CONSERVATION Corridors are important because species rely on the migration of a few animals from one region to another, to intermix gene pools and to repopulate areas devastated by natural disasters or disease. Costa Rica and other countries have begun protecting corridors for jaguars and other large mammals, reports Elisabeth Rosenthal

Hector Porras-Valverdo tried to adopt a Zen attitude when he discovered that jaguars had turned two of his cows into carcasses. Their numbers may have dwindled, but they still roam the forests in eastern Costa Rica, making their presence known by devouring the occasional chicken, pig or cow. “I understand cats do this because they need to survive,” said Porras-Valverdo, 41, a dairy farmer.

A few years ago, he acknowledged, his first reaction might have been to reach for a gun. But his farm now sits in the middle of land that Costa Rica has designated a “jaguar corridor” – a protected pathway that allows stealthy, nocturnal animals to traverse areas of human civilisation. In the past few years, such corridors have been created in Africa, Asia and the Americas to help animals cope with 21st-century threats, from encroaching highways and malls to climate change. These virtual pathways represent an important shift in conservation strategy.

Like many nations, Costa Rica has traditionally tried to protect mammal species like jaguars by creating sanctuaries – buying up land and giving threatened animals a home where they can safely eat, fight and breed to eternity. But in the past decade or so, scientists have realised that connecting corridors are needed because many species rely for survival on the migration of a few animals from one region to another, to intermix gene pools and to repopulate areas devastated by natural disasters or disease. Placing animals in isolated preserves, studies have found, decreases diversity and risks dulling down a species.

Alan Rabinowitz, a zoologist and president of Panthera, an organisation that studies and promotes conservation of large cats said migration routes were especially vulnerable in rapidly developing countries, where new roads, shopping malls, dams, playgrounds and subdivisions could spring up overnight, blocking the animals’ passage.

Virtual trails that are ‘protected’

To correct this oversight, Costa Rica and other countries have begun identifying and protecting corridors for jaguars and other large mammals, like tigers, snow leopards and pandas. Most of the corridors are not obviously demarcated pathways, but virtual trails, “protected” in the sense that builders and planners are not permitted to introduce obstacles to the animals’ movements through the area. The idea is not to stop building entirely, but to adjust development so that animals can move through landscapes that humans also occupy. The threat of global warming has added to the urgency of creating corridors because animals will need to shift habitats as temperatures rise from climate change. “This is an idea that people are finding very compelling, and especially compelling now because with changing climate, species will need the capacity to move,” said Norman Christensen, a professor of ecology at Duke University, whose team is working to define corridors in Central America, India and Africa. While Christensen called Costa Rica “the poster child” for its efforts, he said corridors for large mammals were also being created in Uganda and China.

Jaguar genetic make-up
Part of the reason that conservationists had in the past focused on preserves was that there was a lack of good data on the travel and breeding patterns of large animals like jaguars; these big predators favour dense jungles and are nocturnal and extraordinarily shy. When new techniques allowed scientists to take a first look at the jaguar genome a decade ago, they were shocked to discover that jaguars from the northern reaches of Mexico had exactly the same genetic makeup as those from the southern tip of South America.

That meant that over time, some jaguars were moving up and down the Americas to breed; otherwise, the isolation of jaguar populations in different regions would have caused their genetic makeups to diverge. At least some males from Colombia were travelling to Panama to mate, and others were moving from Mexico to Belize. “It was surprising, but it seemed to say they had one continuous habitat,” said Rabinowitz, the zoologist.

In Costa Rica, Panthera is conducting research to better define the routes taken by jaguars.

While local farmers are now willing to forgive a dead cow or two to allow jaguars to survive as a species, they are often reluctant to make larger sacrifices. Just outside Las Lomas, a proposed hydroelectric project would involve building a huge dam across a valley, creating a body of water a third of a mile wide and more than three miles long. The new project will mean jobs, an increase in property values and improved basic services for the area, including roads and piped water, said Fallas Ramirez, the agronomist. And the community, he said, cannot just forsake all that.“For us, and the jaguars, it’s just an obstacle,” said Salom, the biologist, who is looking into alternative solutions, like an animal bridge or a smaller dam. “So we’re thinking, ‘How can we mitigate this?”’
NYT News Service