Diversity and Stability in Food-Webs

Posted by Roger Critchlow-2 on
URL: http://friam.383.s1.nabble.com/Diversity-and-Stability-in-Food-Webs-tp520801p520810.html



Tom Carter wrote:

>    But also, back to the original prompting email, I've just been  
> reading a fun little book -- "Ecological Orbits - How Planets Move  
> and Populations Grow" . . .  I recommend it (although I don't  
> necessarily agree with all of it).  The authors (Lev Ginzburg and  
> Mark Colyvan) are pushing for a transition beyond the Lotka-Volterra  
> regime of population modeling (their current fave is something they  
> refer to as "maternal effects").  They argue that it's time for a  
> "Newtonion revolution" in population modeling, largely in the sense  
> that they think we should start using second order difference /  
> differential systems in our (analytic) models.  For example,  
> classical Lotka Volterra, while nonlinear (with "quadratic" terms) is  
> still a first order system.  They argue that we should be looking  
> more at the second derivative of population (i.e., rate of change of  
> population growth rate) . . .

That's somewhat similar to Neo Martinez' messages about stability in
food webs.  First, as pointed out earlier, that empirical food webs
aren't the random webs that May looked at.  And second, on the nonlinear
issue, that the predator functional responses to prey densities aren't
linear.  Even a protist filter feeder can alter it's catch rate
considerably by simply swimming faster when there are more prey about to
catch.

-- rec --