Systematic review of soil ecosystem services in tropical regions.

Soil ecosystem service (SES) approaches evidence the importance of soil for human well-being, contribute to improving dialogue between science and decision-making and encourage the translation of scientific results into public policies. Herein, through systematic review, we assess the state of the art of SES approaches in tropical regions. Through this review, 41 publications were identified; while most of these studies considered SES, a lack of a consistent framework to define SES was apparent. Most studies measured soil natural capital and processes, while only three studies undertook monetary valuation. Although the number of publications increased (from 1 to 41), between 2001 and 2019, the total number of publications for tropical regions is still small. Countries with the largest number of publications were Brazil (n = 8), Colombia (n = 6) and Mexico (n = 4). This observation emphasizes an important knowledge gap pertaining to SES approaches and their link to tropical regions. With global momentum behind SES approaches, there is an opportunity to integrate SES approaches into policy and practice in tropical regions. The use of SES evaluation tools in tropical regions could transform how land use decisions are informed, mitigating soil degradation and protecting the ecosystems that soil underpins.

The importance of Legal Reserves for protecting the Pantanal biome and preventing agricultural losses.

Considering scenarios of future changes in land use have the potential to support policy-makers in drafting environmental laws to reconcile the demands of multiple land uses. The Pantanal, one of the largest wetlands in the world, has been undergoing rapid land use changes, and does not yet have any integrated environmental legislation on Legal Reserve for entire region (LR - minimum percentage of native vegetation required within private properties). The aim of this paper was to generate future vegetation loss scenarios for the Pantanal based on four LR values: (i) BAU: Business as usual, which considers existing laws: Native Vegetation Protection Law and State Decree; (ii) LRE: LR elimination owing to a bill recently proposed; (iii) LR50: which considers the bill proposing 50% of LR for the Pantanal; and (iv) LR80: our proposed levels of 80% of LR for the lowlands and 35% for the plateau (following values in the Amazon). Based on native vegetation loss from each scenario, we estimated the soil loss and sediment yield to rivers. Our results show that LRE would increase native vegetation loss in the Pantanal by as much as 139% when compared to the BAU, whereas increasing LR levels would reduce conversion values by 29% (LR80). Elimination of the LR would increase soil erosion and sediment production by up to 7% and 10%, respectively, compared to BAU. Based on native vegetation loss from each scenario, we estimated the soil loss and sediment yield to rivers with our data showing more than 90% of the sediment transported to the lowland originating from the plateau. The LR80 indicates a reduction in soil nutrient replacement costs of 10% compared to BAU, while in the LR50 these costs decrease by 1.5%, and in the LRE would increase of 8%. Our results show that abolishing current protections would have substantial impacts on avulsion processes, on several economic activities (tourism, fishery, cattle raising, etc.) and negative impacts for biodiversity conservation and would bring losses to agriculture in the Pantanal. Hence, our study brings clearly evidence of LR importance and need to expand it in this sensitive wetland.

Characterising the spatial distribution of opportunities and constraints for land sparing in Brazil.

Brazil is a megadiversity country with more tropical forest than any other, and is a leading agricultural producer. The technical potential to reconcile these roles by concentrating agriculture on existing farmland and sparing land for nature is well-established, but the spatial overlap of this potential with conservation priorities and institutional constraints remains poorly understood. We mapped conservation priorities, food production potential and socio-economic variables likely to influence the success of land sparing. Pasture occupies 70% of agricultural land but contributes ≤11% of the domestic food supply. Increasing yields on pasture would add little to Brazil's food supply but - if combined with concerted conservation and restoration policies - provides the greatest opportunities for reducing land demand. Our study illustrates a method for identifying municipalities where land-sparing policies are most likely to succeed, and those where further effort is needed to overcome constraints such as land tenure insecurity, lack of access to technical advice, labour constraints, and non-compliance with environmental law.