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

crop yields in Amazonia. It is important to note that this situation might occur until the mid or end of this century when changes in temperature and precipitation are projected to become more intense [95] with potentially stronger negative impacts on crop yields e.g. [94, 96]. 4. Conclusion Our results show that especially the potential for agricultural intensification in the Amazon may hint at the way of sustaining food production here [16] in addition to conserving natural habitats from conversion into managed land, thus preserving biodiversity. Moreover, it becomes obvious that especially the change of anthropogenic consumption habits can contrib- ute greatly to safeguard species diversity. This might look like a clear statement in favor of seg- regative agricultural approaches over integrative agricultural approaches. Segregative approaches focus on increasing agricultural production by an intensified management of agri- cultural production systems, thus conserving natural habitats from conversion into cropland or pastureland. On the contrary, integrative approaches focus on integrating agricultural pro- duction and biodiversity conservation for instance in the form of agroforestry. However, our results also draw a distressing picture of the future in regard to negative impacts of intensification measures [97]. Despite all the positives of an intensification of agri- cultural production concerning a conservation of natural habitats, the negative impacts of an intensified agriculture cannot be neglected. Especially pesticide, herbicide, and fertilizer appli-

cation have to increase in order to increase grass- and cropland productivity [98]. The increased application of agro-chemical products will have negative effects on biodiversity [97]. Especially the use of pesticides in tropical regions has strong negative effects on amphibian populations because they are more susceptible to pesticide use as compared to amphibian pop- ulations in temperate regions [99]. Therefore, biodiversity on intensified cropland is likely to decrease [100, 101]. Furthermore, the adoption of intensified agricultural production will be more capital-intensive. If the access to capital is a limiting factor, as might be the case for smallholder farmers, these producers might not be able to apply the required techniques and methods. This in turn will imperil their ability to stay competitive in comparison to large land holders who have better access to monetary resources and can make larger investments into the intensification of agricultural production [102]. Concluding, sufficient access to capital is required to introduce agricultural intensification on a broad scale. An increased livestock pro- duction in intensified systems (especially feedstock systems) will increase the demand for live- stock fodder production which, in turn, will induce an expansion of cropland area and may be a cause of additional deforestation [102]. Ultimately, future scenario studies will have to adapt a more holistic approach to the assess- ment of LULCC and agricultural management and its consequences for natural habitats and

biodiversity. Currently, this is done, on the one hand, by integrating mentioned organism groups, especially soil microorganisms, and by incorporating the aspects of functional diversity and functional redundancy. On the other hand, scenarios need to be, and will be, constructed with the help of approaches that focus on participatory methods in order to capture stake- holder knowledge as well as developments and drivers especially on local to regional scales thus, increasing the representativeness as well as communicability of results and recommendations. Author Contributions Conceptualization: Jan Go¨pel, Ru¨diger Schaldach. Formal analysis: Jan Go¨pel. PLOS ONE Agricultural intensification effects on natural habitats and biodiversity PLOS ONE | https://doi.org/10.1371/journal.pone.0225914 November 25, 2020 16 / 21