BBC NEWS Americas Africa Europe Middle East South Asia Asia Pacific
BBCi NEWS   SPORT   WEATHER   WORLD SERVICE   A-Z INDEX     

BBC News World Edition
 You are in: Science/Nature  
News Front Page
Africa
Americas
Asia-Pacific
Europe
Middle East
South Asia
UK
Business
Entertainment
Science/Nature
Technology
Health
-------------
Talking Point
-------------
Country Profiles
In Depth
-------------
Programmes
-------------
BBC Sport
BBC Weather
SERVICES
-------------
EDITIONS
Tuesday, 2 July, 2002, 12:08 GMT 13:08 UK
Plant population estimated
Orchid, BBC
An angiosperm head-turner: An orchid
There may be far more flowering plants on Earth than was thought.

A new calculation, by leading botanist Dr David Bramwell, suggests there could be about 422,000 species of angiosperm.


We need to make the politicians aware of the size of the problem; to see how much of the world's biodiversity can be saved

Dr David Bramwell
Conservationists say the estimate underlines the urgent need to complete a global inventory of plant diversity. Much of the planet's botanical wealth is concentrated in parts of the world where species-rich tropical and Mediterranean habitats are under greatest pressure.

"By increasing the total number of species, we also increase the number that are threatened," Dr Bramwell, the director of the Jardin Canario "Viera y Clavijo" on Gran Canaria, Spain, told BBC News Online.

He believes more than a fifth of species may now be endangered.

The new estimate is for plants known to science, and does not include speculative numbers of species yet to be discovered.

Wide range

Angiosperms are flowering plants that produce seeds enclosed in fruit. The flowers allow animals, particularly insects, to transport pollen between the plants.

Although they are thought to have evolved relatively recently - about 125 million years ago - they are the dominant plants on the planet.

The angiosperms
The dominant plant division
Includes most of the plants we eat
Their flowers aid sexual reproduction
Seeds are enclosed in a fruit
Characteristics have co-evolved with animals, particularly insect species
Dr Bramwell made his estimate (421,968) by adding together the number of plants in each region of the world, concentrating on plants only known from one country or island, and allowing for overlap of floras from one country to another.

"What I have done is take a baseline flora - the largest flora in each region - and then count the number of endemics from the other countries that are definitely not in that baseline. The main point is that my system eliminates a lot of the duplication that occurred in previous estimates."

The figure arrived at is substantially higher than previous estimates that ranged from 231,000 to 320,000 species. However, it fits well with another recent estimate by Dr Raphael Govaerts, from the Royal Botanic Gardens, Kew, UK.

Dr Govaerts used a different method of counting and produced a figure of 422,127.

More resources

The latest estimate has been published in Plant Talk, an international periodical on the conservation of the world's plants.

Those working in the field say the number greatly boosts the argument that more resources should be allocated to the classification and conservation of plant diversity.

Under the international Convention on Biological Diversity, a Global Strategy for Plant Conservation is being worked on. One of its targets is to list all the plants of the world.

"At least now we have an idea of the size of the problem," Dr Bramwell said. "But we need also to get an idea of the conservation status of each plant.

"Conservation isn't only biology, it's politics as well - obviously. We need to make the politicians aware of the size of the problem; to see how much of the world's biodiversity can be saved."

See also:

19 Apr 02 | Science/Nature
13 Dec 00 | Science/Nature
04 Apr 02 | Science/Nature
02 Jul 02 | Science/Nature
25 Apr 02 | Science/Nature
Internet links:


The BBC is not responsible for the content of external internet sites

Links to more Science/Nature stories are at the foot of the page.


E-mail this story to a friend

Links to more Science/Nature stories

© BBC ^^ Back to top

News Front Page | Africa | Americas | Asia-Pacific | Europe | Middle East |
South Asia | UK | Business | Entertainment | Science/Nature |
Technology | Health | Talking Point | Country Profiles | In Depth |
Programmes