Featured Research

from universities, journals, and other organizations

Environmental factors limit species diversity, lizard study finds

Date:
December 29, 2010
Source:
University of Rochester
Summary:
New research on lizards in the Caribbean demonstrates that species diversification is limited by the environment. The finding supports and extends the MacArthur-Wilson theory of island biogeography.

Anole lizard. According to researchers, in general, the larger the area, the greater the number of species that can be supported. For example, there are 60 species of anolis lizards on Cuba, but far fewer species on the much smaller islands of Jamaica and Puerto Rico. There are only 6 species on Jamaica and 10 on Puerto Rico.
Credit: iStockphoto/Frank Leung

New research on lizards in the Caribbean demonstrates that species diversification is limited by the environment. The finding supports and extends the MacArthur-Wilson theory of island biogeography.

It's long been accepted by biologists that environmental factors cause the diversity -- or number -- of species to increase before eventually leveling off. Some recent work, however, has suggested that species diversity continues instead of entering into a state of equilibrium. But new research on lizards in the Caribbean not only supports the original theory that finite space, limited food supplies, and competition for resources all work together to achieve equilibrium; it builds on the theory by extending it over a much longer timespan.

The research was done by Daniel Rabosky of the University of California, Berkeley and Richard Glor of the University of Rochester who studied patterns of species accumulation of lizards over millions of years on the four Caribbean islands of Puerto Rico, Jamaica, Hispaniola, and Cuba. Their paper is being published December 21 in the journal, Proceedings of the National Academy of Sciences.

Glor and Rabosky focused on species diversity -- the number of distinct species of lizards -- not the number of individual lizards.

"Geographic size correlates to diversity," said Glor. "In general, the larger the area, the greater the number of species that can be supported. For example, there are 60 species of Anolis lizards on Cuba, but far fewer species on the much smaller islands of Jamaica and Puerto Rico." There are only 6 species on Jamaica and 10 on Puerto Rico.

Ecologists Robert MacArthur of Princeton University and E.O. Wilson of Harvard University established the theory of island biogeography in the 1960s to explain the diversity and richness of species in restricted habitats, as well as the limits on the growth in number of species. Glor said the MacArthur-Wilson theory was developed for ecological time-scales, which encompass thousands of years, while his work with Rabosky extends the concepts over a million years. "MacArthur and Wilson recognized the macroevolutionary implications of their work," explained Glor, "but focused on ecological time-scales for simplicity."

Historically, biologists needed fossil records to study patterns of species diversification of lizards on the Caribbean islands. But advances in molecular methodology allowed Glor and Rabosky to use DNA sequences to reconstruct evolutionary trees that show the relationships between species.

The two scientists found that species diversification of lizards on the four islands reached a plateau millions of years ago and has essentially come to an end.

Glor said the extent and quality of the data used in the research allowed him and Rabosky to show that species diversification of lizards on the islands was not continuing and had indeed entered a state of equilibrium.

"When we look at other islands and continents that vary in species richness," said Glor, "we can't just consider rates of accumulation; we need to look at the plateau points."

Glor emphasizes that a state of equilibrium does not mean that the evolution of a species comes to an end. Lizards will continue to adapt to changes in their environment, but they are not expected to develop in a way that increases the number of species within a habitat.

Glor believes his work with Rabosky represents the "final word" on the importance of limits on species diversity over the rate of speciation when explaining the species-area relationship in anole lizards.


Story Source:

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


Journal Reference:

  1. D. L. Rabosky, R. E. Glor. Equilibrium speciation dynamics in a model adaptive radiation of island lizards. Proceedings of the National Academy of Sciences, 2010; DOI: 10.1073/pnas.1007606107

Cite This Page:

University of Rochester. "Environmental factors limit species diversity, lizard study finds." ScienceDaily. ScienceDaily, 29 December 2010. <www.sciencedaily.com/releases/2010/12/101220163248.htm>.
University of Rochester. (2010, December 29). Environmental factors limit species diversity, lizard study finds. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2010/12/101220163248.htm
University of Rochester. "Environmental factors limit species diversity, lizard study finds." ScienceDaily. www.sciencedaily.com/releases/2010/12/101220163248.htm (accessed April 24, 2014).

Share This



More Plants & Animals News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Monkeys Are Better At Math Than We Thought, Study Shows

Monkeys Are Better At Math Than We Thought, Study Shows

Newsy (Apr. 23, 2014) A Harvard University study suggests monkeys can use symbols to perform basic math calculations. Video provided by Newsy
Powered by NewsLook.com
Raw: Leopard Bites Man in India

Raw: Leopard Bites Man in India

AP (Apr. 22, 2014) A leopard caused panic in the city of Chandrapur on Monday when it sprung from the roof of a house and charged at rescue workers. (April 22) Video provided by AP
Powered by NewsLook.com
Iowa College Finds Beauty in Bulldogs

Iowa College Finds Beauty in Bulldogs

AP (Apr. 22, 2014) Drake University hosts 35th annual Beautiful Bulldog Contest. (April 21) Video provided by AP
Powered by NewsLook.com
805-Pound Shark Caught Off The Coast Of Florida

805-Pound Shark Caught Off The Coast Of Florida

Newsy (Apr. 22, 2014) One Florida fisherman caught a 805-pound shark off the coast of Florida earlier this month. Video provided by Newsy
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:
from the past week

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