Where Jaguars Cross Other Will Follow
Written By Dr. Alberto González Gallina
Red de Ambiente y Sustentabilidad, Instituto de Ecología A.C. (INECOL)
2nd December, 2020
Jaguars together with other neotropical species only used purpose-built wildlife underpasses under a highway in Mexico, even when ‘large enough’ drainage structures were available. Drainage structures may work as crossings for some species but can’t substitute proper wildlife underpasses.
Figure 1. Male jaguar going through one of the wildlife underpasses under the Nuevo-Xcan-Playa del Carmen highway in Quintana Roo, México.
The king of the jungle threatened by roads and traffic
Jaguars are the Kings of the Mayan jungles and they have held that position for centuries. However, Jaguars are under siege and their reign is threatened by an ever-expanding human population who are logging, clearing habitat and building infrastructure at accelerated rates. Roads and traffic are especially detrimental because they not only allow developers and hunters to go deeper inside natural areas and impact wildlife, but highways also have their toll as many Jaguars are killed each year while attempting to cross.
But not everything is going against Jaguars! In 2011, the Federal Government of Mexico proposed the construction of a new 54 km highway connecting the center of the Yucatan Peninsula with the Mayan Riviera, but this time, for the first time, there would be mitigation efforts to avoid Jaguar mortality due to wildlife-vehicle collision. Through a collaborative partnership among academics, environmental consultants and road builders a total of 28 dedicated wildlife underpasses were designed and built for jaguars and five other priority species (ocelot, margay, tayra, tamanduas and spider monkeys) along the 54km highway. Crossing structures ranged from concrete pipes (1.5 m diameter) and box culverts (2 m wide x 1 m high) that also allowed drainage to dedicated wildlife underpasses which were box culverts 3.5 m wide x 4 m high with drift fencing, natural soil, no barbed wire close to the ground and vegetation management in the right of way to keep entrances clear while allowing tree growth.
Figure 2. Study area, location of the Nuevo Xcan-Playa del Carmen highway in thick gray line (left). Highway view, two lanes with shoulders (12 m crown) with 60 m right of way, and how the surrounding environment looks like (right).
Did they work, you might wonder? The answer is: yes. Using photo-trapping, we recorded a total of 24 jaguar crossings after one year of monitoring exclusively using wildlife underpasses, including at least four different males and two different females. In addition, more than 16 other native mammal species, including five of the targeted priority species, also used the wildlife underpasses. Thirteen species used wildlife underpasses compared with ten going through concrete pipes and nine in concrete culverts. While drainage structures under the highway do allow some animals to cross safely under the road, they are clearly not as effective as larger wildlife underpasses. Important features of the effective wildlife underpasses include fencing to funnel animals to the underpasses, natural soil substrate and a more permanent adjacent natural vegetation which in turn allow bigger animals such as jaguars to pass through.
Figure 3. (Left): View of the Nuevo-Xcan-Playa del Carmen highway in Quintana Roo, México, showing wildlife underpasses and arboreal crossings as rope bridges. On the right are photos of each type of underpass, including dedicated wildlife underpasses as well as box culverts and concrete pipes for drainage and wildlife.
Underpasses alone do not fully solve all the problems related to highway mortality of wildlife or the national decline in Jaguar populations, but it’s a promising start point for them and the rest of the neotropical mammal community. Our results clearly justify that all new roads in wildlife habitat in the neotropics must include dedicated wildlife underpasses specifically designed for the target species. However, wildlife crossing structures do not mitigate all the negative impacts of roads and traffic, and where possible, new roads should not be built in areas that support important wildlife populations. In addition, other complimentary measures should accompany these efforts along roads to increase the viability of Jaguar populations in Mexico and elsewhere!
Author information:
Dr. Alberto González Gallina Red de Ambiente y Sustentabilidad, Instituto de Ecología A.C. (INECOL) Carretera Antigua a Coatepec No. 351, El Haya, Xalapa, Veracruz, México. PC. 91073
Tel. 52(228)8421800 fodopo@hotmail.com
Source:
González-Gallina A, Hidalgo-Mihart MG, Castelazo-Calva V (2018) Conservation implications for jaguars and other neotropical mammals using highway underpasses. PLoS ONE 13(11): e0206614. https://doi.org/10.1371/journal.pone.0206614
*Second year monitoring (only wildlife underpasses):
González-Gallina A (2018). Jaguar and Other Mammal Use of Wildlife Crossing Structures on a Highway on North-Eastern Quintana Roo State (Mexico) Final Report for the Rufford Foundation. https://www.rufford.org/projects/alberto_gonz%C3%A1lezgallina
Editor:
Rodney van der Ree
Cite this summary:
González-Gallina, A. 2020. Where Jaguars Cross Other Will Follow. Edited by van der Ree, R. TransportEcology.info, Accessed at: https://transportecology.info/research/where-jaguars-cross [Date accessed].