86 resultados para Spatial variation


Relevância:

60.00% 60.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Soil CO2 efflux is the primary source of CO2 emissions from terrestrial ecosystems to the atmosphere. The rates of this flux vary in time and space producing hot moments (sudden temporal high fluxes) and hot spots (spatially defined high fluxes), but these high reaction rates are rarely studied in conjunction with each other. We studied temporal and spatial variation of soil CO2 efflux in a water-limited Mediterranean ecosystem in Baja California, Mexico. Soil CO2 efflux increased 522% during a hot moment after rewetting of soils following dry summer months. Monthly precipitation was the primary driver of the seasonal trend of soil CO2 efflux (including the hot moment) and through changes in soil volumetric water content (VWC) it influenced the relationship between CO2 efflux and soil temperature. Geostatistical analyses showed that the spatial dependence of soil CO2 efflux changed between two contrasting seasons (dry and wet). During the dry season high soil VWC was associated with high soil CO2 efflux, and during the wet season the emergence of a hot spot of soil CO2 efflux was associated with higher root biomass and leaf area index. These results suggest that sampling designs should accommodate for changes in spatial dependence of measured variables. The spatio-temporal relationships identified in this study are arguably different from temperate ecosystems where the majority of soil CO2 efflux research has been done. This study provides evidence of the complexity of the mechanisms controlling the spatio-temporal variability of soil CO2 efflux in water-limited ecosystems. (C) 2014 Elsevier Ltd. All rights reserved.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The present study aimed to analyze the floristic and structural descriptors of tree species natural regeneration in a forest sector with synchronized bamboo (Merostachys multiramea Hackel) die-off (CT) and an adjacent area with continuous canopy cover (ST) in an araucaria forest fragment in the municipality of Lages, Santa Catarina state. A total of 14, 5x5m, plots (six plots in CT sector and eight in ST sector) were allocated, where all tree species regenerative individual with circumference at breast height smaller than 15cm and height higher than 25cm was measured (diameter at soil level) and identified. The richest families were: Myrtaceae (nine), Solanaceae (six) and Aquifoliaceae (four). The Shannon Diversity Index in ST and CT sectors were respectively 2.73 and 2.31. The species with the highest importance values in CT sector were Solanum variabile, Piptocarpha angustifolia, Mimosa scabrella, Jacaranda puberula and Solanum pseudoquina. In ST sector, the species with highest importance values were Myrsine lorentziana, Casearia decandra, Cinnamodendron dinisii, Drimys brasiliensis and Ilex paraguariensis. The results showed that the synchronized bamboo die-off influenced the spatial variation in the floristic and structural descriptors of the tree species natural regeneration.

Relevância:

60.00% 60.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

60.00% 60.00%

Publicador:

Resumo:

The relationships between the spatial and temporal variations in the abundance of the shrimp Nematopalaemon schmitti and water temperature, salinity, and texture and organic-matter content of the sediment, were analysed in Ubatumirim, Ubatuba and Mar Virado bays on the northern coast of São Paulo, Brazil. Sampling was carried out monthly, from January 1998 through December 1999, from a shrimp boat equipped with double-rig nets, along six transects in each bay. In total, 2 116 specimens of N. schmitti were caught. Their distribution differed among bays, transects and seasons (ANOVA, p < 0.05). Highest total abundance was found in areas of high organicmatter content, in substrate composed mainly of very fine sand and silt and clay, and during winter and autumn. Although multiple regression analysis showed no significant relationship (p > 0.05), observations suggest that water tempera ture, sediment texture, organic-matter content, and the presence of biodetritus and plant fragments, provided favourable environmental conditions for the establishment of N. schmitti in the region.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Este trabalho teve como objetivo avaliar a influência das formas do relevo na variabilidade espacial de atributos físicos e suas relações com a mineralogia da argila de um Latossolo Vermelho eutroférrico, utilizando a técnica da geoestatística. Os solos foram amostrados nos pontos de cruzamento de uma malha, com intervalos regulares de 10 m, nas profundidades de 0,0-0,2 m, 0,2-0,4 m e 0,4-0,6 m para os atributos físicos e 0,6-0,8 m para os atributos mineralógicos. Os valores médios para a densidade do solo e resistência do solo à penetração são maiores no compartimento I onde a relação Ct/Ct+Gb é relativamente maior, indicando a presença de maior teor de caulinita. No compartimento II a condutividade hidráulica e a macroporsidade são maiores, influenciados provavelmente pelo predomínio da gibbsita. Portanto, conclui-se que a identificação das pedoformas é muito eficiente para compreender a variabilidade espacial de propriedades do solo. Sendo que, as variações na forma da paisagem promovem variabilidade espacial diferenciada das propriedades físicas e mineralógicas do solo.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Geographic differentiation and sexual dimorphism in eighteen morphometric characters of Lutosa brasiliensis (Orthoptera: Henicidae) collected in eight localities of the State of São Paulo (Brazil) were analysed. A two-way Multivariate Analysis of Variance (MONOVA) was used to assess simultaneously the effects of sex and geographic location (plus their interaction) on morphometric variability. The spatial patterns of variation were analysed by Factor and Spatial Autocorrelation Analyses (Moran's I coefficient in four distance classes). Both indicate that the main direction of variation is, for males and females, a north-south cline in overall body size. In females, however, ovipositor length is not correlated with overall body size and displays a different pattern of variation over geographic space, indicating that distinct evolutionary forces produced the geographic differentiation in the species.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Spatial patterns of morphometric variation in Apis cerana indica were analysed. Factor and spatial autocorrelation analyses were applied to 29 characters, measured in 17 populations in India. Correlograms showed that 15 characters are patterned geographically, and 13 of them are related to overall size. These characters are distributed as a north-south cline, probably reflecting adaptations to environmental conditions. However, the great number of characteristics without geographical pattern suggests that part of the morphometric variability is due to local stochastic divergences.

Relevância:

40.00% 40.00%

Publicador:

Resumo:

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)