R help - Jan 2011 - stochastic models for population growth

Hello,
Having measured two populations' characteristics at one particular time[with
great precision] with R, I would like to extend this to measuring the same
populations starting at t1, and then again at t2, and try to develop a growth
model (something like dpop1/dt=r*pop^(...),dpop2/dt=r*pop^(...)). I think the
idea is to create a model that will predict the growth of a population(N(mu,
sigma)) within a margin of error. This kind of modeling isn't well known or
publicized in terms of R, am I right?
regards,
s

It's not too clear to me what you plan to do.
You want to model population growth using a normal distribution?

You should consider the classic differential equation of population growth
and look at variants with species interaction.

For modeling a single species you want to have

dP/dt = r*P (r is rate of increase accounting for birth and death)

which is P(t)=c1 e^(rt)
(c1 you solve from your initial conditions)

Then you can look to add a N(0,s) random component for


If you want to do some competition for resources/predator-prey modeling
there's already lots done on those.

As far as an R library you can download and just enter a few parameters...
I'm sure there's something in:
http://cran.r-project.org/web/views/Environmetrics.html


Michael D

On Thu, Jan 20, 2011 at 23:57:18 -0800 (PST), Vassily Shvets <
shv736_at_yahoo.com<shv736_at_yahoo.com?Subject=Re:%20[R]%20stochastic%20models%20for%20population%20growth>
>wrote:
>
> Hello,
> Having measured two populations' characteristics at one particular
> time[with great precision] with R, I would like to extend this to measuring
> the same populations starting at t1, and then again at t2, and try to
> develop a growth model (something like
> dpop1/dt=r*pop^(...),dpop2/dt=r*pop^(...)). I think the idea is to create a
> model that will predict the growth of a population(N(mu, sigma)) within a
> margin of error. This kind of modeling isn't well known or publicized
in
> terms of R, am I right? regards,
> s
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