EDUARDO CESAR (photo taken at the Zoological Gardens Foundation of São Paulo)The cougar (Puma concolor), one of the biggest predators of the Americas, is still not extensively studied by Brazilian scientistsEDUARDO CESAR (photo taken at the Zoological Gardens Foundation of São Paulo)
Genetic analyses are unveiling some of the history and ecology of the puma (Puma concolor), one of the biggest felines native to Brazil. Only the jaguar (panthera onça) is bigger. These big, discrete cats are highly adaptable and can survive even in poorly forested regions. The pumas are being challenged by hunting and by highways, as the concurrent research work conducted by two researchers indicates. The two have never met personally: Camila Castilho, currently at the University of São Paulo (USP), and Renata Miotto, currently at the University of São Paulo’s Luiz de Queiroz School of Agriculture (Esalq), in the city of Piracicaba.
The two researchers studied the genetic aspects of local puma populations and achieved similar results, as reported in Renata’s article, published in Conservation Genetics in 2011, and in Camila’s article, published this year in Genetics and Molecular Biology. The first important aspect is that there is very little genetic difference among pumas in these regions, a sign of a non-fragmented population. This indicates that the animals are able to travel great distances and maintain the flow of genetic material, even though the forest are not continuous. Jaguars, however, differ from pumas in this respect, in that they rarely venture out of the jungle and remain isolated in fragments, generating distinct populations, as already described in other studies.
Actually, pumas form continuous populations throughout extensive areas. Camila, who worked on her research during her doctorate at the Federal University of Rio Grande do Sul (UFRGS), found that these areas encompass most of the State of Santa Catarina, part of the south of the State of Paraná and some extensions in the far north of the State of Rio Grande do Sul, a total of more than 140 thousand square kilometers. The region studied by Renata, at that time enrolled in a doctoral program at the Federal University of São Carlos (UFSCar), was more restricted, but extensive nonetheless: approximately 1,700 square kilometers in São Paulo State, which includes 15 municipal regions, among them Ribeirão Preto, Rio Claro and São Carlos.
Another similar finding of the two studies shows that at some point in the last century the number of pumas dropped drastically. Population genetics refer to this event as a population bottleneck. When such a bottleneck occurs, the population loses part of its genetic diversity, which can cause problems in some cases. “Genes are lost at random and therefore maybe there was no major loss,” Camila explains, “but it is likely that an unfortunate event could happen,” such as the loss of a specific gene that enables the animal to deal with changes in the environment. When a bottleneck is detected, there is no doubt that the reason is some imbalance in the population. This could be a significant reduction in the animal’s size or, more rarely, a drastic change in the proportion between males and females.
Sugarcane fields
At this point, the studies begin to differ. São Paulo state, where Renata does her work, is covered with sugarcane fields. “Most of the fields were planted in the 1960s and 1970s, because of the National Ethanol Program [Proálcool],” says the researcher. “Genetic data indicates that the bottleneck may have occurred at that time.” In this case, many pumas may have died during this period of massive deforestation, after which the population may have rebounded, as their prey adapted to living in the sugarcane plantations. “The felines in this region usually hunt armadillos, deer, capybaras and other rodents,” she says. These animals apparently adapt well to farmland; some of them even feed on sugar cane. Given the presence of abundant food, the pumas could easily live in these regions, without becoming a problem for the plantation owners.
Busy highways that crisscross the entire state are the main problem that these animals face today. It is practically impossible for these highways to be crossed by pedestrians, whether human or feline. This might block the routes travelled by pumas and reduce their genetic variability.
In addition to the highways that restrict puma travel, the animals are prone to being run over – a major cause of mortality. “The young males that move far away from where they were born are the main victims,” says Renata. Of the 23 sample animals that had been run over, 16 were males.
Anhanguera, a puma named after the highway where it had been run over in 2009, was a young male. “The mortality differential may alter the gender proportion, which could be detected as a bottleneck.” The reason is that the male pumas are the messengers of genetic material, as they move to a distant region where they finally settle down and mate.
The females remain close to where they were born, confirms Renata, who spent five years at the Ecological Station of Jataí monitoring the big cats. The station lies in the municipal region of Luis Antônio, near the city of Ribeirão Preto. During this time, Renata explored trails and collected fresh droppings from which she extracted genetic material. The data, published this year in Biotropica, show that all the resident pumas are females.
