Assessing the effects of agricultural intensification on natural habitats and biodiversity in Southern Amazonia

The following paragraphs briefly describe the central assumptions of the scenarios. For a comprehensive overview of the quantitative scenario assumptions (crop production, crop yield, population, and livestock) see [56]. An elaborate description and discussion of the trans- lation process from qualitative to quantitative information and the respective results for all sce- nario assumptions is described in Scho¨nenberg et al. [62]. The Trend scenario describes a growing demand for agrarian products based on an extrapo- lation of growth trends from 1973 to 2000 specific for each modelled crop. Furthermore, it is assumed that environmental policies like the Brazilian Forest Code or the Soy- and Cattle Moratorium will not be implemented. Only the illegal conversion of natural habitats (pro- tected areas) is prohibited due to good law enforcement. The technological development of agricultural practices in the study area includes an intensification of agricultural production through increasing crop yields. The possibility to intensify pasture management is not consid- ered in this scenario. Two intensification scenarios (Legal Intensification and Illegal Intensification) assume a growing demand for agrarian products (see Trend Scenario) further reinforced by population and GDP growth generated in Asian countries (as export markets). The technological develop- ments of agricultural practices in the study area include a high degree of agricultural intensifi- cation including the intensification of pasture management. Both scenarios presume the

intensification of cattle ranching. In PA, we assume an intensification rate of 4.5% per time step up to a maximum of 30%. That means that the biomass productivity of any pasture grid cell is increased by 4.5% until biomass productivity is 30% higher than in the base year. As agriculture in MT is presumed to be more mechanized, large scale, and world market oriented [63, 64], we assume an intensification rate of 9% up to a maximum value of 50%. These assumptions are based on observed pasture intensification rates in Brazil. According to Wint et al. [65] and Lapola et al. [17], the stocking density of pastures in Brazil rose continuously from 1990 to 2010, with a total increase of 45% during that period. The two scenarios vary in terms of environmental law enforcement. While the Legal Intensification scenario assumes compliance with environmental policies (environmental protected areas, Brazilian Forest Code), the Illegal Intensification scenario presumes noncompliance with environmental law expressed as the defiance of environmental protected areas concerning agricultural expansion and the noncompliance with the Brazilian Forest Code. This scenario assumes the possibility to convert land that is under conservation (e.g. nature reserves), thus opening up spaces that are not allowed for conversion in all other scenarios. The Sustainable Development scenario describes a new social model. This new model includes citizenship, an inclusive economic system, clear land tenure rights, and strong law

enforcement including participatory monitoring of deforestation. Furthermore, it portrays a substantial change in terms of anthropogenic consumption pattern, away from a meat oriented diet toward a healthy and sustainable diet as proposed by the WHO [66, 67] including further intensification of crop production. Moreover, the conversion of areas classified as covered by rainforest into agricultural area is not allowed according to the assumptions of the scenario. 2.4. Maps of vertebrate diversity and Biodiversity Intactness Index (BII) We use maps of vertebrate diversity covering the whole area of Brazil [5] to illustrate the over- lapping of areas of vertebrate diversity and simulated LULCC in each investigated scenario. The species diversity maps were generated by deriving polygon range data concerning birds from BirdLife International and NatureServe [68] and polygon range data concerning mam- mals and amphibians from the International Union for the Conservation of Nature [69]. These polygon range datasets were rendered at a spatial resolution of 10×10 km in order to PLOS ONE Agricultural intensification effects on natural habitats and biodiversity PLOS ONE | https://doi.org/10.1371/journal.pone.0225914 November 25, 2020 6 / 21