& Methods Data from 418 sample plots were used to adjust generic models for forest types and specific models for 15 species. Regression assumptions, modelling efficiency, lack of fitness, goodness of fit and comparison between species-specific and generic models were assessed by analytical methods. & Results Logarithmic models presented the best results of adjustment and evenness of residual variance. Lack of fit F test showed acceptable adjust quality for nearly all speciesspecific and generic models; R 2 adj * and modelling efficiency measure presented values close to 1 for all fitted models; model identity F test showed differences between specific and generic models in some cases. & Conclusion Since regression assumptions were satisfied and because of their quality of fit, the fitted models compose useful tools for predicting total stem volume (with bark) for forest remnants in southern Brazil. Stratification of datasets by forest type for model fitting showed to be necessary, but, commonly, generic models for forest types produced estimates not less reliable than species-specific models.
Th e eff ect of environmental variables on the plant species distribution in the Atlantic Forest raises the interest of researchers, but few studies, mainly at local scales, analyzed the infl uence of spatial factors on the environment and species distribution. Linear models and spatial correlograms were used to evaluate whether environment and space may predict variations in species composition of trees and shrubs in a Subtropical Rainforest remnant. Th e study area was divided in 25 plots of 400 m², systematically distributed, where individuals with DBH ≥ 5 cm were measured. Elevation and slope were the most important predictors of the fl oristic variations, but space, generally neglected in researches on South American's vegetation, had a relevant infl uence, as a structural component, in terms of environmental variables, and as intrinsic biological component, here probably as result of constraints in species dispersion. Although the origin of great part of the variation in species composition remained unknown, which is common in studies on vegetation, results indicated, for the fi rst time, the complex role of spatial and environmental variables in the composition of trees and shrub species in a Subtropical Rainforest of Brazil.
RESUMOA regeneração natural é considerada uma das técnicas mais adequadas para promover o restabelecimento da vegetação em áreas degradadas. Assim, o presente estudo teve por objetivo avaliar a composição e estrutura dos estratos arbóreo e regenerativo em três áreas sob regeneração natural, caracterizados por diferentes idades após retirada de povoamentos de Eucalyptus grandis. A área de estudo localiza-se na bacia hidrográfica do rio Itajaí, em Brusque -SC. A coleta dos dados foi realizada com a implantação de 56 unidades amostrais (UA) de 200 m² distribuídas ao longo das margens de um curso d'água em áreas que apresentavam períodos de cinco (AT I), três (AT II) e um e meio (AT III) anos de abandono. Em cada UA foram amostrados os indivíduos vivos com PAP ≥ 5 cm e altura maior que 1,3 m. Para o levantamento do estrato regenerativo, foi demarcada uma subunidade de 20 m² dentro de cada UA do estrato arbóreo, no qual foram amostradas as plantas com altura ≤ 1,30 m. A vegetação estudada apresentou distinções em valores estruturais, evidenciando um dinamismo sucessional no período avaliado. As pioneiras sofreram decréscimo em número de espécies, tanto no estrato arbóreo quanto no regenerativo, enquanto que as espécies clímax tolerantes à sombra apresentaram ingressos com o avanço da idade de abandono das áreas. O número de indivíduos por grupos ecológicos sofreu alterações mais evidentes no estrato regenerativo com o aumento do período de abandono das áreas e as pioneiras diminuíram enquanto que as espécies clímax exigentes em luz aumentaram em densidade. Palavras-chave: composição; estrutura; restauração; mata ciliar. ABSTRACTNatural regeneration is one of the most appropriate techniques to promote the restoration of vegetation in degraded areas. Thus, this study aimed to evaluate the composition and the structure of the tree and regenerative strata in three areas under natural regeneration, characterized by different ages after the removal of stands of Eucalyptus grandis. The study area is located in the basin of Itajai river in Brusque, SC state. Data collection was performed with the deployment of 56 sample units (AU) of 200 m² distributed along the banks of a watercourse in areas that had five periods (AT I), three (AT II) and one and a half (AT III) years of abandonment. In each AU, individuals living with PAP ≥ 5 cm and height greater than 1.3 m were sampled. To survey the regenerative stratum, it was demarcated a subunit of 20 m² within each AU of
