Using Footprints to Do Headcounts of Tapirs in the Wild

May 22, 2018
Contact:

Tim Lucas, (919) 613-8084, tdlucas@duke.edu

jewell moreira tapir footprints headcount

Researchers collect tapirs’ footprints on dirt roads in Brazil. (Credit: Pró-Tapir)

Note: Zoe Jewell and Sky Alibhai are available for additional comment in English at (919) 345-3690 or info@wildtrack.org. Danielle Moreira is available for comment in Portuguese or English at daniomoreira@gmail.com.

DURHAM, N.C. — Footprints left by lowland tapirs in the wild can be used to identify the individual animal that made them and help scientists more accurately assess the size and reproductive viability of local populations, a new study by researchers from the United States and Brazil finds. 

Tapirs are large herbivores that play a vital ecological function in many tropical forests by dispersing the seeds of fruit they eat in their dung as they move about – helping renew and maintain the distribution and diversity of forest tree species. 

In recent decades, however, their numbers have shrunk by nearly 30 percent, and the IUCN Red Lists now classifies them as being vulnerable to extinction. 

“Estimating the size and health of tapir populations in the wild is extraordinarily challenging using traditional methods such as camera traps because tapirs have no special markings that distinguish one individual animal from another. Their paw prints, on the other hand, do differ. Each tapirs’ digits and foot pads have a unique shape,” said Zoe Jewell, adjunct associate professor at Duke University’s Nicholas School of the Environment and principal research associate at the JMP Division of SAS. 

“This makes footprints a very efficient and low-cost method of identification that can be used to monitor tapirs in the field without interfering with their natural behavior or ecology,” said Sky Alibhai, also an adjunct associate professor at Duke’s Nicholas School and principal research associate at the JMP Division of SAS. 

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Camera traps reveal tapirs’ nighttime movements. (Credit: Pró-Tapir)

In their new study, the Brazilian and American scientists used an interactive software tool called the Footprint Identification Technique (FIT) to analyze 440 digital images of tapir footprints collected in a nature preserve in the biodiverse Atlantic Forest of Brazil.

FIT uses a specially developed algorithm to “read” digital images of animal footprints collected in the field and identify the species, sex and age-class of the animal that made the tracks. It can even match tracks to individual animals.

“It was able to analyze the 440 footprint images we collected and identify that they were made by 29 different individuals – allowing us to determine the minimum number of tapirs that are using the reserve as a habitat,” said Danielle O. Moreira, postdoctoral fellow in conservation biology at Universidade Federal do Espírito Santo in Vitoria, Brazil. 

“Used in conjunction with other identification methods, this gives us a powerful tool to help conserve this species, which plays a critical role in maintaining the health not only of its own habitats but also those of other threatened species in the biodiverse Atlantic Forest region of Brazil,” she said.

Moreira organized the fieldwork for the study while she was a postdoctoral researcher at Duke’s Nicholas School in 2014-15. 

Moreira, Alibhai, Jewell and their colleagues published their peer-reviewed study March 29 in the open-access journal PeerJ.

To conduct the study, they surveyed for tapir footprints along 17 dirt roads in Reserva Particular do Património Natural Recanto das Antas, a privately owned reserve encompassing 5,456 acres of forests, grasslands and farmlands in the Brazilian state of Espírito Santo. The reserve is home to one of the Atlantic Forest’s few tapir populations still believed to be a viable breeding colony. 

The researchers conducted their surveys on the reserve’s dirt roads because tapirs are known to use them frequently, and because the roads cross and connect many of the reserve’s different habitats. Because tapirs are most active between dusk and dawn, the surveys were done early in the morning or late in the afternoon over a 10-month period between March 2014 and June 2015.

“Tapirs are considered a critically important landscape architect species in the Atlantic Forest,” Alibhai said. “Unfortunately, as farming and other human activities encroach deeper into the forest, their population has shrunk by 30 percent over the last three decades due to hunting and habitat loss, and the IUCN projects another 30 percent decline over the coming 30 years. This poses a very serious threat to a species like tapirs, which are slow reproducers.”

“Our next step is to estimate population size on a broader geographic scale and gather more information about these populations to better understand the conservation status of tapirs in this region,” Moreira said.

FIT software is an add-on to JMP software from SAS and can be customized for use on a wide range of different species and in different terrains.

Moreira, Alibhai and Jewell conducted the new FIT-enabled study with colleagues at the Universidade Federal do Espirito Santo; Projeto Pró-Tapir; the JMP Division of SAS; and Duke’s Nicholas School. 

Funding came from Fibria Celulose S.A., Idea Wild, and through a fellowship awarded to Moreira by Conselho Nacional de Desenvolvimento Científico e Tecnológico/Ciêncas sem Fronteiras. 

CITATION: "Determining the Numbers of a Landscape Architect Species (Tapirus terrestris) Using Footprints,” Danielle O. Moreira, Sky K. Alibhai, Zoe C. Jewell, Cristina J. daCunha, Jardel B. Seibert and Andressa Gatti; Peer J, March 29, 2018. DOI: 10.7717/peerj.4591

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