No abstract

This study identifies the hotspots of land use cover change (LUCC) under two socioeconomic and climate change scenarios [business as usual (BAU) and a pessimistic scenario] at the national level for Mexico for three-time periods. Modelling suggests that by 2050 grassland and tropical evergreen forest will be the most endangered ecosystems, having lost 20-33% (BAU) or 43-46% (pessimistic scenario) of their extent in comparison to 1993. Agricultural expansion would be the major driver of LUCC, increasing from 24.4% of the country in 1993 to 30% (BAU) or 34% (pessimistic) in 2050. The most influential variables were distance from roads and human settlements, slope, aridity, and evapotranspiration. The hotspots of LUCC were influenced by environmental constraints and socioeconomic activities more than by climate change. These findings could be used to build proposals to reduce deforestation, including multiple feedbacks among urbanization, industrialization and food consumption.

Biomass burning, including fires, has been identified as the largest source of primary fine carbonaceous particles in the troposphere and one of the major drivers of global carbon (C) cycle, cloud properties, and climate. Most of the global C emissions happen in the Pantropic region. Modeling estimates suggest an increase in Mexican fire frequencies, intensity, and C emission to the atmosphere. However, no study has combined field and satellite data to estimate C emissions by fires for any tropical country. Here, we present an approach to estimate the spatiotemporal variability of fires and its total C emissions in Mexico with the associated climate that combines national fire inventories with remote sensing. We provide evidence that tropical ecosystems, particularly tropical forests at Yucatan Peninsula, Pacific Coast, and Gulf of Mexico, provide the largest C emissions with high fire densities. We found evidence to contrast the relationships of the interannual and intra-annual variability of C emissions with immediate and lagged climate effects such as El Niño and La Niña events. Data also indicate that C emissions from fires are up to 11 times higher than those from deforestation and account 19% of the total National CO 2 emissions and 5% of the total Pantropical C emissions. Because fires are related to climate change, we encourage future studies to focus on climate fire feedbacks for implementing adequate climate mitigation strategies.

Mexico is a biologically megadiverse country, but its biodiversity is endangered due to high deforestation rates. Impacts of land-use/cover-change and climate change are unevenly distributed, which hinders the execution of conservation practices. Consequently, an adequate spatial conservation prioritization is crucial to minimize the negative impacts on biodiversity. Global and national efforts to prioritize conservation show that >45% of Mexico should be protected. This study develops an applicable spatial conservation prioritization to minimize impacts on biodiversity, under three scenarios. They integrate exposure to land-use/cover-change and climate change scenarios, adaptive capacity to deal with the exposure, and the distribution of endemic species on risk of extinction. Our results show that by 2050 between 11.6%, 13.9% and 16.1% of Mexico would reach score ≥50 in vulnerability (VI), under the optimistic, BAU, and the worst-case scenarios, respectively. By 2070, these figures would rise to 11.9%, 14.8% and 18.4%. Amphibians are the most threatened vertebrates with 62.2% of endemic species being critically endangered or endangered, while 39.2%, 11.8%, and 8.5% of endemic mammals, birds and reptiles are endangered or critically endangered. The distribution of these amphibians accounts for 3.3% of the country's area, while mammals, birds, and reptiles represent 9.9%, 16.2%, and 28.7% of Mexico. Moreover, seven municipalities (0.39% of the country) represent 30% of the most vulnerable areas (VI=70). This study offers relevant information at the levels of municipality and species to help decision-makers prioritize national efforts for the conservation of ecosystems and biodiversity under land-use/cover and climate change. This study is replicable in other regions which aim to adapt decision-making and land management for biodiversity conservation.