RESUMEN: La diversidad de especies puede contribuir a la resiliencia del ecosistema y puede evaluarse a través del banco de semillas del suelo (SSB). El SSB es un indicador del desarrollo forestal después de la ocurrencia de disturbios. Por lo tanto, este estudio tuvo como objetivo evaluar la relación de la fertilidad del suelo con el banco de semillas del suelo y la variación de la diversidad de especies en distintas etapas sucesionales después del abandono del pasto (25, 35, 45 y > 50 años). Se recogieron diez muestras de suelo por sitio, se distribuyeron en bandejas y se dispusieron en invernadero para el análisis de germinación. Los resultados indican que la diversidad de especies en el SSB es mayor en los bosques jóvenes que en los bosques maduros. Además, las características del suelo son diferentes entre las etapas sucesionales, los bosques jóvenes están asociados con una mayor disponibilidad de nutrientes. Finalmente, los bosques en etapas tempranas tienen un mayor potencial para la recuperación de áreas degradadas en relación con el banco de semillas forestales en etapas avanzadas.

SUMMARY: Species diversity can contribute to the resilience of the ecosystem and can be assessed through the soil seed bank (SSB). SSB is an indicator of forest development after the occurrence of disturbances. Thus, this study aimed at evaluating the relation of the soil fertility with the soil seed bank and the variation of seed bank species diversity at distinct successional stages after abandonment of pasture (25, 35, 45 and > 50 years). Ten samples of soil were collected per site, being distributed in trays and arranged in a greenhouse for a germination analysis. Results indicate that species diversity in SSB is higher in young forests than in mature forests. In addition, soil characteristics are different among successional stages, in which the young forests are associated with higher availability of nutrients. Finally, forests in early stages have higher potential for recovery of degraded areas in relation to the forest seed bank in advanced stages.

Abstract The highly biodiverse Atlantic Forest has been heavily exploited and its remnant areas, which are mostly composed of secondary forests, cover less than 20% of its original extension. This study analyzed the structure, aboveground biomass (AGB) and species diversity of a secondary evergreen rainforest in the state of Santa Catarina, southern Brazil. Individuals with diameter at breast height ≥ 5 cm on 22 sample plots were measured, totalizing 3.49 hectares of sampled area. A mean AGB of 201.6 Mg ha-1 (standard deviation = 35.5) was found; Hyeronima alchorneoides and Miconia cinnamomifolia represented 29.1% and 7.6% of the community AGB ha-1, respectively. A total of 153 species distributed in 107 genera and 55 families was observed; it was estimated that 121 species (95% confidence interval: [117, 125]) occurred in one hectare. These results highlight the importance of secondary forests for biodiversity restoration/conservation and carbon sequestration.

ABSTRACT The Atlantic Subtropical Rainforest covers a huge area of Santa Catarina state, starting on the coast and going through the Serra Geral. Along its distribution, the vegetation changes according to altitude, geomorphology, and soil. In the attempt to evaluate vegetation variations related to different soil types in an Atlantic Forest remnant, 43 plots of 200 m2 were sampled. All the individuals with DBH ≥ 5.0 cm were measured. We have found consistent floristic and structural variations, which separated sample plots with Litholic Neosol and Rogosol situated in slopes from those with Yellow-Red Ultisol and Haplic Cambisol, as well as plots with Fluvic Neosol from Haplic Gleisol in plateaus. Species richness increased according to water availability and soil depth, with the plateaus’ soils being the richest. Each area was characterized by a range of indicator species and the results indicated that soil attributes are important drivers of vegetation variation.

Abstract Studies about dispersal syndromes and spatial distribution can provide information about species ecology. However, few studies analyze these ecological patterns in different vegetation layers. In this work, we verified the relationship between the dispersion syndromes and the spatial distribution in different layers in Araucaria Forest. We sampled 180 plots with size and inclusion criteria that changed according to the vegetative layer. We sampled 15,545 individuals in 103 tree species. We found significant differences between the number of species in the dispersion syndromes (χ2 = 11.52; P ≤ 0.05) and spatial distribution patterns (χ2 = 10.94; P ≤ 0.05), being zoochoric and tends to clustering the most predominant. We also found a significant interaction between the dispersion syndromes and spatial distribution patterns in the analyzed layers (F = 1,044; P < 0.0001), with anemochoric species characterized by random distribution, autochoric in the cluster distribution and zoochoric in the tends to clustering. The results demonstrate that the tree species of the different layers are related to the type of dispersion and the aggregation pattern.

RESUMO A 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.

ABSTRACT Natural 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 tree communities where the plants were sampled with height ≤ 1,30 m. The studied vegetation presented distinctions in structural values, showing a succession dynamics during the study period. The pioneering suffered decrease in number of species, both in the tree layer as the regenerative, while shade-tolerant climax species had recruitments along with the advancement of the age of abandoned areas. The number of plants for ecological groups showed more pronounced changes in the regeneration layer with the increased abandonment period of areas and pioneer species decreased while the demanding climax light increased in density.

