Fabrício Alvim Carvalho

Composição e riqueza florística do componente arbóreo da Floresta Atlântica submontana na região de Imbaú, Município de Silva Jardim, RJ

This study aimed to evaluate tree floristic composition of the submontane Atlantic Forest in the Imbau region, Silva Jardim, Rio de Janeiro. About 50 years ago, the forest fragmentation process was begun in this region due to farming practices. Five forest remnants were selected and four plots (100×5 m) were systematically located in each one. All trees with dbh > 5 cm were sampled and identified. In the one-hectare sample area, 161 species in 39 families were sampled. Species similarity was high between fragments (Morisita index ranging from 0.36 to 0.79). The families Leguminosae, Lauraceae and Rubiaceae showed the highest values of species richness. The studied area had a high density of early secondary species and a decrease in canopy species richness when compared to a mature forest nearby. These results indicated characteristics of secondary forests. When compared to 17 forests of Rio de Janeiro State, the Imbau region showed stronger floristic relationships with submontane forests, especially those geographically closer. Due to its ecological importance for the local flora and fauna, plus the advanced stage of fragmentation in the region, the Imbau region should be considered as a priority area for adopting conservation and management practices.

Composição, riqueza e heterogeneidade da flora arbórea da bacia do rio São João, RJ, Brasil

RESUMO – (Composicao, riqueza e heterogeneidade da flora arborea da bacia do rio Sao Joao, RJ, Brasil). Estudos floristicos vem apontando a regiao da bacia do rio Sao Joao, no Estado do Rio de Janeiro, como detentora de uma riqueza e diversidade de especies arboreas particularmente altas. Entretanto, tais afirmativas sao baseadas em estudos locais, nao existindo ainda uma analise de sua flora arborea em nivel regional. A partir da compilacao de inventarios floristicos e fitossociologicos de 20 trechos de floresta ombrofila de baixada (30-300 m), o presente trabalho aborda a composicao, riqueza e heterogeneidade da flora arborea da bacia do rio Sao Joao. A compilacao incluiu apenas as arvores com DAP ≥ 2,5 cm, que foram identificadas em nivel especifico. A amostra da flora arborea totalizou 460 especies, 231 generos e 62 familias. Estes numeros reafirmam que a regiao e realmente detentora de uma flora arborea com alta diversidade, inclusive com diversas especies raras ou vulneraveis a extincao, podendo ser considerada como uma das mais ricas entre as de Floresta Atlântica do Sudeste brasileiro. Analises multivariadas detectaram uma alta heterogeneidade floristica entre os fragmentos florestais, contribuindo na elevada riqueza regional encontrada. Os padroes de similaridade sugerem que a principal fonte desta heterogeneidade provem dos diferentes estados de conservacao das areas. Palavras-chave: analise multivariada, conservacao, Floresta Atlântica ombrofila de baixada, flora regional

Síndromes de dispersão de espécies arbóreas de florestas ombrófilas submontanas do estado do Rio de Janeiro

This study aimed to evaluate the differences between propagule dispersal syndromes of woody species in secondary and mature submountaine ombrophilous forests in the State of Rio de Janeiro, Brazil. The hypothesis is that secondary forests will show lower richness and density of woody species with biotic seed dispersal modes (zoocory). Lists of seven secondary and five mature forests were used. The averages of the proportions of biotic modes between secondary and mature forests were compared through U test. Secondary and mature forests differed statistically in richness and density of biotic species (P < 0.01). These proportions were lower in the secondary forests, according to the hypothesis. Secondary forests also showed a decrease in the density of zoocoric species dispersed by large vertebrates, belonging to Lauraceae, Myrtaceae e Sapotaceae. Further management and conservation practices in these secondary forests must need incorporate the plant-dispersers interactions, due to risks in the forest regeneration process without the adequate dispersal fauna.

Estrutura e diversidade arbórea da Floresta Estacional Semidecidual secundária no Jardim Botânico da Universidade Federal de Juiz de Fora

