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: Wolf-like animal seen roaming in northern Arizona

add to favorites email to friend print save as pdf

Related Stories

Evolution of competitiveness

Oct 29, 2014

Virtually all organisms in the living world compete with members of their own species. However, individuals differ strongly in how much they invest into their competitive ability. Some individuals are highly competitive and ...

Scientists work to save endangered desert mammal

Oct 24, 2014

Amargosa voles, small rodents that inhabit rare marshes of the Mojave Desert, have faced dire circumstances in recent years. Loss of habitat, extreme drought and climate change brought this subspecies of ...

Recommended for you

Breaking down DNA by genome

3 hours ago

New DNA sequencing technologies have greatly advanced genomic and metagenomic studies in plant biology. Scientists can readily obtain extensive genetic information for any plant species of interest, at a relatively low cost, ...

Is fleet diversity key to sustainable fisheries?

9 hours ago

Concern about fisheries is widespread around the world. Over the past several decades, a robust discussion has taken place concerning how to manage fisheries better to benefit ecosystems and humans. Much of the discussion ...

Strange, fanged deer persists in Afghanistan

10 hours ago

More than 60 years after its last confirmed sighting, a strange deer with vampire-like fangs still persists in the rugged forested slopes of northeast Afghanistan according to a research team led by the Wildlife ...

User comments : 0

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.