Padrões espaciais de Qualea grandiflora Mart. em fragmentos de cerrado no estado de São Paulo

Costa, Rafael Carvalho da; Santos, Flávio Antonio Maës dos

doi:10.1590/s0102-33062011000100025

Cited by 7 publications

(13 citation statements)

References 28 publications

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“…In this case, when comparing fire protected and unprotected fragments, spatial aggregation should be lower in intensity and larger in scale of aggregation (size of clumps) in fire protected fragments. In a study of spatial patterns of Q. grandiflora in fire-protected and unprotected Cerrado fragments, Costa & Santos (2011) found results contrary to this expectation: in fire-prone fragments the intensity was equal to or lower than, and the scale of aggregation was similar to, that found in fireprotected fragments.…”

Section: Discussionmentioning

confidence: 74%

Spatial patterns of two co-occurring savanna and forest tree species in a dense fire-protected savanna fragment

Costa

Santos

2016

Acta Bot. Bras.

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Savanna-forest transition under fi re-exclusion could be explained by diff erential competitive performance of savanna and forest species under shading/fi re-exclusion. Aiming to understand strategies related to either habitat affi nity, we investigated spatial patterns of a savanna and a forest species in a fi re-protected savanna. We predicted that: savanna species would have lower abundance than the forest species due to a restriction in the number of open microsites; segregation of size classes and a trend from clumping to regularity with size for forest species due to absence of microsite limitation and intra-specifc competition; and spatial association and increasing clustering with size for savanna species due to microsite limitation. To test these predictions, we described spatial patterns of plants in two size classes in three plots of 0.5 ha. We analyzed spatial patterns and associations of size classes using SADIE methodology. Diff erent from what we expected, both species were more abundant among the studied plots and exhibited an increasing aggregation from small to large size classes. We also found a positive spatial association between size classes of both. Th ese results suggest that both savanna and forest species produce similar spatial patterns independently of habitat affi nity. We discuss the possible processes responsible for the observed patterns.

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Section: Discussionmentioning

confidence: 74%

Spatial patterns of two co-occurring savanna and forest tree species in a dense fire-protected savanna fragment

Costa

Santos

2016

Acta Bot. Bras.

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“…However, other studies in those same regions – tropical rain (Hubbell ) and seasonally dry forests (Hay et al . ; Costa & Santos ) – have reported the aggregation of adults in some tree species to be greater than that found in the initial stages, contradicting the general pattern. In these cases, DDM does not explain the spatial pattern, and the increased aggregation of adults has been attributed to density‐independent mechanisms, such as asexual propagation (Pare et al .…”

Section: Introductionmentioning

confidence: 87%

Is the spatial pattern of a tree population in a seasonally dry tropical climate explained by density‐dependent mortality?

et al. 2017

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Spatial pattern of tropical plants is initially generated by limited seed dispersal, but the role of density-dependent and independent mechanisms as modifiers of these patterns across ontogeny is poorly understood. We investigated whether density-dependent mortality (DDM) and environmental heterogeneity can drive spatial pattern across the ontogeny of a tree in a seasonally dry tropical climate. We used Moran's I correlograms and spatial analysis by distance indices (SADIE) to assess the spatial patterns of the pre-and post-germinative stages of Cordia oncocalyx (Boraginaceae), an abundant tree endemic in the deciduous thorny woodland in the northeastern Brazilian semiarid region. We also used RDA to analyse the effect of DDM and environmental heterogeneity (measured by microtopography and canopy openness) in the mortality and recruitment. Seeds, seedlings, juveniles and adults showed aggregated spatial patterns; infants and immatures were randomly distributed; adults, seeds and seedlings attracted each other while adult, juveniles and immatures repulsed each other. Infant and seedling mortality rates were related to DDM and the recruitment from infant to juvenile was more influenced by spatial heterogeneity. Attraction was determined by local dispersal; repulsion was related to DDM and environment heterogeneity, which allowed the return to aggregation in adult stage. Together, these results indicated that spatial pattern can change across ontogeny, in which the initial stages are responsive to DDM and the final stages are influenced by spatial heterogeneity.

