Browsing by Subject "Agent-based modeling smallholder agriculture"

Now showing 1 - 1 of 1

Agent-based modeling of human-environment interactions in a smallholder agricultural system in the Atlantic Forest (Ribeira Valley, SP, Brazil)
(2021) Munari, Lucia Chamlian; Berger, Thomas
Shifting cultivation systems (SCSs) have been practiced all over the tropics for centuries as the primary subsistence strategy for smallholders. However, since the mid-20th century, SCSs have been submitted to changes, driven by a combination of geographic, economic, socio-political, and demographic factors. Consequently, land use changes lead to agricultural intensification and the replacement of more profitable and permanent practices. The implementation of forest conservation policies (FCPs) is one of the changing drivers to SCSs. They have been designed to reduce or eliminate it, criminalize traditional practices, restrict resources access, displace locals, and increase inequalities and land conflicts. In Brazil, SCSs have been practiced by smallholders and indigenous groups, including Quilombolas, descendants of African enslaved who rebelled against the Portuguese regime. After the abolition of slavery, they remained spread over the country without any state legitimation. Their recognition and rights to ancestors land were possible only in 1988, with the Brazilian Constitution. The Ribeira Valley (Southeastern Brazil) is home to dozens of Quilombos, one of the most significant Atlantic Forest remnants, and high biodiversity. Its first Quilombos were formed in the 18th century and relied on SCS to survive, relatively isolated, up to the 1950s. However, in the context of SCS changes, Quilombos are under a transitional process in different dimensions, including constraints to their traditions by FCPs, generating conflicts. Inspired by this challenging scenario, the Thesis goals are to evaluate Quilombolas’ socioeconomic conditions and the perception of FCPs implementation and integrate two modeling tools. The tools will model the impact of agricultural transitions on family wealth, income, landscape structure, and tree community β diversity and model the impact of FCPs over the equal economic and ecological dimensions. Socioeconomic data were gathered in 2017 in 14 communities through interviews of 164 farmers. Quilombolas’ perception of FCPs and constraints for agricultural practice were investigated. The modeling implementation used MPMAS (Mathematical Programming-based Multi-Agent Systems) to simulate land use change in agriculture and forestry. MPMAS was integrated (through land use maps) with a Generalized Dissimilarity Modeling tool (GDM) to predict beta diversity as a function of environmental variation. The modeling exercise was implemented for Pedro Cubas territory, a Quilombo with 52 households located in Eldorado (SP). A combination of primary and secondary data from different sources was used, including a socioeconomic census of 2014 and a collection of tree data in 2016. Five economic/political scenarios were created for comparisons, with a baseline and four different counterfactual situations, varying in market access and FCPs versions. Seven yield curve scenarios and 30 Sobol’ repetitions were combined, totalizing 1050 simulations. A tradeoff analysis was applied over the political scenarios. MPMAS sensitivity/uncertainty analyses revealed variation on staples consumptions among yield curve scenarios, the sensitivity of income to different parameters, and each income source relevance. The GDM calibration highlighted the importance of climate predictors for tree species, indicating vulnerability to potential climate variability. Results revealed that only 32% of the families were practicing SCS in 2017, but it was still relevant for food security. 83% of the interviewees were unsatisfied with the FCPs, especially the timing of issuing the licenses for SCS. The political scenarios comparison indicates that agricultural intensification caused an improvement in average income. Still, it was accompanied by economic inequality, diminished rotation of plots, lower diversity of habitats, and a less permeable landscape structure (on fallows and because of the emergence of pasture and perennial areas). GDM results showed a significant change in landscape structure/tree community for at least 10% of the territory in the last decades. Regarding FCPs implementation, scenario comparison showed that well-being conditions improved when FCPs were excluded, although more ecological impacts occur. However, such effects refer to only 2.6% of the territory where 90% is covered by mature forest, and GDM indicates that the total ß diversity would not be significantly affected. The tradeoff analysis showed that FCPs are significant for conservation in the present context when perennials and pasture areas occur. In the isolated scenario case, when SCS is the only economic activity, a combination of good well-being and conservation performances was found, suggesting it is causing even lower environmental impacts. I recommend more flexible policies for SCS implementation in the Quilombos in general, for the potential of improving well-being conditions by impacting a small share of the territories. FCPs flexibilization would be even more relevant to the communities that don’t have access to alternatives to SCS.