Resumo Espécies invasoras têm ocasionado a perda de biodiversidade no mundo todo por ocuparem o lugar de nativas. O presente estudo objetivou avaliar a regeneração natural ao longo do tempo em um fragmento florestal invadido por Ligustrum lucidum W.T. Aiton e Ligustrum sinense Lour. no sul do Brasil, a fim de quantificar essa invasão. Para isso, foram alocadas cinco transecções em um fragmento de Floresta Ombrófila Mista em Lages (SC), sendo cada transecção dividida em parcelas com diferentes setores de distâncias da borda e em subparcelas para avaliação do componente regenerativo. Em 2012, os regenerantes de espécies arbóreas que se encontravam nas subparcelas foram identificados, plaqueteados e divididos nas seguintes classes: classe 1 _ plantas com altura entre 10 cm e 1 m; classe 2 _ plantas com altura entre 1 e 3 m; classe 3 _ plantas com altura maior que 3 m e diâmetro medido à altura do peito (DAP) menor que 5 cm. Em 2014, esses indivíduos foram reavaliados, contabilizando os indivíduos mortos e recrutas e enquadrando os sobreviventes e recrutas nas atuais classes. Foram calculadas as taxas de mortalidade, recrutamento, mudanças de classe e mudança líquida. Os dados foram analisados por meio de uma análise de componentes principais (ACP) e tabela de contingência. Conclui-se que as espécies superaram a fase inicial do processo de invasão, demonstrando elevado incremento populacional na área estudada. Ainda, ficou evidenciado o particionamento espacial entre as espécies nativas e as exóticas, o que sugere a existência de competição interespecífica, cuja consequência pode ser a extinção local de representantes do grupo autóctone.

Abstract The replacement of native species by invasive species has caused a worldwide loss of biodiversity. This study aimed to evaluate the natural regeneration over time in a forest fragment invaded by Ligustrum lucidum W.T. Aiton and Ligustrum sinense Lour. in southern Brazil, in order to quantify this invasion. To do so, five transects were allocated in a fragment of Araucaria Forest in Lages, Santa Catarina state, with each transect divided into plots in different categories of distance from the edge and into sub-plots for the evaluation of the regenerative component. In 2012, the regenerating tree species identified in the sub-plots were tagged and classified according to height classes: Class 1, plants with height between 10 cm and 1 m; class 2, plants with height between 1 and 3 m; and Class 3, plants with a height greater than 3 m and DBH (diameter measured at breast height) less than 5 cm. In 2014, these individuals were re-evaluated, counting the dead and recruited individuals and classifying the survivors and recruits into the existing height classes. Rates of mortality, recruitment, net change, and height class changes were calculated. The data were analyzed by a Principal Component Analysis (PCA) and contingency table. It was concluded that the species overcame the early stage of the invasion process, demonstrating great population growth in the study area. Also, a spatial partitioning between native and exotic species was observed, suggesting the existence of interspecific competition, the result of which may be the local extinction of species from the autochthonous group.

ABSTRACT Pioneer species have the potential to colonize disturbed environments, contributing to the establishment of other species and driving the dynamics and advancement of the structure of forest communities. The aim of this study was to assess the evolution of floristic-structural composition in the regenerating stratum of communities formed in the Mimosa scabrella Benth. understory with different ages. The study was carried out in four municipalities located in the Santa Catarina State South Plateau, on communities with different successional ages. The plot method was applied to the survey of all arboreal individuals with height ≥ 10 cm. The floristic-structural patterns found were compatible with the expected trend of Araucaria Forest successional dynamic, showing higher richness and abundance of regenerating individuals in the older understories.

