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The role of river morphodynamic disturbance and groundwater hydrology as driving factors of riparian landscape patterns in mediterranean rivers
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Orientador(es)
Resumo(s)
Fluvial disturbances, especially floods and droughts, are the main drivers of the
successional patterns of riparian vegetation. Those disturbances control the riparian
landscape dynamics through the direct interaction between flow and vegetation. The
main aim of this work is to investigate the specific paths by which fluvial disturbances,
distributed by its components of groundwater hydrology (grndh) and morphodynamic
disturbance (mrphd), drive riparian landscape patterns as characterized by the location
(position in the river corridor) and shape (physical form of the patch) of vegetation
patches in Mediterranean rivers. Specifically, this work assesses how the different
components of fluvial disturbances affect these features in general and particularly in
each succession phase of riparian vegetation. grndh and mrphd were defined by time
and intensity weighted indexes calculated, respectively, from the mean annual water
table elevations and the annual maximum instantaneous discharge shear stresses of
the previous decade. The interactions between riparian landscape features and fluvial
disturbances were assessed by confirmatory factor analysis using structural equation
modeling. Two hypothetical models for patch location and shape were conceptualized
and tested against empirical data collected from 220 patches at four different study
sites. Both models were successfully fitted, meaning that they adequately depicted
the relationships between the variables. Furthermore, the models achieved a good
adjustment for the observed data, based on the evaluation of several approximate fit
indexes. The patch location model explained approximately 80% of the patch location
variability, demonstrating that the location of the riparian patches is primarily driven by
grndh, while the mrphd had very little effect on this feature. In a multigroup analysis
regarding the succession phases of riparian vegetation, the fitted model explained more
than 68% of the variance of the data, confirming the results of the general model.
The patch shape model explained nearly 13% of the patch shape variability, in which the disturbances came to have less influence on driving this feature. However, grndh
continues to be the primary driver of riparian vegetation between the two disturbance
factors, despite the proportional increase of the mrphd effect to approximately a third of
the grndh effect
Descrição
Original Research
Palavras-chave
riparian vegetation riparian drivers fluvial disturbances Mediterranean confirmatory factor analysis
Contexto Educativo
Citação
Rivaes R, Pinheiro AN, Egger G and Ferreira T (2017) The Role of River Morphodynamic Disturbance and Groundwater Hydrology As Driving Factors of Riparian Landscape Patterns in Mediterranean Rivers. Front. Plant Sci. 8:1612.
Editora
Valentí Rull (ed.)