No abstract

The conversion of old-growth into secondary forest changes profoundly the community structure of most plant life-forms, including the communities of terrestrial herbs. Here, we verify how herb communities are affected by environmental variables of old-growth and secondary stands of South Brazilian Atlantic Forest. We identified all herbaceous species and estimated their frequency and cover in 16 plots of 6 9 6 m in each forest type. We used the structural characteristics of the tree component (i.e., basal area, density, average height and canopy openness) and soil parameters as environmental variables of each forest. Results showed that old-growth and secondary forests have distinct herb composition, with the later showing higher plant cover and species diversity. Canopy openness and soil parameters explained part of the variation in herb composition between forests. Herb cover and richness responded positively to soil fertility in both forests, and in secondary forest these two descriptors were also positively correlated with canopy openness. The abiotic differences between forests allowed the establishment of herbaceous species with different ecological requirements, especially in the secondary forest, marked by input of species typically found in disturbed environments. These species contribute to the higher cover values and species richness in secondary forest. Our findings suggest that changes in environmental conditions in a forest substantially change the herb community. Because of their importance as environmental indicators, herb communities can contribute to a better understanding of successional patterns in the Atlantic Forest.

ResumoEste estudo teve por objetivo realizar levantamento florístico e fitossociológico, bem como analisar a distribuição espacial do componente epifítico vascular em um fragmento florestal em área urbana pertencente à floresta ombrófila densa submontana no município de Criciúma-SC. Adicionalmente, informações sobre os grupos ecológicos das espécies epifíticas e as estratégias de polinização e de dispersão também são apresentadas. Foram amostradas 60 árvores como forófitos com DAP ≥ 10 cm, pelo método de pontos quadrantes centrados, e foi utilizado o método expedito por caminhamento para registrar as espécies epifíticas não amostradas nos forófitos pelo método fitossociológico. A frequência foi avaliada com base na ocorrência dos epífitos nos forófitos e nos segmentos fuste e copa, quando registrada a presença dos epífitos nos dois segmentos. Foram encontradas 65 espécies distribuídas em 39 gêneros e em 14 famílias, das quais 49 foram amostradas no levantamento fitossociológico e as demais no levantamento por caminhamento. Bromeliaceae apresentou a maior riqueza, seguida de Orchidaceae e Cactaceae. Tillandsia recurvata (L.) L. foi citada pela primeira vez para o sul do estado. A diversidade específica foi estimada em H' = 3,33 e a equabilidade (E) foi igual a 0,86. O grupo ecológico dos holoepífitos foi o mais representativo na área de estudo. Entomofilia e anemocoria foram as estratégias predominantes para polinização e dispersão, respectivamente. species and the strategies for pollination and dispersal were also presented. One sampled 60 trees as phorophytes with DBH ≥ 10 cm, through the point-centered quarter method, and the expeditious walking method was used for recording the epiphytic species which weren't sampled in the phorophytes through the phytosociological method. The frequency was evaluated having the occurrence of epiphytes in the phorophytes and the segments on the bole and crown as a basis. One recorded the presence of epiphytes in the phorophytes in the segments on the bole and crown. One found 65 species distributed into 39 genera and 14 families, out of which 49 were sampled in the phytosociological survey and the remaining ones in the walking survey. Bromeliaceae showed the highest richness, followed by Orchidaceae, and Cactaceae. Tillandsia recurvata (L.) L. was firstly mentioned in the southern state. The specific diversity was estimated as H' = 3.33 and evenness (E) was equal to 0.86. The ecological group of holoepiphytes was the most representative one in the area under study. Entomophily and anemochory were the prevailing strategies for pollination and dispersal, respectively. In the phytosociological survey, the number of epiphytic species in the phorophytes ranged from 0 to 21. The highest importance values were those related to Rhipsalis teres (Vell.) Steud. and Microgramma vacciniifolia (Langsd. & Fisch.) Copel.

RESUMO-As trepadeiras são importantes na composição e estrutura das fl orestas tropicais e subtropicais. No presente estudo foi realizado levantamento fl orístico e fi tossociológico das comunidades de trepadeiras no Parque Estadual da Serra Furada, Sul de Santa Catarina, Brasil. A fl ora local foi amostrada por meio de caminhamento exploratório, em áreas alteradas, enquanto que os dados estruturais foram registrados em áreas do interior da fl oresta. Foram amostradas 70 espécies, sendo 44 lenhosas e 26 herbáceas. As famílias de maior riqueza específi ca foram Asteraceae (14), Bignoniaceae (12) e Apocynaceae (oito). A estratégia de dispersão mais frequente foi anemocoria. Mickelia scandens (Raddi) R.C. Moran foi a espécie mais abundante e com maior Índice de Valor de Importância. O mecanismo de escalada com maior ocorrência foi o volúvel, enquanto em abundância o radicante. O estudo traz contribuições ao conhecimento da fl ora de trepadeiras do Sul do Brasil, visto que inclui as trepadeiras herbáceas, que raramente estão em estudos quantitativos deste grupo de plantas. Palavras-chave: herbácea, lenhosa, mecanismo de escalada ABSTRACT-Floristic composition and community structure of climbers from the Atlantic Rain Forest in southern Santa Catarina, Brazil. Climbers are important for the composition and structure of tropical and subtropical forests. This study aimed to analyze the fl oristic and community structure survey of climbers in the Parque Estadual da Serra Furada, in southern Santa Catarina, Brazil. The fl oristic survey was carried out in disturbed areas by the walking method, and the structural survey was conducted in inland areas of the forest. Seventy species of climbers were recorded, 44 were woody and 26 were herbaceous. The most representative families were Asteraceae (14), Bignoniaceae (12) and Apocynaceae (eight). Anemochory was the most common dispersion strategy. Mickelia scandens (Raddi) R.C. Moran was the most abundant species and had the highest Importance Value Index. Voluble was the climbing mechanism most found, while radicant was most abundant. This study contributes to the knowledge of vine fl ora from southern Brazil, including herbaceous climbers, rarely included in quantitative studies of this plant group.