Canid collision—expanding populations of coyotes (Canis latrans) and crab-eating foxes (Cerdocyon thous) meet up in Panama

Abstract

The rise of the Panamanian Isthmus 3–4 million years ago enabled the first dispersal of mammals between North and South America in what is known as the Great American Biotic Interchange. Modern deforestation threatens the historic forest connectivity and creates new habitat for open-country species, as documented by recent expansions of North American coyotes (Canis latrans) and South American crab-eating foxes (Cerdocyon thous) into Central America. We used camera traps to map the expansions of these species into eastern Panama and found that, by 2015, coyote populations had colonized most agricultural area west of Lago Bayano. Most of our camera arrays east of this point documented crab-eating foxes, and evidence from roadkills showed some foxes had advanced farther west, but we never documented both species at the same camera-trap array, suggesting the possibility of fine-scale spatial avoidance. We used a data fusion approach to build species distribution models combining our camera surveys with records from the literature and roadkill. While the auxiliary data improved the predictive accuracy for both species, few clear habitat patterns emerged, which might reflect the generalist tendencies of these canids, or the fact that both are in the early stages of colonizing the region. Camera-trap photos showed that both species were nocturnal and revealed some dog-like morphology in coyotes, which could indicate their recent hybridization with dogs (Canis familiaris). Our continued monitoring of the Darién documented single coyotes moving through the western edge of the area in 2016 and 2018. This leaves only the great Darién forests between coyotes and South America. If deforestation continues in the region, these two invasive canids could represent the first of a new, Not-So-Great American Biotic Interchange, where generalist species adapted to human disturbance cross continents and threaten native biota.

Mapping the expansion of coyotes (Canis latrans) across North and Central America

“…If coyotes reach South America, it is likely that the grassland and agricultural habitats in Colombia and Venezuela could support viable populations, unless competition with native carnivores restricts them. Observations in eastern Panama suggests that road construction and agricultural development might facilitate coyote range expansion in previously forested tropical landscapes ( Méndez-Carvajal and Moreno 2014 , Hody 2016 ), but we find it improbable that coyotes would expand into intact parts of the Amazon rainforest. Conversely, we speculate that the open habitats of the Andes might offer suitable coyote habitat in such a scenario, and allow further expansion around the Amazon.…”

“…Coyotes rapidly expanded into deforested habitats in eastern Panama ( Méndez-Carvajal and Moreno 2014 , Hody 2016 ), and the dense forests of the Darién now represent the last major barrier between coyote populations and South American savannah ecosystems ( Hidalgo-Mihart et al 2004 , Méndez-Carvajal and Moreno 2014 ). However, this barrier may be more permeable than previously thought, especially along the coastlines, raising concerns that coyotes might reach South America in the near future ( Hody 2016 ). If coyotes reach South America, it is likely that the grassland and agricultural habitats in Colombia and Venezuela could support viable populations, unless competition with native carnivores restricts them.…”

“…Coyotes expanding into the southeastern United States likewise bear evidence of introgression from dogs ( Adams et al 2003 ). There is currently no evidence of coyote hybridization with dogs or wolves in the northwestern flank of their expansion, but coyotes moving into Central America are suspected to be hybridizing with dogs based on morphological characters ( Cove et al 2012 , Hody 2016 ).…”

“…Coyotes may represent a new top predator in eastern North America and other parts of the continent, with cascading effects on predator communities and disease dynamics ( Gompper 2002 , Levi et al 2012 ). Likewise, the recent arrival of coyotes in Panama may position them to colonize South America, with unknown implications for tropical ecosystems ( Hidalgo-Mihart et al 2004 , Méndez-Carvajal and Moreno 2014 , Hody 2016 ). Rigorously testing the causes and consequences of coyote range expansion requires an accurate historical context for where the species previously occurred.…”

Coyote (Canis latrans) in South America: potential routes of colonization

“…Within the corridor, the most important city is Panama, which presents the highest population density, 5044 inhabitants per km 2 , and has altitudes ranging from 0 to 3200 masl. Within the corridor is the province of Darién, region with the southernmost record of coyotes on the continent and the nearest to South America (Hody et al 2019).…”