- Scientists have discovered new populations of Pampas deer in the savanna region along the southern edge of the Brazilian Amazon, hundreds of miles away from the species’ historical range.
- The findings illustrate the need for more detailed studies to assess the deer’s conservation status and that of other unrecorded species.
- While finding new populations is good news, it’s tempered by the fact that the largest of those groups is in an area known as Brazil’s Arc of Deforestation, where the land is fast being taken over for agriculture.
Scientists have uncovered hidden populations of Pampas deer (Ozotoceros bezoarticus) in savanna enclaves on the southern edge of the Brazilian Amazon, hundreds of miles from any historically known population of the species.
The discovery is detailed in a paper published recently in the journal Oryx and comes as good news for a species fast losing its habitat to farmland and cattle ranches. But it’s tempered by the fact that the largest of the newfound populations may already be in trouble due to fires in Brazil’s Arc of Deforestation, an area of rapid agricultural expansion.
“The fact that we didn’t know until recently about the occurrence of the pampas deer, a large mammal, in some of these savannah enclaves suggests that we may not know what we’re losing,” said study co-author Rahel Sollmann, an assistant professor at the Department of Wildlife, Fish and Conservation Biology at the University of California, Davis.
Locals on the southern border of the Amazon told the researchers that the Pampas deer population had declined in recent years following an influx of migrants into the region during the 1970s. That put extensive pressure on the species from habitat loss and fragmentation, hunting, and emerging diseases. Farmers have already transformed large areas of the region for the cultivation of soybeans and rice, as well as cattle ranching and other agricultural purposes.
As such, finding the deer proved difficult.
“The most challenging aspect of fieldwork was accessing some of those savannah enclaves,” said lead author Daniel Rocha, a Ph.D. student in ecology at UC Davis. “For instance, we planned an eight-day intensive camera trapping campaign in a savannah enclave within Mapinguari National Park. It took us five days and most of our resources just to reach [it]. By then, we concluded that it was impossible to conduct a systematic survey.”
Still, he says, the discovery has encouraged him to continue his research and “create awareness of the importance of these areas.”
The researchers covered 70,000 square kilometers (27,000 square miles) — an area the size of Ireland — over 16 months in the Brazilian states of Amazonas and Rondônia. Their 84 camera traps yielded 23 photo records of Pampas deer. However, they were unable to estimate population size, density or other important demographic parameters.
A major fire hit the larger of the populations studied, in Campos Amazônicos National Park and adjacent indigenous territories, last year. According to the Amazonian Fields Integral Protection Conservation Unit, the fires were all due to natural causes. In addition to fires, exacerbated by climate change, the Pampas deer face extensive threats due to their unique preference for grasslands at low elevations.
In their paper, the authors call for further assessment of these populations, as well as for greater protection and management. This echoes concerns raised in a 2008 study about the impact that the loss of a healthy deer population would have on the grassland. A healthy grassland is a biodiverse habitat, home to birds that migrate from North America, and other threatened species. If the Pampas deer habitat is lost, these other species could disappear too.
Susana Gonzalez, co-chair of the IUCN Deer Specialist Group, who was not involved in the recent study, describes its findings as “extremely important.” She says it gives hope for the recovery of the Pampas deer.
In a 1998 study, Gonzalez examined DNA sequences of 54 individual Pampas deer distributed throughout their present geographical range. The results demonstrated that the species once inhabited a much larger range.
“If the goal of conservation is to maintain long term population stability and preserve genetic variation, conservation efforts should focus on the restoration of deer habitats,” she says.
She adds conservation biologists should involve local communities and wildlife managers “to protect and conserve this emblematic deer that is so vulnerable.”
Banner image: A Pampas deer in Campos Amazônica National Park. Image by Ana Rafaela D’Amico.
Rocha, D., Vogliotti, A., Gräbin, D., Assunção, W., Cambraia, B., D’Amico, A., . . . Sollmann, R. (2019). New populations of pampas deer Ozotoceros bezoarticus discovered in threatened Amazonian savannah enclaves. Oryx, 53(4), 748-751. doi:10.1017/S0030605318001539
Vila, A. R., Beade, M. S. and Barrios Lamunière, D. (2008), Home range and habitat selection of pampas deer. Journal of Zoology, 276(1), 95-102. doi:10.1111/j.1469-7998.2008.00468.x
Gonzalez, S., Maldonado, J. E., Leonard, J. A., Vilà, C., Barbanti Duarte, J. M., Merino, M., . . . Wayne, R. K. (1998). Conservation genetics of endangered Pampas deer (Ozotoceros bezoarticus). Molecular ecology, 7(1), 47-56. doi:10.1046/j.1365-294x.1998.00303.x