Fire Recurrence and Normalized Difference Vegetation Index (NDVI) Dynamics in Brazilian Savanna

Abstract

Fire is one of the main modeling agents of savanna ecosystems, affecting their distribution, physiognomy and species diversity. Changes in the natural fire regime on savannas cause disturbances in the structural characteristics of vegetation. Theses disturbances can be effectively monitored by time series of remote sensing data in different terrestrial ecosystems such as savannas. This study used trend analysis in NDVI (Normalized Difference Vegetation Index)-MODIS (Moderate Resolution Imaging Spectroradiometer) time series to evaluate the influence of different fire recurrences on vegetation phenology of the Brazilian savanna in the period from 2001 to 2016. The trend analysis indicated several factors responsible for changes in vegetation: (a) The absence of fire in savanna phytophysiognomies causes a constant increase in MODIS-NDVI, ranging from 0.001 to 0.002 per year, the moderate presence of fire in these areas does not cause significant changes, while the high recurrence results in decreases of MODIS-NDVI, ranging from −0.002 to −0.008 per year; (b) Forest areas showed a high decrease in NDVI, reaching up to −0.009 MODIS-NDVI per year, but not related to fire recurrence, indicating the high degradation of these phytophysiognomies; (c) Changes in vegetation are highly connected to the protection status of the area, such as areas of integral protection or sustainable use, and consequently their conservation status. Areas with greater vegetation conservation had more than 70% of positive changes in pixels with significant tendencies. Absence or presence of fire are the main agents of vegetation change in areas with lower anthropic influence. These results reinforce the need for a suitable fire management policy for the different types of Cerrado phytophysiognomies, in addition to highlighting the efficiency of remote sensing time series for evaluation of vegetation phenology.

Geobotanical Study of the Microforests of Juniperus oxycedrus subsp. badia in the Central and Southern Iberian Peninsula

“…The different groups of communities proposed for the Luso-Extremaduran province occupy areas whose dominant ecological factor is the xericity of the substrate. These are edaphoxerophilous formations with a permanent character that occupy restricted areas, but are currently in expansion, as frequent fires and the deforestation and clearing of the scrub layer have led to an extension of eroded areas due to soil loss: indeed, the absence or presence of fire is the main agent of vegetation change in areas with low anthropic influence [55]. These biotopes do not tend to be occupied by Fagaceae, and the forests of Quercus ilex subsp.…”

Fire regime of peatlands in the Angolan Highlands

“…The MODIS MOD13Q1.006 Terra Vegetation Indices 16-Day Global (Didan, 2015 ) was used to calculate the Normalised Difference Vegetation Index (NDVI) for the time-period 01/01/2001 to 31/12/2020, corresponding to the fire data archive. NDVI is a widely used index for detecting fire risk potential (Michael et al, 2021 ), fire recurrence (Santana, 2018 ) and fire recovery (João et al, 2018 ; Lacouture et al, 2020 ). The NDVI time-series are particularly useful for assessing the spatial and temporal dimensions of fire (Michael et al, 2021 ; Santana, 2018 ).…”

“…NDVI is a widely used index for detecting fire risk potential (Michael et al, 2021 ), fire recurrence (Santana, 2018 ) and fire recovery (João et al, 2018 ; Lacouture et al, 2020 ). The NDVI time-series are particularly useful for assessing the spatial and temporal dimensions of fire (Michael et al, 2021 ; Santana, 2018 ). The MOD13Q1 V6 product provides a vegetation index value per pixel, with a 250 m resolution (Didan, 2015 ).…”

Mapeamento Dos Incêndimapeamento Dos Incêndios Florestais No Bioma Pantanal E Bacia Do Alto Paraguai Entre 2018 E 2019os Florestais No Bioma Pantanal E Bacia Do Alto Paraguai Entre 2018 E 2019

“…Após a década de 70, na região pantaneira houve expansão da pecuária extensiva, cujo manejo fundamenta-se em uso intenso de mecanização, desmatamento e queima de biomassa para o aumento das áreas de pastagens provocando alterações de alinhamento dos rios, defasagem quanto ao período de inundação, erosões do solo, aumento dos incêndios orestais e focos de calor (Alvarado et al, 2017;Santana, 2018;Oliveira-Júnior et al, 2020).…”