Este estudo avaliou a estrutura e diversidade da comunidade arborea da Floresta Estacional Semidecidual secundaria no Jardim Botânico da UFJF (Juiz de Fora, MG). As arvores (DAP ≥ 5 cm) foram amostradas em 25 parcelas aleatorias de 20 × 20 m. Foram amostrados 2.535 individuos, sendo 385 mortos em pe e 2.150 individuos vivos, pertencentes a 105 especies e 39 familias. Como reflexo da forte dominância ecologica, o valor do indice de diversidade de especies de Shannon (H’ = 3,30 nats.ind -1 ) foi baixo em comparacao com florestas mais maduras da regiao. As arvores mortas em pe representaram 15,2% do total de individuos, valor elevado quando comparado com outras florestas da regiao. Uma analise de correspondencia distendida (DCA) mostrou baixa heterogeneidade floristica interna. Houve predominância de arvores pertencentes a estagios sucessionais iniciais (pioneiras e secundarias iniciais). Os resultados demonstram que, embora o fragmento florestal possua tempo de regeneracao natural superior a 70 anos, a comunidade arborea apresenta um processo de sucessao aparentemente lento, caracteristica de uma floresta imatura. Em contrapartida, a area possui especies ameacadas de extincao e familias caracteristicas de floresta madura (Lauraceae e Myrtaceae) com boa representatividade. Assim, o fragmento e importante para a preservacao da biodiversidade regional. Tree structure and diversity in a secondary Semideciduous Seasonal Forest in the Juiz de Fora Federal University Botanical Garden Abstract This study aimed to evaluate the structure and diversity of the tree community in a secondary semidecidous forest at UFJF Botanical Garden (Juiz de Fora, Minas Gerais, Brazil). The trees (dbh ≥ 5 cm) were sampled at 25 random plots of 20 m × 20 m. A total of 2535 individuals were sampled, 385 standing dead and 2150 life, belonging to 105 species and 39 families. As a reflection of strong ecological dominance, the index value of species diversity (Shannon H ’ = 3.30 nats.ind -1 ) was low compared to secondary forests of the region. The standing dead trees represent 15.2% of individuals, a high proportion compared to secondary forests. Detrended correspondence analysis (DCA) resulted in short gradients, showing a low internal species heterogeneity. There was a strong predominance of species of early succession stages (pioneer and early secondary). The results show that, although the forest has undergone over 70 years of natural regeneration, the tree community presents a slow succession process, with low diversity and characteristics of an immature forest. In contrast, the area has endangered species and some families typical of mature forest (Lauraceae and Myrtaceae). In other words, the fragment is important for the preservation of regional biodiversity.

Persistence of Coffea arabica and its relationship with the structure, species diversity and composition of a secondary forest in Brazil

Understanding the relationships between Coffea arabica L. and the native tree community of secondary forests regrowing after the abandonment of coffee plantations is important because, as a non-native species in the Neotropics, coffee can outcompete native species, reducing diversity and forests ecosystem services. We aimed to answer three questions: 1) Does coffee regeneration in secondary forests differ between shaded and unshaded abandoned plantations?; 2) How is coffee basal area related to structural attributes, species diversity and composition of the native community?; and 3) Do the relationships between coffee and native community differ between tree and sapling components? We sampled the tree and sapling components in a seasonal tropical dry forest that were previously used as shaded and unshaded coffee plantations. Coffee was the most important species in the sapling component of shaded systems, but was almost absent in unshaded ones. Coffee basal area was negatively related with the native density and absolute species richness of the sapling component; and was negatively related with tree density, and positively related with the percentage of pioneer individuals of the native tree component. Our results indicate that coffee persists in secondary forest communities even after more than 70 years of shaded-coffee plantations were abandoned, potentially reducing density and diversity of native species. Despite limitations, which hinder more general conclusions on coffee invasiveness in Brazilian secondary tropical forests, our results indicate that coffee is a strong competitor in the studied secondary forests and provide important insights for future research on this topic.

Cost-benefit analysis of industrial and homemade dendrometer bands

Dendrometer bands are used to make repeated measurements of tree radial growth. Two types of dendrometers are used worldwide, the industrial and the homemade. Homemade dendrometers prevail in Brazilian forestry studies, but researchers have trouble constructing and installing them. An easier solution is to use industrial dendrometer bands, but they are not produced in Brazil and, therefore, are expensive and might not be appropriate for local environmental conditions. We analyzed trunk growth measurements each month (from February 2008 to January 2009) using both industrial (imported) and homemade (national components) dendrometer bands installed on 20 trees of Acacia tenuifolia in a seasonally dry forest on limestone outcrops in central Brazil. Cost-benefit comparative analysis of measurements and prices indicates that homemade dendrometer bands have all benefits, and none of the problems, of the imported industrial dendrometer bands, such as the following: (1) similar precision of measurements (correlation analysis: r > 0.930, P 0.55), (2) much lower costs (10 to 15 times cheaper), (3) easily manipulated and installated in the field, and (4) absence of some damage to tree trunks that are caused by industrial dendrometers.

Shifting species and functional diversity due to abrupt changes in water availability in tropical dry forests