ABSTRACT The effect 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 influence 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. The 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 floristic variations, but space, generally neglected in researches on South American's vegetation, had a relevant influence, 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 first time, the complex role of spatial and environmental variables in the composition of trees and shrub species in a Subtropical Rainforest of Brazil.

<p>Em florestas naturais, a altura total das árvores (h) é, muitas vezes, difícil de medir. Nesses casos, modelos de regressão baseados em variáveis de fácil medição, como o DAP (d), são uma alternativa, desde que seus pressupostos sejam atendidos. Neste estudo, objetivou-se i) o ajuste de modelos hipsométricos para três tipologias florestais de Santa Catarina (Floresta Estacional Decidual, Floresta Ombrófila Mista, Floresta Ombrófila Densa), testando os pressupostos e avaliando a qualidade dos ajustes; ii) verificação de diferenças das relações hipsométricas entre as tipologias florestais e entre os modelos ajustados baseados em alturas medidas e estimadas. Os dados de 1.766 alturas medidas e 3.150 alturas estimadas em campo foram coletados pelo Inventário Florístico Florestal de Santa Catarina (IFFSC), em 418 unidades amostrais. Os modelos foram ajustados para ambos os conjuntos de dados. Modelos específicos foram ajustados para espécies com ≥ 30 árvores medidas; normalidade, aleatoriedade e homoscedasticidade dos resíduos foram avaliadas analiticamente. Bandas com intervalos de confiança foram construídas pelo método Working-Hotelling; teste z para médias foi aplicado para comparar os modelos baseados nos dois conjuntos de dados. Parâmetros estatísticos como o AIC evidenciaram melhor ajuste dos modelos logarítmicos. Foram encontradas diferenças nas relações h/d entre as tipologias florestais (DEN e MIX) e entre os conjuntos de dados. O uso de modelos hipsométricos é uma alternativa para estudar a relação h/d e para determinar padrões da estrutura vertical em comunidades florestais, quando a medição de h não é viável, embora em casos da necessidade de maior acurácia das alturas estimadas, os modelos nem sempre possam fornecê-las.</p>

<p>Total tree height (h) is often difficult to measure in natural forests. Regression models based on easily accessed variables like DBH (d) can be an alternative, since their assumptions are validated. The aims of this study are to: (i) calibrate specific and generic h-d models for three forest types (Seasonal Deciduous Forest, DEC; Mixed Ombrophilous Forest, MIX; and Dense Rainforest, DEN) in Santa Catarina state testing the regression assumptions and evaluating model quality; (ii) verify different h-d relationship between forest types. The dataset (1,766 measured tree h and 3,150 estimated h) was collected by Santa Catarina Forest and Floristic Inventory (IFFSC) in 418 systematically located sample plots. Models were calibrated for two datasets, one containing hypsometer measurements, the other h estimations made by field crews. Specific models were calibrated for species with at least 30 sampled trees. Residual normality, randomness and heteroskedasticity were evaluated by analytical methods. Confidence bands were generated by the Working-Hotelling method; z test for means was applied to compare models based on the two databases. The statistical parameters such as corrected Akaike Information Criterion provided evidences that logarithmic models were better adjusted to the data. Both datasets were statistically different for DEN and MIX. Differences in h-d relationships were found between forest types. The use of calibrated h-d models is an alternative for studying the relationships between these variables and to assess vertical structure patterns of forest communities, when h measurements are not feasible, although, for situations that more accurate h values are needed, they will not always provide reliable predictions.</p>

Baseado na Teoria Geral dos Sistemas desenvolveu-se um modelo ecológico para a restauração dos ecossistemas, cujos solos estejam muito degradados, tratando o ecossistema como um sistema dinâmico complexo, hipersensível às condições iniciais de preparação do solo. Partindo da hipótese de que os ecossistemas degradados são sensíveis às condições iniciais de preparação do solo, avaliou-se a técnica das rugosidades (variações do relevo, alternando superfícies côncavas e convexas) para desencadear, ao longo do tempo, propriedades emergentes que aceleram o processo de restauração ecológica. Os ecossistemas degradados podem ser entendidos como sistemas organizacionalmente abertos, como uma estrutura dissipativa, em que fluem matéria e energia, irreversivelmente. A principal tarefa, em restauração ecológica, em áreas que tiveram o solo degradado consiste em obter a internalização da matéria e da energia para induzir o sistema ao fechamento organizacional. As rugosidades, representadas pelas microtopografias do solo, constituem uma técnica eficiente na internalização de matéria, retendo água, sedimentos, matéria orgânica, nutrientes e sementes. As variações do relevo desencadeiam, ao longo do tempo, mudanças ambientais de uma forma dinâmica e heterogênea que influenciam as interações entre a radiação solar, a umidade e os nutrientes, criando oportunidades diferenciadas para as espécies vegetais e animais. Deve haver uma concentração orientada para as estruturas de fluxos e de processos existentes entre o ecossistema degradado (sistema) e o ambiente (vizinhança). Nessa abordagem dedica-se uma concentração especial nas inter-relações entre o sistema degradado e o ambiente. Para restauração ecológica, cuja área esteja com solo degradado, como a mineração e a pecuária, propõe-se uma nova abordagem sistêmica integradora na qual as rugosidades do solo possam desencadear espacial e temporalmente, padrões e propriedades ambientais emergentes devido à hipersensibilidade às condições iniciais de preparação do terreno.

