Análise de agrupamento em remanescente de Floresta Ombrófila Mista.

Abstract

RESUMOEste estudo teve como objetivo analisar a fitossociologia de um remanescente de Floresta Ombrófila Mista. Para isso, foram utilizados seis conglomerados, cada um com 16 parcelas, onde os indivíduos arbóreos e arbustivos com circunferência à altura do peito (CAP) igual ou maior de 30 cm foram identificadas e medidas. As espécies foram classificadas em grupos ecológicos e, com base nos dados de densidade, foi realizada uma análise de agrupamento utilizando o método TWINSPAN (Two-way Indicator Species Analysis). Os agrupamentos foram caracterizados em relação a sua estrutura horizontal. Na área, foram identificadas 86 espécies, sendo 18 pioneiras, 25 secundárias iniciais, 16 secundárias tardias, 14 clímax e 13 foram classificadas em mais de um grupo. Foram identificados três agrupamentos (Grupos 1, 2 e 3), onde se destacaram as espécies Siphoneugena reitzii, Araucaria angustifolia e Sebastiania commersoniana respectivamente, em ambientes de encosta, de árvores emergentes e úmido. Constatou-se que a presença de indivíduos de menor diâmetro garantirá a permanência dessas espécies por médio prazo. Intervenções nesse ecossistema devem considerar a presença de agrupamentos distintos, caracterizados por ambiente e espécies específicas. Palavras-chave: fitossociologia; TWINSPAN; grupos ecológicos. ABSTRACTThis study aimed at evaluating the fitossociology of Mixed Rainy Forest, departing from the grouping analysis. For that, six conglomerates were used, each one with 16 plots, where the arboreal and shrub individuals with breast height circumference (CAP) equal or larger than 30 cm was identified and measured. The species were classified in ecological groups and, beginning with the density data, a grouping analysis was accomplished using the method TWINSPAN (Two-way Indicator Species Analysis). The groupings were characterized in relation to their horizontal structure. In the area, 86 species were identified, being 18 pioneers, 25 secondary initials, 16 secondary late, 14 climax and 13 were classified in more than one group. Three groupings were identified (Groups 1, 2 and 3), where the species Siphoneugena reitzii, Araucaria angustifolia and Sebastiania commersoniana were stood out, respectively, in hillside environment, open and humid forest. It was observed that the individuals' presence with smaller diameter will guarantee the permanence of these species for a medium period. It is ended that interventions silviculturais in this ecosystem consider the presence of different groupings, characterized by environment and specific species.

<b>Determination and validation of group numbers in a cluster analysis: A case study applied to forestry science

“…Based on the cophenetic correlations of hierarchical clustering methods presented (Table 1), the method of average linkage provided better grouping, as it presented the highest cophenetic correlation (0.89), which was expected because the method of average distances produced better partitions than the single linkage, complete linkage and Ward's methods. It has been observed that Ward's method (0.39) provided the worst group, as it presented the smallest cophenetic correlation, which is in agreement with Barroso and Artes (2003) and Araujo, Chamil, Lonhhil, Avila, & Brena (2010), who also found similar results with the same methods but different species. Comparing is hierarchical methods (Table 1).…”

Vascular epiphytic flora of a high montane environment of Brazilian Atlantic Forest: composition and floristic relationships with other ombrophilous forests

“…Therefore, species like A. angustifolia and P. lambertii, which are dominant trees in the studied area (Santana 2016), often emphasised among the species of the prominent importance value index in phytosociological studies conducted on MOF of the Southern and Southeastern regions (Geraldi et al 2005;Seger et al 2005;Ribeiro et al 2007;Araujo et al 2010;Silva et al 2012;Souza et al 2012), can possibly be a determinant for the occurrence of epiphytic species shared by areas with this physiognomy, regardless of geographic distance or environmental variables. Wilberger et al (2009) andFurtado &Menini Neto (2015a) evaluated the vascular epiphytes on A. angustifolia and P. lambertii, respectively, showing their importance as support for the epiphytic synusia.…”

Influência Dos Fatores Ambientais No Componente Arbóreo De Fragmentos Florestais Em São Francisco De Paula - Rio Grande Do Sul

“…Para a caracterização química e física do solo, foram coletadas três amostras simples de solo, na camada 0 a 20 cm, formando a amostra composta, em cada uma das 32 parcelas inventariadas. Foram realizadas análises químicas, conforme metodologia proposta por Tedesco et al (1995) (NAPPO et al, 2000;ARAUJO et al, 2010;SANTOS et al, 2012). Assim, os dados de entrada consistiram em uma matriz principal de densidade das espécies (indivíduos/parcela), com CAP ≥ 30 cm, composta por 32 parcelas (linhas) e 22 espécies (colunas), e uma matriz secundária com 32 parcelas (linhas) e 24 variáveis ambientais (colunas).…”