Bovids
In the South, Camila came across a relationship of conflict between human beings and the leão-baio, as this feline is referred to in the State of Santa Catarina. Various types of bovids – cattle, goats, sheep – are raised extensively in this state, and the animals are not confined. In addition to pacas, common agoutis, and deer, the pumas also feed on domestic animals. As a result, they are hunted by armed farmers. “Although hunting is illegal, we know that there is extensive hunting in this region,” says Camila. Camila gradually managed to wear down the farmers’ resistance. They finally gave in and supplied her with the pumas they had hunted down so that she could extract genetic material. The researcher restricted her research work to the southern part of the State of Santa Catarina, where farms spread over high terrain with clumps of vegetation in the middle of the pasture lands. The pumas take refuge in these clumps of vegetation and in the vegetation along river banks. From time to time, the pumas come across goats or calves looking for shelter.
As in São Paulo State, the data collected by Camila shows that the population bottleneck happened in the last century, coinciding with the massive deforestation of the Paraná pine tree (araucaria angustifolia) forests native to that region. At present, it seems that hunting – and not a lack of habitat – is responsible for the high mortality rate of pumas in that area. “Forest connectivity does not seem to be a problem,” says Camila. By means of ecological models that analyze the landscape, she suggests, in an article published in 2011 in Mammalian Biology, that there is no barrier preventing these animals from travelling all over the region that she covers in her study. This area encompasses most of Brazil’s South Region. The insignificant family ties among the individual animals she analyzed corroborate this idea. “Only 6.6% of the individual felines we analyzed had any kinship,” she says. In her opinion, it is necessary to raise the awareness of farmers about the ecological importance of the big predators and seek solutions, such as building corrals where the cattle can be sheltered at night.
Even though they had never met personally, the two researchers pursued parallel paths. They are both currently enrolled in post-doctoral programs and have put genetics on hold to concentrate on landscape analysis. “These are complementary approaches,” explains Camila. In view of the information provided by the distribution of genetic variation, new issues have come up, leading them to try to understand the environment where pumas circulate. In doing so, the researchers intend to detect the problems that the pumas face and propose solutions to maintain feasible populations of this huge feline, native to most of the Americas, with the exception of most of Argentina and the Eastern region of North America.
The two researchers are currently working in São Paulo. Renata is working on a data base on native plants and on the occupation of the region where she conducted her research, including a detailed map of the highway network and the flow of vehicles. This data, together with the genetic data, will form a dispersion model. Concurrently, she is compiling data on the animals that were run over. She has been able to increase her collection of genetic samples with the help of the Forest Rangers. “Based on these models, I plan to evaluate the pumas’ preferred routes to define what can be done in terms of landscape stewardship,” she explains. Camila is concentrating her research project on the mosaic of the Bocaina and Mantiqueira Mountain Ranges, in the northeastern region of São Paulo State, including the region of São José dos Campos. She will evaluate the available habitat in this region and the possibility of the pumas moving around. “I will establish permeability values to detect the priority areas in terms of conservation.”
Together, the two research projects may help to reduce the imbalance between North and South America regarding the knowledge of this imposing predator. The two researchers may also submit proposals for animal husbandry practices that could improve relations between farmers and predators, and for walkways above or tunnels under the highways, so that the pumas can cross them.
Scientific articles
CASTILHO, C. S. et al. Genetic structure and conservation of Pumas in the South-Brazilian Atlantic Rain Forest. Genetics and Molecular Biology. v. 35 (1), p. 65-73. 2012.
CASTILHO, C. S. et al. Landscape genetics of pumas (Puma concolor) in southern Brazil. Mammalian Biology. v. 76 (4), p. 476-83. 2011.
MIOTTO, R. A. et al. Monitoring a puma (Puma concolor) population in a fragmented landscape in Southeast Brazil. Biotropica. v. 44 (1), p. 98-104. 2012.
MIOTTO, R. A. et al. Genetic diversity and population structure of pumas (Puma concolor) in southeastern Brazil: implications for conservation in a human-dominated landscape. Conservation Genetics. v. 12 (6), p. 1.447-55. 2011.
