May 17, 2021

Cities can save the tiger | Science

Cities can save the tiger | Science


Tiger, Panthera tigris, seemed doomed to extinction. He had disappeared from Bali in the 50s of the last century, from the island of Java in the 70s and from Central Asia in the late 1980s. Where he still survives, both their number and geographical range were reduced to a minimum: in 2010 the tigers occupied 0.5% of the territory they had in the past and its population was about 3,200 copies, compared to 100,000 at the beginning of the 20th century. Everything indicated that in a few decades they would only survive in the zoos. However, since 2016 there has been a slow recovery that could accelerate throughout the century thanks, for once, to humans.

Human's own dynamics are giving the tiger a chance. This is what a recent study by researchers from the Society for the Conservation of Wildlife (WCS, for its acronym in English) and two universities in the US. The work points out that, in addition to the great conservation efforts under way to save the great Asian cat, recent and incipient changes in the demographics of Asians may be helping.

The tigers live today in 0.5% of the territory they came to have but their population is beginning to recover

Almost a century behind Europe and North America, Asia would be experiencing its own demographic transition. There are two most outstanding elements of this process that is still in its infancy. On the one hand, the population shows signs of stabilizing and, on the other, one of the greatest migrations from the history of the countryside to the cities is under way. In the last 30 years, for example, the urban population in China has gone from 23% to 55%. All this is releasing large amounts of land for the return of the tigers and reducing the pressure on them.

"Cities help with rural migration," WCS ecologist and lead author of the study, Eric Sanderson, said in an e-mail. "But, even more important is the fact that the people of the city have fewer children than the people of the towns, which is causing a stabilization of the population," he adds. In 1758, when the Swedish naturalist Carl Linnæus cataloged the tiger, there were about five hundred million inhabitants on the continent, today it is 4,400 million. The latest projections show that Population growth in Asia is slowing and that, from the middle of the century or earlier, demographic regression can occur, particularly in rural areas.

Sanderson's study, published in the magazine Biological Conservation, number 51.1 million people living in or near the land of the tiger. Of the five scenarios that this research model, in all there is an initial increase in population, but in four, in the second part of the century humans in these areas could go down by 20 million. But as indicated by the American ecologist, more important than the total numbers is the intense urbanization. In the 42 areas where there are still tigers, only 11% of the population was urban in 2000. A century later, they could have gone up to 69%.

The Indian city of Vijayawada, near one of the territories of the tiger, has won the majority of its 800,000 inhabitants in recent decades.
The Indian city of Vijayawada, near one of the territories of the tiger, has won the majority of its 800,000 inhabitants in recent decades.

"The urban lifestyle makes it easier to choose the size of the family, and in cities, there are usually better educational and employment opportunities and, therefore, more income to invest in the well-being of children. women are more likely to receive an education in the city than in the villages, which also means that they can have more options about the family … It must also be remembered that cities are centers of economic and political power, so working with people to care for tigers (and other wildlife) can generate the necessary government support for conservation efforts, "says Sanderson.

But it's not worth any kind of city. Versus the crazy urbanization During a good part of the 20th century, an integral and relatively ordered urban development is necessary. "We must take into account all these factors and others related to governance and public policies but, in general, we believe that they are the best option we have to keep the tiger in the long term," concludes Sanderson. And along with tigers, many other species and entire ecosystems can benefit from the march of humans.

In many ways it is something that is already happening in other regions of the world, where the modern demographic transition and urbanization have long since matured. In Europe, for example, various studies have shown how the animals are recovering part of the space that humans snatched in the past.

"In Europe, we are going through both carnivores and herbivores," says Aurora Torres, of the German Center for Integrated Biodiversity Research (iDiv). "The abandonment of agricultural areas is leaving more habitat available, and direct persecution has been reduced after the change of attitude towards animals," he adds. The Spanish researcher works in the field of ecological restoration, which goes beyond the mere reintroduction of a species into an area and seeks "the restoration of the entire ecosystem," he says. The iDiv participates in the pan-European project Rewilding Europe (something like reasilvestrando Europa), an initiative to recover wildlife in the continent and that already has a network of 60 local initiatives for this rewilding.

A recent study on ecological restoration It showed that, in addition to being possible and being a value in itself, it would help to mitigate the impact of climate change on different ecosystems and on humans themselves. For example, replacing ruminant livestock animals with non-ruminant wild animals would reduce methane emissions. One of its authors, the biologist of Institute of Ecology of the Netherlands Liesbeth Bakker said in a note: "With time, we can achieve a gradual increase in the state of nature of ecosystems."

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