Recent insights show that tropical forests are shifting in species composition, possibly due to changing environmental conditions. However, we still poorly understand the forest response to different environmental change drivers, which limits our ability to predict the future of tropical forests. Although some studies have evaluated drought effects on tree communities, we know little about the influence of increased water availability. Here, we evaluated how an increase in water availability caused by an artificial reservoir affected temporal changes in forest structure, species and functional diversity, and community‐weighted mean traits. Furthermore, we evaluated how demographical groups (recruits, survivors and trees that died) contributed to these temporal changes in tropical dry forests. We present data for the dynamics of forest change over a 10‐year period for 120 permanent plots that were far from the water’s edge before reservoir construction and are now close to the water’s edge (0–60 m). Plots close to the water’s edge had an abrupt increase in water availability, while distant plots did not. Plots close to the water’s edge showed an increase in species and functional diversity, and in the abundance of species with traits associated with low drought resistance (i.e., evergreen species with simple leaves and low wood density), whereas plots far from the water’s edge did not change. Changes in overall community metrics were mainly due to recruits rather than to survivors or dead trees. Overall stand basal area did not change because growth and recruitment were balanced by mortality. Synthesis. Our results showed that tropical dry forests can respond quickly to abrupt changes in environmental conditions. Temporal changes in vegetation metrics due to increased water availability were mainly attributed to recruits, suggesting that these effects are lasting and may become stronger over time. The lack of increase in basal area towards the water’s edge, and the shift towards higher abundance of soft‐wooded species, could reduce the carbon stored and increase the forest’s vulnerability to extreme weather events. Further “accidental” large‐scale field experiments like ours could provide more insights into forest responses and resilience to global change.

Community Succession in an Urban Novel Forest after Four Decades of Regeneration

This study aimed to analyse the tree community of an urban forest with 40 years of natural regeneration after abandonment of the degraded land. We hypothesized that after four decades of forest succession, the diversity, structure and functional aspects of the community would be similar to other secondary surrounding forests. We established ten plots (20x 20m), where all trees with DBH ≥ 5 cm were sampled. The inventory included 605 trees (1513 ind.ha-1) distributed across 25 species. The diversity index (H’ = 0.92) and basal area (10.43 m2.ha-1) were lower than in surrounding forests. The results showed a great dominance of Eremanthus erythropappus with consequent delay in successional advance, and low potential of attraction of fauna, which suggests the need for management to control its population. Understanding the functioning of novel urban forests and discussing these neglected ecosystems is fundamental to guide management actions for both human and ecosystem prosperity.

A reserva florestal legal: bases legais e análise de implantação no município de Juiz de Fora (MG) no período 2008-2010

O presente estudo teve como objetivo analisar a base legal e conceitual da Reserva Legal; os possiveis beneficios ambientais e economicos para o proprietario rural; e analisar e comparar os dados do levantamento das areas de Reserva legal averbadas no municipio de Juiz de Fora durante o periodo de 2008 a 2010 com os dados de desflorestamento ocorrido no municipio durante este periodo. Para a analise da base legal, foram feitas pesquisas bibliograficas (sites da internet) referentes a legislacao e beneficios ambientais e economicos da Reserva Legal, e foram levantados os processos administrativos encerrados/finalizados de Reserva Legal protocolados no IEF – Nucleo Operacional de Juiz de Fora durante o periodo de 2008 a 2010, e dos dados de desflorestamento ocorrido no municipio no mesmo periodo, pesquisado no banco de dados do Atlas dos Remanescentes Florestais da Mata Atlântica Periodo 2008-2010 (Fundacao SOS Mata Atlântica). As principais conclusoes foram: a manutencao e conservacao da reserva legal proporcionam ao proprietario/posseiro rural inumeros beneficios ambientais e economicos, dentre os quais a protecao e conservacao do solo, dos mananciais de agua e a fauna, o manejo florestal madeireiro e a coleta de sementes e a producao de mudas nativas; no caso em estudo, a instituicao da Reserva Legal proporcionou a protecao e conservacao de areas de florestas nativas, como tambem contribuiu para a recuperacao de areas degradadas, superando a area florestal perdida no municipio durante o periodo (2008 a 2010).

Regeneração natural e relações ecológicas com o estrato arbóreo em um fragmento urbano de floresta atlântica

O objetivo deste estudo foi avaliar a estrutura, a diversidade e as relacoes floristicas entre os estratos arboreo e regenerante de um fragmento de floresta estacional semidecidual no Campus da Universidade Federal de Juiz de Fora (mata do ICB), MG. Trata-se de um pequeno fragmento florestal (ca. 1,5 ha) oriundo de regeneracao natural apos abandono de pastagem bovina ha 40 anos atras. Ao todo, foram amostrados 920 individuos no estrato arboreo (1.533 ind.ha -1 , 48 especies), e 487 individuos no estrato regenerante (12.986 ind.ha -1 , 45 especies). Das especies mais importantes, destaque para as exoticas Pinus elliottii no estrato arboreo (VI = 15,9%) e Syzygium jambos no estrato regenerante (VI = 22,05%). Os indices de diversidade de Shannon (H’) foram baixos e estatisticamente diferentes (teste t de H’) entre os estratos (H’ = 2,84 nats.ind -1 no estrato arboreo e H’ = 2,65 nats.ind -1 no regenerante). A DCA mostrou uma grande dissimilaridade floristica entre as parcelas dos estratos arboreo e regenerante, indicando uma substituicao de especies em longo prazo. Entretanto, a baixa diversidade, mesmo apos 40 anos de sucessao, revela que a comunidade apresenta uma dinâmica sucessional com dificuldades de incorporar especies localmente raras e avancar para estagios mais maduros.