Em Santa Catarina, a Floresta Pluvial Subtropical encontra-se alterada, sobretudo em sua composição e estrutura. Assim, trabalhos que caracterizem os remanescentes florestais são importantes, pois podem servir de base para estudos de meta-análise. Neste trabalho, foi caracterizada a composição e a estrutura de uma Floresta Pluvial Subtropical e comparou-se a composição de espécies dessa floresta com outras da mesma fitofisionomia. A vegetação foi amostrada em 25 parcelas de 400 m², em que foram medidos os indivíduos com DAP ≥ 5 cm. Foram amostrados 1.727 indivíduos, distribuídos em 144 espécies, 91 gêneros e 45 famílias. Myrtaceae, Lauraceae e Fabaceae foram as famílias mais ricas, com destaque para os gêneros Ocotea, Myrcia e Eugenia. As espécies com maior percentual de importância foram Euterpe edulis Mart., Sloanea guianensis (Aubl.) Benth., Ocotea aciphylla (Nees & Mart.) Mez e Tapirira guianensis Aubl. Foram detectados dois grupos florísticos que se formaram devido à proximidade geográfica, sendo o primeiro grupo formado pelos estudos realizados na região sul-catarinense e o segundo por estudos realizados na região do Vale do Itajaí. Os resultados indicaram que a floresta é composta por espécies clímax tolerantes à sombra e pode ser caracterizada como um remanescente de vegetação bem conservado, indicando sua importância para conservação.AbstractPhytosociology of a primary Subtropical Rain Forest in southern Brazil. The Subtropical Rain Forest is altered in Santa Catarina regarding its composition and structure. Thus, the studies that focus on these forest remnants are important because they can consist as a basis for meta-analysis. In this work research we intend to characterize the composition and structure of a Subtropical Rain Forest stand and compare the species composition of this stand with others in the same forest type. The vegetation was sampled through 25 sample plots of 400 m², where individuals with DBH ≥ 5 cm were measured. We sampled 1,727 individuals belonging to 144 species, 91 genus and 45 families. Myrtaceae, Lauraceae and Fabaceae were the richest families, especially the Ocotea, Eugenia and Myrcia genus. The species with the highest importance percentual were Euterpe edulis Mart., Sloanea guianensis (Aubl.) Benth., Ocotea aciphylla (Nees & Mart.) Mez, Tapirira guianensis Aubl. We detected two floristic groups formed due to geographical proximity; the first was formed by studies conducted in the southern region and the second by studies conducted in the Itajaí Valley. Our results indicated that the studied forest stand is composed primarily of shade-tolerant climax species and can be characterized as a well-preserved forest remnant. The results indicate the importance of this area for conservation.Keywords: Composition; structure; ecological groups; similarity; Itajaí Valley.
ResumoEstudos sobre regeneração lorestal podem fornecer informações sobre as espécies que irão compor a loresta no futuro. Entretanto, poucos estudos enfatizam esse componente. Neste trabalho, avaliou-se a regeneração arbórea e arbustiva de uma Floresta Ombróila Mista em 180 parcelas de 2,5 m de raio, onde foram medidos os indivíduos com altura ≥ 50 cm e DAP ≤ 5 cm. Foram amostrados 4.078 indivíduos e 89 espécies. Os índices de Shannon (3,64) e Pielou (0,81) evidenciaram alta diversidade e equilíbrio na abundância das espécies. As espécies mais importantes da regeneração foram Allophylus edulis, Casearia decandra, Cupania vernalis, Matayba elaeagnoides e Myrsine coriacea. Os resultados mostram que nem todas as espécies mais importantes apresentam tendência à forma de J-invertido, evidenciando que pode estar havendo desequilíbrio entre as taxas de mortalidade e recrutamento dos indivíduos dessas espécies na regeneração.Palavras-chave: Distribuição de alturas; Fitossociologia; Floresta de Araucária; Regeneração lorestal; Riqueza de espécies AbstractRegeneration of a Mixed Ombrophilous Forest on the Santa Catarina Plateau. Studies on forest regeneration can provide information about species that will form a forest in the future. However, few studies emphasize this component. This study evaluated tree and shrub regeneration in a Mixed Ombrophilous Forest using 180 sample plots with 2.5 m radius, where individuals whose height was ≥ 50 cm and diameter at breast height (DBH) was ≤ 5.0 cm. The sample consisted of 4,078 individuals and 89 species. The Shannon index (3.64) and the Pielou index (0.81) showed a high diversity and balance regarding the abundance of
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