How do Maxent calculate background pseudo-absences?

[Noam ben moshe]

Dear all,

1. can someone explain briefly about the way that maxent calculates pesudo-absences when only presence data is given?

2. In my study (distribution of rock hyraxes) I have only presence data. Can I improve the maxent predictions if I supply it with pseudo-absence data that I calculated by another program/code, designated for this purpose?

Many thanks in advance, 

Noam Ben-Moshe

[Sarah Sam]

Hi,

I can't answer question 1, but can confirm that you can improve your predictions by creating your own pseudoabsences.  I'm using a method called Target Group Sampling, described in the paper below.  If you refer to the sections on Background data and Sampling bias that should help :)

Merow, C., Smith, M.J. and Silander, J.A., Jr (2013), A practical guide to MaxEnt for modeling species’ distributions: what it does, and why inputs and settings matter. Ecography, 36: 1058-1069.  https://doi.org/10.1111/j.1600-0587.2013.07872.x

cheers,

Sarah