R2ucare help

questions concerning analysis/theory using programs M-SURGE, E-SURGE and U-CARE

R2ucare help

Postby melisacbl » Mon Apr 30, 2018 1:41 pm

Hello there,

I'm trying to use R2ucare to identify heterogeneity in survival or capture probabilities in my data because I want to analyse it with Pollock's RD. I have 42 individuals, 3 primary sampling occasions, and 34 secondary sampling occasions. Am I right to believe that I should pool the encounter histories into the 3 primary occasions and before analyzing it with R2ucare? I did that in R and had errors for test2ct (Error in m[rw, cl] : subscript out of bounds) and test2cl (Error in rep(NA, km4) : invalid 'times' argument) and I don't know why... does the analysis not work for 3 sampling occasions? The analysis worked for test3sr:
Code: Select all
stat        df     p_val sign_test
        0         1         1         0

$details
  component stat p_val signed_test test_perf
1         2    0     1           0    Fisher


and test3sm:
Code: Select all
$test3sm
 stat    df p_val
    0     0     1

$details
  component stat df p_val test_perf
1         2    0  0     0      None


but I'm not sure if it actually worked...

I am very new to MARK and CMR analysis. I'm basically self-taught (since January this year) via the MARK manual and relevant research papers so any help/advice you have will be highly appreciated!
melisacbl
 
Posts: 1
Joined: Fri Apr 27, 2018 3:12 pm

Re: R2ucare help

Postby Guillaume Souchay » Wed May 02, 2018 5:55 am

Hi,

I think you may be in a special case because you need at least 3 primary occasion to be able to estimate survival and recapture rate, and it may be quite difficult to investigate temporal effect with such a low number of primary occasion. Remind that even with a Robust-design model, survival is estimated between primary occasion, so you will only have 2 survival estimates.
For the RD, yu should be able to compute a median c-hat with MARK. If you want to use U-CARE or R2Ucare, you will have to pool all the observations of secondary occasion. This will lead to 2 estimates of survival, 2 estimates of recapture and only 42 individuals. It may be quite difficult to estimate individual heterogeneity in your case.

Best wishes,
Guillaume
Guillaume Souchay
 
Posts: 61
Joined: Wed Feb 27, 2008 5:20 am
Location: Nantes, FRANCE


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