Featured Research

from universities, journals, and other organizations

Who are we sharing the planet with? Millions less species than previously thought, new calculations suggest

Date:
June 2, 2010
Source:
University of Melbourne
Summary:
New calculations reveal that the number of species on Earth is likely to be in the order of several million rather than tens of millions. The findings, from an Australian-led study, are based on a new method of estimating tropical insect species -- the largest and one of the most difficult groups on the planet to study -- having significant implications for conservation efforts.

Insect collection. New calculations suggest that the number of species on Earth is likely to be in the order of several million rather than tens of millions.
Credit: iStockphoto/Christian Skorik

New calculations reveal that the number of species on Earth is likely to be in the order of several million rather than tens of millions. The findings, from a University of Melbourne-led study, are based on a new method of estimating tropical insect species -- the largest and one of the most difficult groups on the planet to study -- having significant implications for conservation efforts.

The study's lead author, Dr Andrew Hamilton from The University of Melbourne's School of Land and Environment, said he was driven to more accurately calculate species numbers because humans were more certain of the number of stars in our galaxy, than fellow species on their own planet.

"Our understanding of species numbers has been clouded by one group of organisms, tropical arthropods, which include insects, spiders, mites and similar organisms. Estimates for this group have ranged from a few million up to 100 million," says Dr Hamilton.

Dr Hamilton and a team of international researchers have applied probability modelling techniques (models often used in financial risk estimates) to data from numerous previous studies. They found that there is a 90% chance that there is somewhere between 2 and 7 million tropical arthropod species, with a best estimate of 3.7 million.

With the addition of approximately 50,000 vertebrates (birds, mammals, amphibians and reptiles), 400,000 plants and possibly 1.3 million other organisms (mostly microorganisms, but excluding the bacteria for which we know very little about), this leaves us with a best estimate of around 5.5 million species with whom we share planet Earth. Furthermore, the study found that there is less than a 0.001% chance that the often-quoted value of at least 30 million total species is true.

"Our study is significant in this the International Year of Biodiversity, giving us a more realistic starting point for estimating extinction rates -- a profound hurdle in conservation biology. Extinction rates are typically estimated through knowing the area of habitat that has been lost, but to know how many species have been lost, we need to know how many were present in the first place. Obviously, if we are starting with less species, we may be worse off than we thought, and also be reducing the complexity of ecosystems even faster," says Dr Hamilton.

"The findings also mean that in spite of 250 years of taxonomic research, around 70% of arthropods await description."

"Many scientists have redone the calculations using different values and arrived at wildly different answers. Our work reran the same calculations, which use various inputs, such as the number of beetle species in the canopy of a typical rainforest tree, but accounted for uncertainty relating to these inputs and, therefore, uncertainty in the final estimation how many species there are."

The study will be published in the current edition of the international journal The American Naturalist.


Story Source:

The above story is based on materials provided by University of Melbourne. Note: Materials may be edited for content and length.


Journal Reference:

  1. Andrew J. Hamilton, Yves Basset, Kurt K. Benke, Peter S. Grimbacher, Scott E. Miller, Vojtech Novotný, G. Allan Samuelson, Nigel E. Stork, George D. Weiblen, Jian D. L. Yen. Quantifying Uncertainty in Estimation of Tropical Arthropod Species Richness. The American Naturalist, 2010: 100510130432020 DOI: 10.1086/652998

Cite This Page:

University of Melbourne. "Who are we sharing the planet with? Millions less species than previously thought, new calculations suggest." ScienceDaily. ScienceDaily, 2 June 2010. <www.sciencedaily.com/releases/2010/06/100602142045.htm>.
University of Melbourne. (2010, June 2). Who are we sharing the planet with? Millions less species than previously thought, new calculations suggest. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2010/06/100602142045.htm
University of Melbourne. "Who are we sharing the planet with? Millions less species than previously thought, new calculations suggest." ScienceDaily. www.sciencedaily.com/releases/2010/06/100602142045.htm (accessed October 22, 2014).

Share This



More Plants & Animals News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Cadaver Dogs Aid Search for More Victims of Suspected Indiana Serial Killer

Cadaver Dogs Aid Search for More Victims of Suspected Indiana Serial Killer

Reuters - US Online Video (Oct. 21, 2014) — Police in Gary, Indiana are using cadaver dogs to search for more victims after a suspected serial killer confessed to killing at least seven women. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
White Lion Cubs Unveiled to the Public

White Lion Cubs Unveiled to the Public

Reuters - Light News Video Online (Oct. 21, 2014) — Visitors to Belgrade zoo meet a pair of three-week-old lion cubs for the first time. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
'Cadaver Dog' Sniffs out Human Remains

'Cadaver Dog' Sniffs out Human Remains

AP (Oct. 21, 2014) — Where's a body buried? Buster's nose can often tell you. He's a cadaver dog, specially trained to find human remains and increasingly being used by law enforcement and accepted in courts. These dogs are helping solve even decades-old mysteries. (Oct. 21) Video provided by AP
Powered by NewsLook.com
White Lion Cubs Born in Belgrade Zoo

White Lion Cubs Born in Belgrade Zoo

AFP (Oct. 20, 2014) — Two white lion cubs, an extremely rare subspecies of the African lion, were recently born at Belgrade Zoo. They are being bottle fed by zoo keepers after they were rejected by their mother after birth. Duration: 00:42 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins