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

decreased by 43% compared to the Trend Scenario. Also in both cases, the affected distribution ranges of vertebrate species could be reduced considerably. These results suggest that intensifi- cation measures are effective. This is confirmed by Strassburg and Latawiec who found in their study of possible future agricultural productivity scenarios that an increase of pasture produc- tivity to 49–52% of its potential productivity in Brazil would suffice for the projected increase of agricultural production without further appropriation of natural habitats [84]. Although, the effect of combined intensification and adequate conservation policies can contribute stron- ger to the preservation of the assessed vertebrate species as the results of the Legal Intensifica- tion Scenario (see Section 2.3) show. This can be confirmed by Sparovek et al. who indicate that in all of their simulated future land use scenarios, effective conservation policies played the most important role in conserving natural habitats [85]. Further, the effective protection and conservation of forested land will not impair Brazil´s ability to produce agricultural ressources for demanding markets in the near future as has been confirmed by de Souza Fer- reira Filho et al. [86]. This picture is confirmed in PA. Here, the amount of converted natural habitats could be limited by 43% (Legal Intensification Scenario) and by 3% in the case of the Illegal Intensification Scenario. Despite this relatively low reduction of converted natural habi-

tats in the latter case, this simulated decrease still led to a considerable reduction of afflicted distribution ranges of vertebrate species due to a spatial shift of habitat conversions away from the distribution ranges of the investigated vertebrate species. Concerning the Sustainable Development Scenario in MT, cropland area expands especially strong due to a shift of anthro- pogenic consumption patterns away from meat toward crop intake while there is only a slight release of pasture area. Therefore, the decrease of pasture area can only partially counteract the expansion of cropland, and thus the loss of natural habitat area in MT remains relatively high compared to the situation in PA. This is also expressed in the reduction of affected distribution ranges. The simulated relocation of cropland onto released pasture area in PA almost completely prevents the loss of natural habitats that are known distribution ranges of the inves- tigated vertebrate species. This development is confirmed by Alkimim et al. who found that 50 million hectares of pasture land in Brazil are suitable for crop prodcution and thus, can spare forest area from conversion into agricultural land [87]. Especially here, the shift of human con- sumption toward a plant based diet is the key factor for limiting the loss of natural habitats resembling distribution ranges of vertebrate species as the intensification of pastures is not part of the assumptions for the Sustainable Development Scenario. The optimal combination

of intensification and conservation measures as well as the interplay with changes of anthropo- genic consumption patterns with the goal of a maximized reduction of converted natural habi- tats depends on the present situation in the respective region. This is illustrated by the heterogeneity of conversions of natural habitats in PA and MT, under the respective scenario assumptions. 3.3. The combined impacts of expansion and intensification of agriculture on vertebrate diversity 3.3.1. Para´. The effects of a conversion of natural habitats on vertebrate species diversity are confirmed by our assessment of the BII in PA. Table 4 shows, the impact on species diver- sity, as expressed by changes of the BII, is strongest as calculated in the case of the Trend Sce- nario in PA. We found especially strong redcutions of BII for small-ranged amphibians, threatened mammals, followed by threatened amphibians and endemic mammal species. In the case of the Legal Intensification Scenario, we see BII value decreases for all taxa and categories. Espe- cially strong disturbances can be discerned in the case of small-ranged amphibian species, PLOS ONE Agricultural intensification effects on natural habitats and biodiversity PLOS ONE | https://doi.org/10.1371/journal.pone.0225914 November 25, 2020 12 / 21