Flora not flourishing in world's hotspots

December 10, 2008

Researchers at the University of Calgary have found the biodiversity picture in the region known as the "lungs of the Earth" contradicts commonly held views relating to extinction in that area.

A paper published in PLoS ONE by Jana Vamosi and Steven Vamosi outlines that the risk of extinction for plants is higher in countries close to the equator than previously thought.

"The tropics contain many ancient species of plants, leading many to consider tropical species as less susceptible to extinction -- but our study indicates that quite the opposite is, in fact, the case," says Steven Vamosi, an assistant professor in the Department of Biological Sciences at the U of C.

"The extinction risk for plants is high in countries close to the equator and even higher on islands, even after we take into account factors related to human activities and their use of the natural resources."

Previous studies on biodiversity in the tropics have focused on beetles, birds, mammals and molluscs. The Vamosi study mined worldwide databases for the number of plant species at risk in each country of the world, from Falkland Islands in the south to Greenland in the north, and looked at human factors such as GDP, population density and deforestation. Vamosi concentrated on data from vascular plants (ferns, conifers, and flowering plants), which includes such threatened species as the Canada Hemlock, Western Prairie Fringed Orchid, and Desert Lily, among many others.

Vamosi says he was surprised that human activity was not the primary cause of the increasing risk of extinction in the equatorial regions.

"Our findings differ from previous ones in that factors tightly linked to human activity were not particularly important in determining how many plant species were threatened with extinction. Instead, the most important factor seemed to be simply latitude. So, extinction dynamics may be very different between plant and animal species. Plant species near the equator may persist at naturally low population sizes or have small ranges, making them intrinsically more susceptible to a given amount of disturbance."

He adds that he would like to see the findings spur other researchers to bring more data to bear on this issue, given that most attention to date has focused on vertebrates.

Does this study put human disturbance off the hook? Vamosi says: No.

"This is not to say that human activities are not underlying contemporary risk of extinction; instead, it implies that plant species in a tropical country will, on average, be more sensitive to a given amount of human disturbance than those in a temperate country," he says.

Vamosi says that it is estimated that 20 to 45 per cent of species in the tropics are at risk. As a point of reference, in Canada, roughly 2 to 3 per cent are vulnerable to extinction.

Tropical ecosystems are considered the lungs of our planet as 60 per cent of the Earth's plant species are found in tropical rain forests, despite this area containing only 12 per cent of the Earth's land mass. The tropics are an important source of pharmaceuticals as well as food. The area is also habitat for a disproportionate percentage of the Earth's fauna, including butterflies, primates, birds, bats, and losses of tropical plants will often have disastrous consequences for such species. Because of the interconnectedness of the Earth's ecosystems, species loss near the equator can have significant effects on countries thousands of kilometers away.

Article: dx.plos.org/10.1371/journal.pone.0003886

Source: University of Calgary

Explore further: Humans may have occupied Southern Cone 14,000 years ago

Related Stories

Humans may have occupied Southern Cone 14,000 years ago

September 29, 2016

Humans may have occupied the Southern Cone 14,000 years ago, according to a study published September 28, 2016 in the open-access journal PLOS ONE by Gustavo Politis from CONICET and the Universidad Nacional del Centro de ...

Fossils can help predict future species survival

September 27, 2016

Many people are concerned about conservation of the planet's cute and cuddlies. But in a world of global climate change, sometimes we must prioritize which species we can and should save from extinction. Dr. Alycia Stigall ...

Wildlife meeting weighs how to save endangered species

September 24, 2016

Thousands of conservationists and government officials open talks in Johannesburg on Saturday to thrash out regulating international trade in elephant ivory, rhino horn and hundreds of endangered wild animals and plants.

Recommended for you

Giant dinosaur footprint discovered in Mongolia desert

September 30, 2016

One of the biggest dinosaur footprints ever recorded has been unearthed in the Gobi Desert, researchers said Friday, offering a fresh clue about the giant creatures that roamed the earth millions of years ago.

Fermi finds record-breaking binary in galaxy next door

September 29, 2016

Using data from NASA's Fermi Gamma-ray Space Telescope and other facilities, an international team of scientists has found the first gamma-ray binary in another galaxy and the most luminous one ever seen. The dual-star system, ...

Scientists: World likely won't avoid dangerous warming mark

September 29, 2016

A team of top scientists is telling world leaders to stop congratulating themselves on the Paris agreement to fight climate change because if more isn't done, global temperatures will likely hit dangerous warming levels in ...

Game theory research reveals fragility of common resources

September 29, 2016

New research in game theory shows that people are naturally predisposed to over-use "common-pool resources" such as transportation systems and fisheries even if it risks failure of the system, to the detriment of society ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.