pcountOpen to model stage structured populations?

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Tati Micheletti

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Nov 14, 2023, 2:55:23 PM11/14/23
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Dear all,

I am pretty new to unmarked, so I really appreciate any suggestions. I have repeated counts (n = 8) for a seabird species through time (approximately 2 years between the first and the last surveys), across several breeding sites (n = 9), identifying adults, number of nests with eggs, and chicks in five different development stages. I was wondering if the extension to the open N-mixture model (Dail and Madsen 2011) for structured population developed by Zipkin et al., 2014 has been implemented in unmarked? If not, is my only solution to run the model "manually" with R + JAGS (as was done in the paper)? Or is there any other model anyone could suggest for my case? 

Thanks a lot in advance!

Cheers, Tati

Marc Kery

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Nov 14, 2023, 3:11:37 PM11/14/23
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Dear Tati,

no, you can't do this with unmarked. You have to go "more flexible", or "custom", which in practice almost always means "go Bayesian".

You seem to have a lot of data and thus I feel some sort of integrated population model would really be best for you. But the choice of model depends on the goals of your modeling and your questions. So what exactly is it you want to learn from your model ?

Best regards --- Marc


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Subject: [unmarked] pcountOpen to model stage structured populations?
 
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Tati Micheletti

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Nov 14, 2023, 3:27:31 PM11/14/23
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Dear Marc,

Nice to hear from you, and thank you for the quick reply. I took your course in 2015; it helped me finish my PhD. =)

I am trying to understand the effects of rat eradication on population growth (i.e., trends) of different species on an island. I managed to model other species (a lizard, a crab, and a small bird), for which there are only adult counts. In those cases, I used pcountOpen. However, I have richer data on seabirds (i.e., with different life-stages) and was wondering what would be the best model for it. Honestly, I am not interested (at this point, at least) in learning too much about the population itself, and I would refrain from going down the IPM road if I could -- not that I don't find it interesting or useful, but this is just a side project for which I have very limited time, and the goal at the moment is just to see if the eradication had any effect on population growth. I even considered just lumping all individuals from the different stages, and using pcountOpen, but I wonder if I will be breaking any important assumptions. Thoughts?

Thanks a lot!

Cheers, Tati



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Marc Kery

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Nov 23, 2023, 2:34:36 AM11/23/23
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Dear Tati,

 

given your interests and time constraints, I’d go for the simple Dail-Madsen approach which you can do in unmarked. Adult counts summarize the whole demography after all, so if rat eradication has an important effect anywhere in the life-cycle, then that ought to show up eventually in the counts of the adults.

 

Best regards  --- Marc

 

 

 

Tati Micheletti

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Nov 23, 2023, 3:08:42 AM11/23/23
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Dear Marc,

Thanks a lot for the answer. After giving it some thought last week, that's exactly what I ended up doing: only adult counts with Dail-Madsen's model using unmarked. It's great to have expert thoughts on this.

Thank you very much!

Best regards,

Tati
---------------------------------------------------------------------------------------
Tatiane Micheletti, Ph.D.
Research Associate - UBC / Pacific Forestry Center, Canada
Guest Scientist at TU Dresden
Ph.D. in Forest Zoology - TU Dresden, Germany
Master in Sustainable Tropical Forest Management
TRÍADE - Brazilian Institute for Conservation Medicine
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