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Alexander Center For Applied Population Biology
Camera-Shy Cats
Measuring Up
Measuring around eight feet from head to tail and weighing about 200 pounds,
the jaguar is the largest cat in the Americas.
But some grow much larger—the
largest jaguar ever recorded weighed a whopping 347 pounds! Large cats need
a large prey base—another factor researchers consider when building
population models.
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Clearing land for cattle pastures creates a lot of problems for jaguars. Not only is their habitat and food source, such as peccaries or tapir, gone, but it forces the big cats to hunt cattle and chickens, putting them in conflict with the settlers.
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National Monuments and Chance Encounters
The situation in zoos could not be more different. After decades of
successful care and management of jaguars, zoo scientists have an abundance
of data and tools at their disposal for studying the cryptic creatures. And
at Lincoln Park Zoo, home to the Alexander Center for Applied Population
Biology, population biologists have years of expertise studying and
conserving threatened populations like the jaguar. Which is why three
Alexander Center scientists are now guiding efforts to save jaguars in
Argentina, where the cat is known as a Monumento Natural Nacional, a
“National Natural Monument.”
Getting called a Natural Monument in Argentina is not quite the honor it
sounds like—Natural Monuments are equivalent to endangered species in the
U.S. And similar to U.S. practice, when a species is declared a Natural
Monument in Argentina, a team of experts is assembled to develop and
implement a recovery plan for it. The newly formed jaguar-recovery team’s
task was far from straightforward, however. Data on the mysterious jaguar
was sporadic, with different teams of researchers concentrating on different
habitats and problems using different methods and assumptions. Missing was a
big-picture perspective, a risk-assessment model to gauge just how
threatened the jaguar population was in Argentina and what its prospects
were for the future. Without that model, it would be difficult for the
recovery team to determine the best way to go forward.
A chance encounter in 2001, the year Argentina declared the jaguar a Natural
Monument, led the recovery team to the tools they needed to build the model.
While in England attending the Society for Conservation Biology annual
conference, Earnhardt, who heads the Alexander Center, met Argentine
biologist Mario di Bitetti, Ph.D. The two scientists began discussing
Argentina’s jaguar population and Earnhardt mentioned that the zoo had
expertise with Population Habitat Viability Analysis (PHVA), a tool that
could help the recovery team make the model they were looking for.
Participants at the jaguar conservation planning meeting in Brasilia, Brazil. Lincoln Park Zoo staff planned and led the meeting with scientists from Brazil and Argentina.
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An international team to conserve the jaguars was born. Through its
field-conservation grant program, the zoo began to fund the jaguar work of
di Bitetti in Argentina and of Laury Cullen, Ph.D., in neighboring Brazil.
Then Earnhardt was invited to Argentina to help create the jaguar-recovery
plan using population-biology methods. Within months, Earnhardt brought two
other Alexander Center scientists on board, Population Biologist and Ph.D.
candidate Lisa Faust, and Post-doctoral Research Associate Eric Lonsdorf,
Ph.D., to develop a specialized computer model of the Argentine jaguar
population. This summer, the zoo researchers convened and led the second
PHVA meeting. “It was challenging and quite entertaining to try to organize
a meeting that was going to take place in Brazil from our office in
Chicago,” says Earnhardt. “For one thing, none of us at the zoo speak
Portuguese!”
After months of planning and broken English, the meeting went off without a
hitch. Earnhardt, Faust and Lonsdorf traveled to Brasilia, Brazil to
demonstrate how PHVAs work and to explain how to collect the types of data
needed for the computer models. “The computer models are necessary,”
explains Earnhardt, “because computers can take into account many complex
factors and integrate these factors much more precisely than the human
brain.” In building the model, the zoo team will organize data such as birth
rates, prey availability and habitat types from many different researchers
into one layered system.
Next: Modeling in the Wild
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