I am using SDMtoolbox to examine the importance of different environmental variables associated with invasive bird distributions. I am focusing on permutation importance as an indication of the relative importance of each variable.
I have run “MaxEnt: Spatial Jackknifing” through ArcMap for sixteen separate species. I am performing spatial jackknifing with 3 spatial groups, using bias files, and using automatic settings for the regularization multiplier. For each species, I have run the model multiple times to make sure that I am consistently getting the same permutation importance results each time. For the species with larger numbers of points, I have indeed been getting the same permutation importance values each time I run the model with the same parameters multiple times. However, for some of the species with fewer points, I have been getting very different values for permutation importance for each run. In other words, MaxEnt is giving me very different permutation importance values if I run the same model (with the same species, same environmental variables, and same parameters) multiple times. The sizes of the datasets for which I have been having this problem range from 27 points to 353 points. I used the spatial rarefication tool to spatially rarefy all of my presence data.
I was hoping someone could give me some insight into why I might be experiencing this problem. I am happy to provide more information. I am a newbie to Maxent and SDMtoolbox, so I apologize if this issue is due to a silly mistake or misunderstanding on my part.