Análise de persistência do estado da vegetação usando NDVI na bacia do Rio Itapemirim-ES

Abstract

Resilience is a fundamental concept to understanding vegetation as dynamic component of the climate system. Complementarily, it expresses the ecosystem capacity to tolerate disturbances and recover its initial state. To associate resilience with agriculture production and pasture and forest preservation represents a socio-economical challenge to the Brazilian agriculture and livestock. In particular, this work focused on coffee crops and pasture fields. The objective was to perform an analysis of the evolution of the vegetation of the Itapemirim river basin throughout the years from 2000 to 2015 to evaluate the persistence and degree of vulnerability of the vegetation status with the support of satellite monitoring. NDVI defined by a 16-day composition product based on MODIS images was employed. The proposed approach evaluated negative and positive trends in the vegetation growth, which allowed to classifying such pattern behavior as persistent or not. In addition, the probabilities related to a defined persistence along time are calculated, jointly with the average lifetime for the decay of that probability. It is expected for healthy vegetation that the mean value of time for positive persistences is higher than the one for negative persistence values, which is the predominant result identified in the basin. Coffee crop presented positive decay well above the negative, which, in contrast to the average for the basin, indicated healthy vegetation. On the other hand, pasture analysis showed that there is a tendency of degradation of this type of soil use, highlighting lower resilience capacity.