RESUMO
BACKGROUND: Solanum sisymbriifolium is a native plant of South America introduced into Africa, which has detrimental effects on crop yields, and on the environment due to weed control treatment by burning. In South America, S. sisymbriifolium is naturally controlled by the beetle Gratiana spadicea, making this a potential option for its control in Africa. Here, we aim to generate current and future scenarios for the introduction of G. spadicea as a biocontrol agent in Africa, analysing: (i) current and future effective biocontrol areas; (ii) potentially avoided economic losses (AEL), and chemical control costs and savings; and (iii) avoided carbon emissions (ACE) associated with the non-burning of crop fields. We combine species distribution models (SDM) with land cover maps to estimate current and future effective biocontrol considering Representative Concentration Pathways (RCP) 4.5 and 8.5 climate change scenarios. We then estimate AEL and ACE using biocontrol, and chemical control costs and savings. RESULTS: The effective biocontrol area reached 392 405 km2 in 18 countries, representing 40% of potentially affected croplands. Climate change induced a decrease in affected croplands and effective biocontrol. The estimated AEL reached US$45 447.2 ± 5617.3 billion distributed across 16 countries, while the estimated chemical control costs and savings reached US$1988.5 billion and 1411.8 billion, respectively. Potential ACE reached 36.3 ± 5.4 Tg. CONCLUSIONS: Our study provides evidence for the potential benefits of biological controllers on economic losses and carbon emissions, which can be incorporated into sustainable development in low-income countries.
Assuntos
Solanum , África , Agricultura , Carbono , Mudança ClimáticaRESUMO
BACKGROUND: The insect Bagrada hilaris (Burmeister) an important pest worldwide, mainly due to the serious economic losses incurred and the large number of zones invaded. However, current and future spatial distributions of this pest, and the total area of cropland potentially affected have not been estimated. Here, we aim to: (1) estimate the potential geographic distribution of B. hilaris; (2) quantify the total area of cropland potentially affected worldwide, and in two recently colonized zones (California and Chile); and (3) estimate future changes in distribution under different climate change scenarios. RESULTS: We found that B. hilaris shows high environmental suitability in Mediterranean and arid regions, potentially affecting 1 108 184.1 km2 of cropland worldwide. The most affected continents were Asia and America, with 309 659.8 and 294 638.6 km2 of cropland at risk. More than 50% of cropland areas are at risk in seven countries. In California and central Chile, 43.7% and 50% of susceptible crops are at a high level of risk, respectively. Climate change scenarios predict an increase in the potential distribution of B. hilaris worldwide; America being the most affected continent. CONCLUSIONS: Our results provide a spatially explicit baseline from which to focus efforts on the prevention, management and control of this pest worldwide. © 2018 Society of Chemical Industry.