Modelling land cover change in the Brazilian Amazon: temporal changes in drivers and calibration issues

Abstract

Land cover change (LCC) models are used in many studies of human impacts on the environment, but knowing how well these models predict observed changes in the landscape is a challenge. We used nearly three decades of LCC maps to run several LCC simulations to: (1) determine which parameters associated with drivers of LCC (e.g. roads) get selected for which transition (forest to deforested, regeneration to deforested or deforested to regeneration); (2) investigate how the parameter values vary through time with respect to the different activities (e.g. farming); and (3) quantify the influence of choosing a particular time period for model calibration and validation on the performance of LCC models. We found that deforestation of primary forests tends to occur along roads (included in 95 % of models) and outside protected areas (included in all models), reflecting farming establishment. Regeneration tends to occur far from roads (included in 78 % of the models) and inside protected areas (included in 38 % of the models), reflecting the processes of land abandonment. Our temporal analysis of model parameters revealed a degree of variation through time (e.g. effectiveness of protected areas rose by 73 %, p < 0.001), but for the majority of parameters there was no significant trend. The degree to which model predictions agreed with observed change was heavily dependent on the year used for calibration (p < 0.001). The next generation of LCC models may need to embed trends in parameter values to allow the processes determining LCC to change through time and exert their influence on model predictions.

Analyzing the Spatial Dynamics of Deforestation in Brazilian Amazon

“…The presence of spatial correlation reinforces that deforestation is related to local characteristics, that is, there are near regions where deforestation occurs with higher frequency. This conclusion is supported by the findings in Rosa et al () and Rosa et al (), that the deforestation presents a contagious process, mainly where there are roads near.…”

Balancing economic costs and ecological outcomes of passive and active restoration in agricultural landscapes: the case of Brazil

“…) and in the Amazon (Rosa et al . ) have shown considerable increases in native forest cover due to passive restoration. For instance, Ferraz et al .…”

Global MODIS Fraction of Green Vegetation Cover for Monitoring Abrupt and Gradual Vegetation Changes

“…Observing the Brazilian pixel temporal profile between 2003 and 2006, the FCover values decrease slowly at the beginning, and this could be attributed to logging activities, while at a certain point, this process seems to have an acceleration (end of 2005) that brings the cover percentage to less than 0.1 (from a value of approximately 0.5). This very rapid change in vegetation extent corresponds to a well-known strategy of clearing forest areas to be replaced with pastures for cattle [75]. After 2006, the FCover values suggest that other vegetation types, in this case, a mixture of cropland and pastures, replaced the tropical rainforest.…”