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“…Pode-se então avaliar a presença de autocorrelação positiva ou negativa entre as unidades amostrais, a partir de diversas classes de distâncias, gerando assim um correlograma para a espécie (Rosenberg & Anderson 2011). No presente estudo, foram definidas 10 classes de distância com intervalos crescentes de 10 metros, valor correspondente à largura mínima entre unidades amostrais (Costa & Santos 2011). Cada correlograma gerou respectivos valores de índice I de Moran, de acordo com a classe de distância analisada, variando de -1 a 1, sendo cada valor verificado quanto à significância por meio da correção de Bonferroni para comparações múltiplas (Legendre & Legendre 1998;Rosenberg & Anderson 2011).…”

Section: Análise Dos Dadosunclassified

“…Os índices obtidos pelos correlogramas em cada classe de distância foram finalmente comparados aos gráficos de superfície gerados a partir da análise de distribuição espacial, de modo a observar as escalas de agregação, segregação e aleatoriedade que ocorreram entre unidades amostrais (Costa & Santos 2011), permitindo uma análise mais acurada da distribuição de abundâncias em determinadas escalas (McIntire & Fajardo 2009). …”

Section: Análise Dos Dadosunclassified

Padrões espaciais e ecológicos de espécies arbóreas refletem a estrutura em mosaicos de uma floresta subtropical

et al. 2012

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RESUMO(Padrões espaciais e ecológicos de espécies arbóreas refletem a estrutura em mosaicos de uma floresta subtropical). A abundância e distribuição espacial das espécies podem ser reflexos das necessidades do seu nicho ecológico, além de reflexos das variações ambientais no tempo e espaço. Os objetivos do presente trabalho foram analisar a distribuição espacial e grupos ecológicos das espécies arbóreas em um remanescente de floresta subtropical e avaliar a interferência destes padrões sobre métricas de riqueza e diversidade. Os padrões espaciais foram avaliados considerando uma área amostral de 1 ha dividida em unidades amostrais contíguas de 10 x 10 m, onde todos os indivíduos com perímetro à altura do peito ≥ 15 cm foram amostrados. A descrição dos padrões foi obtida por meio de correlogramas (índice I de Moran), considerando diversas classes de distância, índices de agregação e diagramas de superfície. A co-ocorrência entre espécies foi analisada por meio de índices de associação espacial. A maioria das espécies apresentou distribuição agrupada e com autocorrelação espacial positiva, sobretudo para as menores classes de distância, indicando a formação de pequenos grupos de indivíduos. Da mesma forma, 17 espécies apresentaram associações espaciais (co--ocorrências), formando densos agrupamentos e, embora não tenham interferido sobre a riqueza específica, Casearia sylvestris e Ocotea diospyrifolia diminuíram a equabilidade em alguns setores da área. Espécies tolerantes à sombra apresentaram-se associadas, bem como, espécies dependentes de luz, indicando que a dinâmica de mosaicos pode interferir diretamente sobre a distribuição das espécies, sobretudo pela limitação de dispersão.Palavras-chave: autocorrelação espacial, correlogramas, índices de distância, limitação de dispersão, riqueza de espécies ABSTRACT (Spatial and ecological patterns of tree species reflect patch dynamics of a subtropical forest). The abundance and spatial distribution of species may reflect on niche requirements, interactions among individuals and across as time and space. In this way, the aims of this work were to analyze tree species distribution and ecological groups in a remnant of subtropical forest to evaluate the interference of such patterns over richness and diversity metrics. We evaluated the spatial patterns of a 1 ha area divided into 10 x 10 m sampling units where we surveyed all living trees with perimeter at breast height ≥ 15 cm. Pattern descriptions were obtained by using correlograms (Moran's I) over several distance classes, aggregation indices and surface diagrams. The co-occurrence among species was obtained by using spatial association indices. Furthermore, 17 species showed aggregated distribution and positive spatial autocorrelation, mainly in the shorter distance classes, which indicated the occurrence of several small groups of individuals. In addition, many species were spatially associated with dense groups and although such groups do not influence species richness, Casearia sylvestris and Ocotea diospyrifol...

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Padrões espaciais de Qualea grandiflora Mart. em fragmentos de cerrado no estado de São Paulo

Cited by 7 publications

References 28 publications

Spatial patterns of two co-occurring savanna and forest tree species in a dense fire-protected savanna fragment

Spatial patterns of two co-occurring savanna and forest tree species in a dense fire-protected savanna fragment

Is the spatial pattern of a tree population in a seasonally dry tropical climate explained by density‐dependent mortality?

Padrões espaciais e ecológicos de espécies arbóreas refletem a estrutura em mosaicos de uma floresta subtropical

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