December 21, 2012
Victorian-Era Map Helps Researchers Redraw Distribution Of Biodiversity
Brett Smith for redOrbit.com - Your Universe Online
Ecologists have collected massive amounts of data over the past 130 years and a research team led by University of Copenhagen scientists has used that wealth of information to redraw a Victorian map used to illustrate the geographic distribution of animals.
The original map by the renowned English naturalist Alfred Russel Wallace, with assistance from Charles Darwin, has been in use since it was drawn up in 1874, when it established the foundation for global biodiversity.
Based on evolutionary and geographical data for over 20,000 birds, amphibians, and mammals, the new map expands Wallace´s six geographic regions to 11 and explains how they are all interrelated to each other.
"Our study is a long overdue update of one of the most fundamental maps in natural sciences. For the first time since Wallace´s attempt we are finally able to provide a broad description of the natural world based on incredibly detailed information for thousands of vertebrate species,” said co-author, Ben Holt from the University of Copenhagen´s Center for Macroecology, Evolution and Climate.
The team set out to incorporate not just the distribution of species into their map, but the family tree of inter-species relationships. This additional approach was an attempt to recall the evolutionary character of Wallace´s original map.
Using computer models, the team divided the dry land around the globe into squares on a grid and analyzed the species distribution from the three vertebrate groups for each square shared, along with that square´s relationship to its neighbors.
The computer models revealed that analyzing birds placed a new boundary largely along Wallace´s previous line. However, adding in the new information on mammals and amphibians shifted the line.
The new map showed how many regions in the Southern Hemisphere, including Australia, Madagascar and South America, have an abundance of unique animal communities. Conversely, the diversity of life above the equator is more homogeneous. The scientists said the relative isolation, unique habitats, and tropical climates of these regions fueled a wider variety of life.
Data for reptiles, plants or insects wasn´t included in the new map due to a lack of information, but the scientists said those data can be easily incorporated in future iterations.
“The map provides important baseline information for future ecological and evolutionary research. It also has major conservation significance in light of the on-going biodiversity crisis and global environmental change,” said co-author Jean-Philippe Lessard, who is currently based at McGill University in Canada.
“Whereas conservation planners have been identifying priority areas based on the uniqueness of species found in a given place, we can now begin to define conservation priorities based on millions of years of evolutionary history,” he added.
The concept of regional mixes of animals fascinated 19th century ecologists who were in the throes of developing a theory of evolution via natural selection. They noted at the time that distant, yet similar habitats didn´t support the same fauna.
The University of Copenhagen study was published today in the journal Science Express.