RESULTS
Niche Modeling
Overall, we recorded 319 presences of A. microtis , 691 of C. thousand 271 of S. venaticus , throughout South America (Appendix-Figure 1 and Supplemental Material- Table S1). In general, our species niche distribution models reached adequate values for the Jaccard index (0.612 + 0.371; average + standard deviation), reaching higher predictive values than those that would be expected by chance. All models generated from the three species and the ranges of suitability of their respective algorithms are found in the Appendix (Figure 3).
Considering the final weighted ensemble for the three species (Figure 4), A. microtis in both current and future scenarios was more restricted to the western part of the Amazon Forest, including Colombia, Peru, Bolivia, but also in the northern part, including Venezuela, Suriname, Guyana, and French Guyana. However, we found that in the extreme northeast of the Brazilian Amazon, which includes the east of the state of Amapá and further north, in the south of Guyana near the northeast of the state of Roraima (Brazil), there are two spots of non-suitability for this species, which coincides with large patches of Brazilian savannah. When comparing the current and future distribution models, we observed a loss of 18.43% of the total A. microtisclimate suitability area in South America in the future. Of this total loss, about 15% is supposed to occur in the Brazilian Amazon. In this region, these losses are distributed in areas with high anthropic pressure, close to the southern limit of the Forest, in a transition zone with the Cerrado , in the states of Acre and Rondônia. However, we also observed areas of loss concentrated in the eastern borders of the species distribution, which are areas of high anthropic pressure in the Forest (Figure 4).
Cerdocyon thous has a high climatic suitability in open areas and anthropogenic landscapes, inside or outside the Amazon Biome, in both current and future scenarios. Its potential distribution within the Amazon natural savannahs in eastern Amapá state and part of Roraima state in northern Brazil. The species also shows suitability in anthropized areas in the southern limits of the Amazon region, and in the transition zone with the Cerrado Biome, especially in the states of Mato Grosso and Rondônia (Figure 4). In the current scenario, the area of ​​climatic suitability includes a strip in the northeast of the Brazilian Amazon, where high anthropogenic pressure is concentrated in the region. Outside the Amazon, this species also had climatic suitability for natural areas of Cerrado and anthropized open areas in the central-western, southeastern, and southern areas of Brazil east-central Bolivia, southeastern Paraguay, Uruguay, and northeast of Argentina. The future projected ensemble model predicts the loss of 56.54% of the C. thous climate suitability area across South America (Figure 4). About 88% of this total loss could occur in the Brazilian Amazon.
The projected area of climatic suitability for S. venaticus is almost as wide as for C. thous (Figure 4). However, the current distribution of S. venaticus includes both areas ofCerrado and dense forests, but also other Brazilian biomes and anthropogenic open areas (Figure 4). When we analyze the projection for the future, S. venaticus is the species that loses the most area with climatic suitability, among the three canids, with a reduction of 57.18% for all of South America. However, about 91% of this total loss will occur in the Brazilian Amazon (Figure 4).