Flora not flourishing in world's hotspots

Dec 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: Eradication efforts unite to preserve fairy-wren population

add to favorites email to friend print save as pdf

Related Stories

Group: Wildlife populations down drastically

15 hours ago

Populations of about 3,000 species of wildlife around the world have plummeted far worse than previously thought, according to a new study by one of the world's biggest environmental groups.

The Rise and Fall of Sugar in Hawai'i

Sep 25, 2014

There's one sugar plantation left in Hawai'i, just a few square miles left of an industry that once dominated the island chain. Sugar's profits and high-paying jobs are long gone, as are the native forests ...

How genes trace life on Earth

Sep 25, 2014

A complete tree of life – showing how and when organisms are related to each other – has long been desired by biologists, but obscured by the vagaries of the fossil record. ...

Avian expert warns migratory birds are facing annihilation

Sep 25, 2014

(Phys.org) —Millions of migratory birds that fly tens of thousands of kilometres between their homes in Australia and Siberia are facing annihilation as development destroys the vital feeding grounds they rely on during ...

Recommended for you

World's first microbe 'zoo' opens in Amsterdam

5 hours ago

The world's first "interactive microbe zoo" opened in Amsterdam on Tuesday, shining new light on the tiny creatures that make up two-thirds of all living matter and are vital for our planet's future.

User comments : 0