Leaf area index of Caatinga biome and its relationship with hydrological and spectral variables
2019
de Almeida, Cicero Lima | de Carvalho, Thayslan Renato Anchiêta | Araújo, José Carlos de
Leaf area index (LAI) influences hydrological processes as both active and passive agents. In the Caatinga biome, little is known about LAI and its relationship with hydrological variables. Thus, the objective of this work was to measure LAI for a preserved arboreal-shrub vegetation and correlate it with hydrological variables (precipitation, evapotranspiration and soil moisture) and spectral (vegetation indices) in order to evaluate and to monitor their dynamics in time and space. The experiment was carried out in the Aiuaba Experimental Basin, considering three soil-vegetation associations and two periods (dry and rainy seasons) for three years (2014–2016). The results showed that LAI maximum is influenced by the type of soil-vegetation association and does not change over time. Among the hydrological variables, all had a significant correlation with LAI, but the best result was obtained using soil moisture. The best performance among the vegetation indexes for LAI estimation of the preserved Caatinga shrub-arboreal area was the Enhanced Vegetation Index (EVI), as shown by the analyses. The presence of clouds during the rainy season prevented a better evaluation of LAI with vegetation index. We concluded that the LAI of a preserved arboreal shrub area in Caatinga (3.5 ± 1.3 m² m⁻²) can be monitored utilizing only precipitation, the precipitation-to-potential evapotranspiration ratio and soil moisture.
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