[R] Exponential population model

[David Winsemius]

> On Aug 29, 2016, at 7:06 AM, Msindai, Nadejda <n.msindai.09 at ucl.ac.uk> wrote:
> 
> Dear David
> 
> I think you misunderstood me, I need to find the name for an r package that models the population size from time 0 for a group of animals.  
> 
> I provided details to make it clearer the type of model I want to run. 
> 
> The only population model I have come across thus far is Popbio, which appears to be for plants? Therefore, can you assist me by telling me the name for a package that is used to model exponential growth: 
> 
> Exponential growth model is --
> ‪The exponential growth model assumes that the population starts out at time t=0 at some initial N(0), and growth at constant exponential rate r. If r>0 this results in theoretically unlimited growth over time.  The fundamental equation of growth is
> ‪ 
> ‪N(t+1)= N(t) exp®

(Thew HTML formating has turned ® into  trademark sign. (You are advised to post in plain-text._

If you had any data that model should be able to be fit with `glm` using a Poisson model. (No extra package if it were as simple as that, which it does not appear to be in the case.)

> 
> I do not have a known growth rate figure for my species, therefore, I plan to use life history data obtained from wild populations (of one particular species) to model the current population size for a group of animals introduced onto an island. 

So you have a population structure and an assumed death rate within age bands but you have no assumptions about birth rate. Seems that would not support any sort of growth model, yet. (This seems to be a typical demography exercise.)

https://www.google.com/search?q=r+growth+rate

And since you will be passing a hypothetical population through sections of different "mortality age x time cells" you will probably also want to run a search on "Lexis diagrams":

https://www.google.com/search?q=Lexis+diagrams+r+package

-- 
David.


> 
> Thank you for your help in this matter
> 
> Josephine 
> From: David Winsemius <dwinsemius at comcast.net>
> Sent: 27 August 2016 03:32:55
> To: Msindai, Nadejda
> Cc: r-help at r-project.org
> Subject: Re: [R] Exponential population model
>  
> 
> > On Aug 26, 2016, at 5:49 AM, Msindai, Nadejda <n.msindai.09 at ucl.ac.uk> wrote:
> > 
> > Dear admin
> > 
> > I am writing to ask for help with writing an R script to model the current population size using life history data (I do not know the intrinsic rate of increase (r)).
> > 
> > My study population are a group of introduced chimpanzees, that were released by the Frankfurt Zoological Society in 1966-1969 onto an island in Lake Victoria.
> > 
> > Thus I want to run a density independent population model using life history data, with 0 net migration/immigration (so this is a closed system).
> > 
> > 
> > These are the individuals entering the system (in my case arriving on the island), after 1969 no new animals arrive.
> > 
> > Year    1966    1966    1966    1966    1966    1966    1966    1968    1969    1966    1966    1966    1966    1968    1969
> > Animal ID       F1      F2      F3      F4      F5      F6      F7      F8      F9      M1      M2      M3      M4      M5      M6
> > DOB     1955    1955    1956    1957    1958    1959    1955    1960    1960    1958    1959    1959    1962    1960    1960
> > 
> > Notes:  Year is the year animal was released into the population
> >        F=female
> >        M=male
> >        DOB=date of birth
> > 
> > 
> > Using the following life history data I want to estimate the population size for the year 1979, 1989, 1999, and 2014, as well as future projection for 2019, 2029 etc.
> > 
> > Age at first birth for females: 11 years
> > Birth interval: 55.2 months
> > Age at last birth: 50 years (in 40-50 years only 47% of females have offspring)
> > Survival to 8 years = 67.7%(Female) 51.4%(Male)
> > Survival to 15 years 41%(Female) 27%(Male)
> > Survival 15-40 years 18%(Female) 11%(Male)
> > Survival 40+ years 7%(M/F)
> > 
> > 
> > 
> > Birth ratio set as ___M = Male, F = Female (set as 50:50)
> > 
> 
> This looks like a homework question and Rhelp is specifically announced as not doing homework. See the Posting Guide.
> 
> -- 
> David.
> > 
> > 
> > 
> > I hope you can be of help
> > 
> > Kind regards
> > 
> > Josephine
> > 
> > 
> > 
> > 
> >        [[alternative HTML version deleted]]
> > 
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> 
> David Winsemius
> Alameda, CA, USA

David Winsemius
Alameda, CA, USA