EVALUATION OF THE NATURAL REGENERATION IN A RESTORATION PLANTING AREA AND IN A REFERENCE RIPARIAN FOREST

Abstract

\uc1reas ribeirinhas s\ue3o foco recorrente de restaura\ue7\ue3o ecol\uf3gica, devido a sua import\ue2ncia para a manuten\ue7\ue3o de servi\ue7os ecossist\ueamicos. Entretanto, poucos estudos t\ueam de fato avaliado o sucesso de interven\ue7\uf5es ativas em restaurar fun\ue7\uf5es ou processos ecossist\ueamicos. A regenera\ue7\ue3o natural \ue9 um processo sucessional, cuja avalia\ue7\ue3o pode indicar o estado e o potencial de resili\ueancia do ecossistema em \ue1reas sob restaura\ue7\ue3o. O presente estudo comparou padr\uf5es de regenera\ue7\ue3o natural de uma \ue1rea de restaura\ue7\ue3o ecol\uf3gica (com plantio de mudas nativas h\ue1 10 anos) com a mata ciliar de refer\ueancia, em Cachoeirinha, Rio Grande do Sul, Brasil. Para tanto, foi realizado o levantamento das esp\ue9cies arb\uf3reas e arbustivas presentes no estrato superior (DAP 65 5 cm) e inferior (altura > 30 cm e DAP < 5 cm), em 40 parcelas de 100 m\ub2 cada, considerando o plantio (restaura\ue7\ue3o) e a mata ciliar remanescente (refer\ueancia). Cada estrato e tratamento (refer\ueancia vs. restaura\ue7\ue3o) foi avaliado quanto aos descritores fitossociol\uf3gicos, padr\uf5es de estrutura e composi\ue7\ue3o, riqueza e similaridade entre as comunidades. Os resultados demonstraram que a \ue1rea de restaura\ue7\ue3o apresenta composi\ue7\ue3o de esp\ue9cies e estrutura diferenciada com rela\ue7\ue3o \ue0 refer\ueancia, especialmente para o estrato superior. No estrato inferior (regenera\ue7\ue3o natural), o n\ufamero de indiv\uedduos, a altura m\ue9dia e a riqueza de esp\ue9cies j\ue1 n\ue3o diferiram da refer\ueancia. A composi\ue7\ue3o de esp\ue9cies em regenera\ue7\ue3o ainda foi distinta, por\ue9m, esta foi mais similar entre si do que as demais compara\ue7\uf5es entre estratos, indicando que esp\ue9cies n\ue3o plantadas foram capazes de se estabelecer nas \ue1reas de restaura\ue7\ue3o.Riparian areas are a recurrent focus of ecological restoration due to their importance for the maintenance of ecosystem services. However, few studies have evaluated the success of active interventions in restoring ecosystem functions and processes. The natural regeneration is a successional process and its evaluation might reveal the state and the potential of the ecosystem resilience in forest areas undergoing restoration. The present study aimed to compare natural regeneration of a riparian area that is undergoing restoration (planting of native trees, 10 years ago) with a reference forest area, in Cachoeirinha, Rio Grande do Sul state, Brazil. We conducted a survey of trees and shrubs in the upper stratum (DBH 65 5 cm) and the lower stratum (> 30 cm in height and DBH > 5 cm) in a total of 40 plots (100 m2 each), within the planting (restoration) and the remnant forest (reference). For each stratum and treatment (reference vs. restoration) we analyzed phytosociological parameters, patterns of structure and composition, and similarity among plots. The results showed significant differences in relation to structure and species composition, especially for the upper stratum. For the lower stratum (natural regeneration), abundance, height, and species richness were similar between the restoration and the reference areas. Species composition in regeneration remained distinct. However, its similarity value was higher than any other comparison among strata, indicating that species that were not planted were able to establish in the planted areas