MMDM and RPSV functions

questions concerning anlysis/theory using program DENSITY and R package secr. Focus on spatially-explicit analysis.

MMDM and RPSV functions

Postby Ulrike » Thu Nov 07, 2019 7:13 am

Hi,

I am trying to find out the exact formula which is used in secr for the MMDM and RPSV functions.

There are some references in the R help pages for these functions, but have so far not been able to locate the papers with the actual formula (eg I can't find the Otis book).
Another reference I found was Efford et al (2015), but from the secr webpage, I was not able to figure out which paper that is, that is what is the full title?
Can anyone help me with that?
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Re: MMDM and RPSV functions

Postby murray.efford » Thu Nov 07, 2019 3:43 pm

MMDM is of historical interest only, and the history starts with the Otis et al. 1978 monograph - you should really find that. I don't think they use 'MMDM' (but see the CAPTURE software). They say pp 72-73
"...an alternative approach is to base an estimate of W on animal movements as determined from recapture locations. Let ~W be such an estimate, for example one-half of the average maximum distance between trapped locations for all animals captured at least twice."

RPSV is defined in the help (?RPSV) if you go to the pdf as directed (or check https://www.otago.ac.nz/density/pdfs/secr-manual.pdf).

I am not aware of having published any paper in 2015.

Type MMDM or RPSV at the R prompt to see the code.
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Re: MMDM and RPSV functions

Postby Ulrike » Sun Nov 10, 2019 5:26 am

Thanks, I found the definitions for RPSV!

I am not sure right now, where I saw the reference to an Efford, 2015 paper, but if I find it, I will post here, since this is really odd.

For the MMDM, my question is basically what the maximum is of. I assume that the average refers to average across all animals (which were captured at least twice).
However, for the maximum, it is not clear from this phrase, whether it is
- for each animal the maximum distance between all pairs of locations where the animal ever was captured,
- or is it the maximum distance of locations between pairs of consecutive captures of the same animal

Possibly, the first one makes more sense.
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Re: MMDM and RPSV functions

Postby murray.efford » Sun Nov 10, 2019 5:37 am

Definitely the first one. MMDM is a sort of crude, biased estimate of home range diameter.
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