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

intensification of agricultural production, if it goes hand in hand with the protection of natural habitats, have the highest impact in terms of limiting the conversion of natural habitats, and thus, promoting the conservation of vertebrate species diversity. 3.2. Effects of natural habitat loss on the distribution ranges of vertebrate species 3.2.1. Para´. Fig 2 illustrates that the highest effect in terms of a distrubance of natural hab- itats and distribution ranges of vertebrate species in PA can be expected in case of the Trend Scenario. Allmost all of the 119,185 km2 of converted natural habitats in the case of the Trend Sce- nario is identified as a distribution range of bird and mammal species. Also, close to all of this coverted area is a ditribution range of endemic amphibians. Only the distribution ranges of small-ranged and threatened aphibians are not affected strongly by the conversion of natural habitats into managed land. 67,914 km2 of natural habitats were converted in the case of the Legal Intensification Sce- nario excluding 216,022 km2 of Legal Reserve as it remains in its original land-cover type “Rainforest”. The calculation of the area-weighted change of affected distribution ranges, including the Legal Reserve as it is considered affected by fragmentation, could be reduced by 46% for all mammal and bird categories. The afflicted distribution ranges could be decreased by 47% for endemic amphibians, by 45% for small-ranged and by 44% for threatened amphibi- ans compared to the situation in the Trend Scenario.

In the case of the Illegal Intensification Scenario, 114,608 km2 of natural habitat area is con- verted into managed land. In this case, the calculation of the area-weighted change shows a reduction of the affected distribution ranges by 40% for endemic bird and mammal species and by 38% for all other bird and mammal categories in comparison to the Trend Scenario. Also, the afflicted distribution ranges of endemic, small-ranged and threatened aphibians could be decreased by 46%, 31% and 37% respectively. The least negative effect on vertebrate species diversity due to a conversion of natural habi- tats is discernible in the case of the Sustainable Development Scenario. Not only the area of con- verted natrual habitats is less as compared to the other scenarios, also the share of this area that is a known habitat to vertebrate species is relatively low. The affected area known as Fig 2. Natural habitat area of investigated vertebrate species affected by conversion over total converted area in Para´. https://doi.org/10.1371/journal.pone.0225914.g002 PLOS ONE Agricultural intensification effects on natural habitats and biodiversity PLOS ONE | https://doi.org/10.1371/journal.pone.0225914 November 25, 2020 10 / 21