PHYTOSOCIOLOGICAL AND PHYTOGEOGRAPHIC CHARACTERIZATION OF A RIPARIAN FOREST SECTOR IN ALFREDO WAGNER, SANTA CATARINA STATE, AS SUBSIDY FOR ECOLOGICAL RESTORATION

Os conhecimentos flor\uedstico e estrutural da comunidade arb\uf3rea s\ue3o fundamentais para subsidiar estrat\ue9gias de restaura\ue7\ue3o florestal. Neste sentido, foi realizado um levantamento fitossociol\uf3gico em um fragmento florestal situado nas margens de um tribut\ue1rio do Rio Caet\ue9 em Alfredo Wagner, SC, objetivando: i) conhecer a estrutura e a flor\uedstica da vegeta\ue7\ue3o arb\uf3rea dessa floresta; ii) classificar as esp\ue9cies encontradas em grupos ecol\uf3gicos e iii) comparar a flor\uedstica da \ue1rea estudada com outros estudos realizados em Floresta Ombr\uf3fila Mista (FOM), Floresta Ombr\uf3fila Densa (FOD) e \ue1rea de transi\ue7\ue3o entre FOM-FOD de Santa Catarina. Nesse fragmento foram alocadas 10 parcelas de 400 m2 onde todos os indiv\uedduos arb\uf3reos que apresentaram Circunfer\ueancia a Altura do Peito (CAP, medido a 1,30 m do solo) igual ou superior a 15,7 cm foram medidos, marcados e identificados. As esp\ue9cies foram classificadas nos grupos sucessionais: pioneira, cl\uedmax exigente de luz ou cl\uedmax tolerante \ue0 sombra. Para a compara\ue7\ue3o flor\uedstica com outros remanescentes, foi utilizada a An\ue1lise de Correspond\ueancia Retificada (DCA). A estrutura do componente arb\uf3reo foi descrita pela densidade, frequ\ueancia, domin\ue2ncia e Valor de Import\ue2ncia (VI). Os resultados demonstram elevada riqueza flor\uedstica (98 esp\ue9cies). Foi poss\uedvel constatar esp\ue9cies t\uedpicas de FOM, como Araucaria angustifolia (Bert.) Kuntze, e esp\ue9cies caracter\uedsticas de FOD, como Byrsonima ligustrifolia A.Juss., confirmando a caracter\uedstica do fragmento estudado de pertencer a uma \ue1rea de tens\ue3o ecol\uf3gica, padr\ue3o confirmado na compara\ue7\ue3o da similaridade flor\uedstica. As esp\ue9cies com maior VI foram Psychotria vellosiana Benth., Alsophila setosa Kaulf. e Guatteria australis A.St.-Hil. Estas e outras esp\ue9cies de alto VI, por suas consider\ue1veis representatividades na \ue1rea, s\ue3o importantes na restaura\ue7\ue3o de florestas ciliares degradadas na regi\ue3o. Os plantios dever\ue3o ser planejados obedecendo-se ao grupo sucessional das esp\ue9cies, plantando-se as esp\ue9cies pioneiras e cl\uedmax exigentes de luz em um primeiro momento (e.g. Psychotria vellosiana), seguidas, quando houver o sombreamento da \ue1rea, das esp\ue9cies cl\uedmax tolerantes \ue0 sombra (e.g. Alsophila setosa e Guatteria australis).The understanding of floristic and structure of tree communities is essential to subside the strategies of forest restoration. In this sense, a phyto-sociological survey was conducted in a forest fragment situated along a tributary of Caet\ue9 river, in Alfredo Wagner, state of Santa Catarina, in order to: i) know the structure of trees and flora in this forest, ii) classify the species found according to ecological groups and iii) compare the flora of the study area with other studies in Araucaria forest (FOM), Atlantic Rain Forest (FOD) and the transition area between FOM-FOD of Santa Catarina state. In this fragment, 10 plots of 400 m2 were allocated, where all individual trees with the circumference at breast height (CBH, measured at 1.30 m above the ground) greater than or equal to 15.7 cm were measured, marked and identified. The species were classified into the following succession groups: pioneer, climax light-demanding or climax shade-tolerant. The Rectified Correspondence Analysis (DCA) was used for the floristic comparison. The structure of the tree component was described by the density, frequency, dominance and importance value (VI). The results showed elevated species richness (98 species). It was found typical species of FOM, such as Araucaria angustifolia (Bert.) Kuntze, and species characteristics of FOD such as Byrsonima ligustrifolia A.Juss., confirming the study fragment as an area of ecological tension between FOM and FOD. The species with most elevated VI were Psychotria vellosiana Benth., Alsophila setosa Kaulf. and Guatteria australis A.St.- Hil. The species with elevated VI, for their considerable representation in the area, are important in the restoration of degraded riparian forests in the region. The species seedlings plantation should be planned observing the group successional of each species, planting pioneer and light-demanding climax species first (e.g. Psychotria vellosiana), followed by, after the shading of the area, shade-tolerant species (e.g. Alsophila setosa e Guatteria australis)