Name of parameters (multi-season two-species models)

[Estevo]

Hello everyone.

I`m running multi-season co-occurrence models (i.e. two-species) on Presence but I`m having some problems on finding information regarding the extinction parameters when I use the PSIBa/rBa parameterization. For instance, I could find the definitions for the following parameters at the Presence help file (http://www.mbr-pwrc.usgs.gov/software/doc/presence/presence.html#ms2sp): εAB; εAb; εBAA; εBAa and εBaa. However, when you check the design-matrix, there`s a sixth parameter (εBaA) which I couldn`t find its definition. Any thoughts on what it means?

Thanks in advance,

Cesar

[jhines]

Hi Cesar,

It looks like I missed that one in the documentation.

The first character, 'B', after the ε refers to the species which went locally extinct between seasons. The next two characters specify the status of the other species at the previous and next seasons. So,
εBaA means species B goes extinct between seasons i and i+1 (uppercase b), and species A was not present at season i (lowercase a), but was present in season i+1 (uppercase A).

The same notation goes for the colonization parameter, γ.

[Estevo]

Thanks for your help Jim, specially for your explanation.

Cesar