RESUMO: Foi caracterizada a demografia e o padrão espacial de uma população de erva-mate (Ilex paraguariensis A.St.-Hil) abrangendo áreas em diferentes históricos de uso (presença e ausência de gado), em Floresta com Araucárias. A coleta de dados foi realizada em três ha, metade em cada área. Foi avaliada a frequência de indivíduos por classe de altura, padrão de distribuição espacial, distribuição diamétrica (para indivíduos reprodutivos) e razão sexual. O padrão ”J” invertido foi predominante, sendo exclusivo para área com presença de gado, local que apresentou uma menor densidade de indivíduos. O padrão de distribuição espacial predominante foi o agregado, sendo que os indivíduos reprodutivos possuem preferencialmente padrão aleatório nas menores distâncias. Os resultados indicam que a presença do gado altera a densidade de I. paraguariensis e a proporção de indivíduos nas classes demográficas avaliadas.

ABSTRACT: This study characterized the demography and spatial pattern of a yerba mate (Ilex paraguariensis A.St.-Hil) population covering areas with different use histories (Presence and Absence of Cattle) in a Araucaria Forest. Data collection was performed in three ha, half in each area. The frequency of individuals by height, spatial distribution pattern, diameter distribution (for reproductive individuals) and sexual ratio were evaluated. An inverted “J” pattern predominated, being exclusive to an area with Cattle Presence, a place which presented a lower density of individuals. The predominant spatial distribution pattern was aggregated, and the reproductive individuals have a preferentially random pattern at the shortest distances. Results indicated that cattle presence changes the density of I. paraguariensis individuals and the proportion of individuals in the evaluated demographic classes.

ABSTRACT This study investigated the vegetation and environmental variable of fragments at different successional stages in a secondary riparian forest in the municipality of Ponte Alta, Santa Catarina state, Brazil (27°29’00” S and 50°17’11” W, WGS84), aiming to list priority variables for monitoring forest succession in riparian forests. For this, two areas were identified: “Reference” (conserved secondary forest) and “Restoration” (secondary forest under passive restoration). The Principal Component Analysis (PCA) indicated the existence of differences in the arboreal community diversity with lower values for the “Restoration” synthesized by PC1. The ground coverage by Ocellochloa rudis (Nees) Zuloaga & Morrone (Poaceae) was mainly in places with higher pH values and ability for effective cation exchange, with no preference of occurrence in either evaluated site. The composition of arboreal diversity was a relevant variable for monitoring passive restoration in this environment.

RESUMO Este estudo objetivou caracterizar aspectos relacionados à dispersão de propágulos de Myrceugenia euosma (O. Berg) D. Legrand (Myrtaceae) em um fragmento de Floresta Ombrófila Mista em Urupema, SC. Para isso, foram avaliados 29 indivíduos reprodutivos quanto à frequência de visitantes, chuva de propágulos, remoção e caracterização de frutos. Registraram-se 140 visitas de pássaros, sem ocorrência de período preferencial. As espécies com maior frequência de visita e maior consumo de frutos foram Zonotrichia capensis (tico-tico) e Stephanophorus diadematus (cabeça-de-velho), consideradas potenciais dispersoras. A frequência de coletores contendo propágulos de M. euosma diminuiu com o aumento da distância, apresentando comportamento distinto em função do tipo de propágulo avaliado. Também foram verificadas sementes intactas junto às fezes das aves nos coletores. A taxa de remoção de frutos depositados no chão foi de 22%, isso demonstra a relevância desse tema no processo de dispersão das espécies, merecendo atenção na realização de estudos futuros.

ABSTRACT This study aimed to characterize aspects related to propagules dispersion of Myrceugenia euosma (Myrtaceae) in a fragment of Mixed Ombrophillous Forest, Urupema, SC. For this, twenty-nine seed tree were evaluated for focal observation of visitors, propagules rain, removal and characterization of fruits. We recorded 140 visits of birds, occurring without preferential visit period. The species with higher visiting frequency and consumption of fruits were Zonotrichia capensis (Rufous-collared Sparrow) and Stephanophorus diadematus (Diademed Tanager), considered as potential dispersers. The frequency of collectors containing M. euosma propagules decreased with increased distance, presenting distinct behavior depending the type of propagule evaluated. We also found intact seeds in bird feces inside the collectors. The removal rate of fruits deposited on the ground was 22%, demonstrating that this is an important topic on the dispersal process and deserves attention in future studies.