Based on the general systems theory, an ecological model for the restoration of ecosystems has been developed, which soils are highly degraded, and treating the ecosystem as a complex dynamic system, hyper-sensitive to initial conditions of soil preparation. Assuming that degraded ecosystems are sensitive to initial conditions of soil preparation, the technique of roughness was evaluated (relief variations alternating between concave and convex surfaces) to trigger over time emergent properties that accelerate the process of ecological restoration. The degraded ecosystems can be understood as organizationally open systems, as a dissipative structure, in which irreversibly matter and energy flow. The main task in ecological restoration in areas that had the soil degraded is to achieve the internalization of matter and energy to induce the system to organizational closure. The roughness, represented by soil micro-topography is an effective technique in the internalization of matter, retaining water, sediment, organic matter, nutrients and seeds. Variations of relief trigger environmental changes over time in a dynamic and heterogeneous way, which influence the interactions between solar radiation, moisture and nutrients, creating different opportunities for plants and animal species. There must be an oriented concentration to flow structures and processes between the degraded ecosystem (system) and the environment (neighborhood). In this approach, a particular concentration on the interrelationships between the system and the environment is dedicated. For ecological restoration, whose area is with degraded soil, such as mining and ranching, a new integrative degraded systemic approach is proposed, in which the roughness of the soil might trigger spatial and temporal patterns and emergent environmental properties due to the hyper-sensitivity to initial conditions of the land preparation.

O objetivo deste estudo foi avaliar o processo de crescimento do Eucalyptus grandis quando submetido à irregularização do terreno. Baseando-se na "Ótica da Teoria do Caos" e partindo-se da hipótese de que as áreas reflorestadas por E. grandis são consideravelmente sensíveis às condições iniciais de preparação do solo, aplicou-se a técnica das rugosidades (variações do relevo alternando superfícies côncavas e convexas) para desencadear ao longo do tempo propriedades emergentes que aceleram o processo de crescimento vegetal. A área de estudo localiza-se na Bacia Hidrográfica do Rio Itajaí, em Brusque, SC. Esta foi dividida em quatro parcelas menores: duas com tratamentos irregulares (IR-A e IR-B) e outras duas com tratamentos regulares (R-A e R-B). Os tratamentos irregulares consistiram na abertura de cavas, utilizando-se uma retroescavadeira hidráulica, intercaladas com 1 m de largura, 4 a 5 m de comprimento e 0,5 m de profundidade. Nos tratamentos regulares foi adotado o cultivo mínimo do solo, onde o preparo do solo ficou restrito às linhas ou covas de plantio. Na análise do desenvolvimento de E. grandis (altura, diâmetro do colo e na altura do peito - DAP) verificou-se diferenças estatísticas entre as técnicas de preparação do solo, sendo os maiores valores nos tratamentos irregulares. Nas parcelas irregulares (IR-A e IR-B) foram encontrados os maiores valores médios de altura (5,29 m e 5,46 m), diâmetro do colo (45,65 mm e 45,4 mm) e DAP (4,44 cm e 4,79 cm), respectivamente. Pressupõe-se que as rugosidades funcionaram efetivamente como componentes auxiliares na internalização da matéria, retendo água, sedimentos e nutrientes, fato que deve ter potencializado e acelerado o crescimento do E. grandis.

The aim of this study was to evaluate the process of growth of Eucalyptus grandis non-regularization when subjected to the ground. Relying on "Optical Chaos Theory" and starting from the assumption that the reforested areas by E. grandis are considerably sensitive to the initial conditions of soil preparation was applied the technique of roughening (variations relief alternating concave and convex surfaces) to cause over time emergent properties that accelerate the process of plant growth. The study area is located on the Itajai River Basin, in Brusque, SC. This was divided into four smaller portions: two treatments with irregular (IR-A and IR-B) and two others with regular treatments (R-A and R-B). The treatments consisted of irregular armhole opening, using a hydraulic backhoe, interspersed with 1 meter wide, 4 to 5 meters long and 0.5 meters deep. In regular treatments was adopted minimum tillage of the soil, where soil preparation was restricted to lines or planting holes. In the analysis of the development of E. grandis (height, diameter and breast height - DBH) was found statistical differences between the techniques of soil preparation, and the highest values in treatments irregular. In plots irregular (IR-A and IR-B) were found higher mean values of height (5.29 meters and 5.46 meters), stem diameter (45.65 mm and 45.4 mm) and DBH (4.44 cm to 4.79 cm), respectively. It is assumed that the roughness effectively functioned as auxiliary components in the internalization of matter, retaining water, sediments and nutrients, a fact that should have enhanced and accelerated the growth of E. grandis.