Professor Rodríguez-Iturbe discusses new fish diversity model
Posted May 7, 2008; 12:55 p.m.
This interview is based on a paper published in the journal Nature on May 8, 2008. Read more
Video Closed Captions
I am a hydrologist, which basically means that I deal with the movement
of water in landscapes.
The dynamics of water have a commanding effect on the biodiversity
of fish in river networks.
River networks are fractals. And fractals are this type of mathematical
construct in which the parts and the whole cannot be distinguished
from one another. River networks are fractals. Lightning is fractal.
Trees are fractals. Clouds are fractals.
To the untrained eye they may look very different but there is an
enormous amount of unity in this infinite diversity.
In a river basin the channel network fragments the space. And its character
as a fractal implies, among other things,
that the laws that govern the structure of that network are the same
regardless of whether the river basin is small or large
or is in Venezuela or is in the United States or is in Africa. It is very
different than in a savanna.
In a savanna -- seeds, animals, people move through a space that is
What we have done, really, is a mathematical model implemented in
We merged different sets of existing data from the Mississippi-Missouri
river basin. It is a fantastically simple model.
But it predicts wonderfully well all of the biodiversity characteristics that
we are interested in studying.
From the practical side, it provides us a link to the changes in biodiversity
one can expect from external things like climate change.
Another aspect is the impact that manmade structures like dams will
have in biodiversity.
From the science point of view, river basins are crucial depositories of
biodiversity, of energy resources, and human populations.
We need to understand how the different dynamics that act on them
influence each other.