Abstract:-(Spatial distribution pattern and size structure of tree species and its structuring factors in a fragment of the Brazilian cerrado). The aim of this study was to analyze population structure and spatial distribution pattern of five tree species in a fragment of cerrado stricto sensu in the southwest of the Goiás State, Brazil. Fifty quadrats of 10 × 10 m (100 m 2 ) were surveyed, and all individuals within each quadrat were sampled. The theoric distributions of Poisson and Negative Binomial and two indices o… Show more
“…The vegetation dynamics showed that the number of recruits was higher than number of dead trees in all periods and areas measured. This result points out to the self-regeneration behavior of the vegetation (Bernasol & Lima-Ribeiro, 2010;Mews et al, 2011;Carvalho, Fagg, & Felfili, 2010). Accordingly, the recruitment rate stood out in relation to mortality rate in all areas, in the respective time intervals.…”
The Cerrado has a wide diversity of fauna and flora, and the knowledge of its horizontal structure, in different time intervals allows the prediction of its structural and floristic characteristics. The aim of this study was to evaluate the changes in structure and composition of tree community in three fragments of Cerrado with low anthropization, in an interval of 11 years at Minas Gerais state. Rectangular plots of fixed size were sampled, measuring stem diameter and height of all living arboreal individuals with diameter at 1.30 meters above ground (DBH) ≥ 5 cm. The tree vegetation dynamics study of the areas was performed, as well as the floristic analysis and the diametric structure. Considering all fragments and years of measurement, the recruitment of trees surpassed its mortality. The basal area varied between 3.67 and 13.07 m².ha-1. The studied areas, considering all fragments and years of measurement, showed a Shannon diversity index (H') from 3.43 to 3.87 nat.ind-1 and Pielou equitability index (J') ranged an interval between 0.77 and 0.82. The similarity calculated by the Jaccard index (J), when performed per plot considering the three fragments, showed a value of 0.2653. Also, related to the development and growth of the study areas, it can be inferred that all fragments and their respective years of measurement had a J-inverse pattern. In conclusion, it can be inferred that the three fragments maintained a representative growth in number of individuals and basal area.
“…The vegetation dynamics showed that the number of recruits was higher than number of dead trees in all periods and areas measured. This result points out to the self-regeneration behavior of the vegetation (Bernasol & Lima-Ribeiro, 2010;Mews et al, 2011;Carvalho, Fagg, & Felfili, 2010). Accordingly, the recruitment rate stood out in relation to mortality rate in all areas, in the respective time intervals.…”
The Cerrado has a wide diversity of fauna and flora, and the knowledge of its horizontal structure, in different time intervals allows the prediction of its structural and floristic characteristics. The aim of this study was to evaluate the changes in structure and composition of tree community in three fragments of Cerrado with low anthropization, in an interval of 11 years at Minas Gerais state. Rectangular plots of fixed size were sampled, measuring stem diameter and height of all living arboreal individuals with diameter at 1.30 meters above ground (DBH) ≥ 5 cm. The tree vegetation dynamics study of the areas was performed, as well as the floristic analysis and the diametric structure. Considering all fragments and years of measurement, the recruitment of trees surpassed its mortality. The basal area varied between 3.67 and 13.07 m².ha-1. The studied areas, considering all fragments and years of measurement, showed a Shannon diversity index (H') from 3.43 to 3.87 nat.ind-1 and Pielou equitability index (J') ranged an interval between 0.77 and 0.82. The similarity calculated by the Jaccard index (J), when performed per plot considering the three fragments, showed a value of 0.2653. Also, related to the development and growth of the study areas, it can be inferred that all fragments and their respective years of measurement had a J-inverse pattern. In conclusion, it can be inferred that the three fragments maintained a representative growth in number of individuals and basal area.
“…O padrão de distribuição espacial agregada é comum entre outras espécies arbóreas (SOUZA; COIMBRA, 2005; ALMEIDA; CORTINES, 2008;BENASOL;LIMA-RIBEIRO, 2010;BRUZINGA et al, 2013). Dessa forma, os processos que atuam de forma negativa sobre a espécie estudada também podem ter efeitos pungentes sobre outras espécies com distribuição parecida.…”
RESUMOEntender os padrões de estrutura e distribuição espacial das espécies de árvores é fundamental para prever a variação espacial de processos sucessionais, genéticos e ecológicos de um ecossistema florestal. Neste estudo foram analisadas a estrutura populacional e a distribuição espacial de Theobroma speciosum (cacauí) em três fragmentos florestais urbanos (Parques C/E com 6,72 ha amostrados, J com 3,92 ha e Zoobotânico com 15,84 ha) em Alta Floresta e no Parque Nacional do Juruena -PNJu (com 3,2 ha amostrados) no norte do estado de Mato Grosso. Foram amostrados 323 indivíduos de Theobroma speciosum, sendo 50 no fragmento do Parque C/E (7,44 ind. ha -1 ), 32 no Parque J (8,16 ind.ha -1 ), 76 no Parque Zoobotânico (4,79 ind. ha -1 ) e 165 no PNJu (51,56 ind. ha -1 ). A menor densidade de indivíduos encontrada nos parques urbanos pode estar relacionada com o processo de fragmentação, visto que não houve uma relação positiva da densidade e do número de indivíduos com a área amostral. Além disso, a maior densidade foi encontrada no PNJu, que é uma unidade de conservação de floresta contínua e com nenhuma intervenção antrópica recente. Os fragmentos florestais urbanos (com exceção do Parque Zoobotânico) apresentaram uma menor quantidade de indivíduos nas classes inferiores de diâmetro (0-5 cm) e altura (0-5 m) com relação à estrutura encontrada no PNJu. Essa diferença provavelmente deve-se à menor área dos Parques C/E e J e consequentemente a um efeito de borda mais intenso que afetou a regeneração florestal. O padrão de distribuição dos indivíduos em todas as populações foi agregado. Esses resultados indicam que a espécie é susceptível à fragmentação provavelmente devido ao isolamento, pois apresenta autoincompatibilidade e uma dispersão zoocórica limitada. Palavras-chave: cacauí; Amazônia; ecologia florestal.
“…The studied populations did not present a diametrical distribution in the form of "inverted J", that is, in which the number of individuals is reduced from the smallest diameter classes to the largest. The distribution of individuals in the form of "inverted J" is reported by several authors as an indicator of population stability and ability to self-regenerate and reproduce under closed canopy (Gonçalves & Santos, 2008;Bernasol & Lima-Ribeiro, 2010;Figueiredo Filho et al, 2010;Abreu et al, 2014;Silva et al, 2015). In areas 2, 3 and 4, the distribution was characterized as "bell-shaped" (Bernasol & Lima-Ribeiro, 2010), that is, with most individuals in the intermediate classes.…”
The objective of this work was to characterize the spatial distribution pattern of the Euxylophora paraensis (yellowwood), to support conservation strategies of this species population in a managed 'terra firme' forest in the state of Pará. The study area is located in Fazenda Rio Capim, which belongs to The CKBV Florestal Ltda., in the municipality of Paragominas. For analyzing the spatial distribution of trees, geostatistics was used, based on the semivariogram modeling and kriging mapping. All evaluations had better adjustment to the spherical model, presenting the highest coefficient of determination in relation to the other models tested. Euxylophora paraensis presented an aggregate distribution pattern in the study forest, with spatial dependence described by the spherical model, forming tree clusters of size from 300 to 1000 m.
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