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).