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Universidade Federal do Rio Grande do Norte (UFRN) 2020

Padrões espaço-temporais da produtividade vegetal na Caatinga

Henrique, Fernanda Lamin

Titre : Padrões espaço-temporais da produtividade vegetal na Caatinga

Auteur : Henrique, Fernanda Lamin

Université de soutenance : Universidade Federal do Rio Grande do Norte (UFRN)

Grade : Mestrado em Ecologia 2020

Résumé
Ecosystem patterns of vegetation are well related to climatic factors in seasonal environments. Rainfall is a limiting resource in arid lands but there is evidence that in lack of precipitation, geographic aspects, such as terrain and water balance contribute to stabilizing primary productivity. Using geoprocessed data of temporal series, we tested the influence of altitude and water deficit for each vegetation type (forest, Grassland and water deficit) on primary productivity and on the stability of this ecosystem function in Caatinga domain. We expect a positive effect and a negative effect, respectively, on primary productivity and stability. We believe arborous physiognomies depend more on altitude increase while shrubby-herbaceous layers are more strongly by water deficit. We also classified Caatinga in higher and lower productivity and stability, based on median division. And, we modeled the temporal structure of these changes, seasonally, through a cross-correlation function. Water deficit was the main predictor of productivity and stability, affecting both negatively, while altitude had a positive effect, but not in forest vegetation. Forest, still, is the vegetation in which stability is most affected by water deficit, indicating that this ecosystem may be more prone to climate change. Primary productivity variation in Caatinga through months fluctuates seasonally, and the greater portion takes part in a synchronized cycle, suggesting vegetation dynamics is predictable even with rainfall irregularities. Understand how these patterns vary in the landscape and what is the role of environmental fluctuations is important to conduct conservation efforts and understand what vegetation types may be more vulnerable to climate change.

Mots Clés  : Índice de vegetação ; Caatinga ; Estabilidade ecossistêmica ; Estresse hídrico ; Geoprocessamento

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Page publiée le 8 décembre 2020