50 plots inside it. obtained in linear transects of 20m. The phytosociological parameters studied for both areas were absolute frequency (AF), relative frequency (RF), absolute coverage (AC) and relative coverage (RC). Through the treatment and analysis of these data, the importance value index (IVI) of each species was obtained. At the edge of the forest fragment, 18 families and 34 species were identified. Of the 34 species found, 31 are angiosperms (24 dicots and 7 monocots) and 3 are monilophytes. All species are native to the Brazilian flora, with the exception of Centella asiatica and 2 lycophytes. In the interior, 14 species were found, being represented by 10 families. All species in the interior were angiosperms (4 dicots and 8 monocots) and 2 monilophytes. All species are native to the Brazilian flora and have herbaceous habit. The herbaceous community in the interior is different from the herbaceous community at the forest edge. The initial hypothesis of the work was confirmed, since none of the species present at the edge of the forest occurs in the interior of the forest. Keywords: atlantic forest, rain forest, herbaceous community, phytosociology, biodiversity conservation Diferenças estruturais em comunidades herbáceas na transição entre a floresta atlântica e o interior no Sul do Brasil A Floresta Atlântica é reconhecida mundialmente como um hotspot devido à sua megadiversidade. Estima-se que nesse bioma existam cerca de 20 mil espécies de plantas, o que representa 35% das espécies existentes no Brasil. Este estudo teve como objetivo avaliar se há diferenças na diversidade florística e estrutural do componente herbáceo em uma região de transição e no interior da Floresta Atlântica no sul do Brasil. O estudo foi desenvolvido em um fragmento florestal de 13 hectares localizado no estado de Santa Catarina, sul do Brasil. A borda do fragmento é caracterizada por uma área com largura de até 10-15m, coberta massivamente por vegetação herbácea-arbustiva e raros indivíduos arbóreos. O interior é sombreado de forma descontínua pelo componente arbóreo e arbustivo presente nos estratos superiores da floresta. O levantamento fitossociológico utilizou o método de parcelas, sendo estabelecidas 100 parcelas de 1 m², 50 na borda do fragmento florestal e 50 no interior, obtidas em transectos lineares de 20m. Os parâmetros fitossociológicos estudados para ambas as áreas foram ISSN:1984-2295 Revista Brasileira de Geografia Física Homepage:https://periodicos.ufpe.br/revistas/rbgfe