I am leaning towards presuming that a conservation_status entry of Nan means that the species is not threatened.
However, I am uncertain about my above statement after finding that the highest number of observations for the ‘Species of Concern’ category is 268, while the lowest number of observation for the Nan category is only 9 and what’s worse is that quite a lot of the other observations in this Nan category are lower than 268. Two conclusions I can make regarding a species in the Nan category which has a low number of observations :
It doesn’t mean it’s not threatened but rather that it was overlooked when classifying the conservation status or the data is simply not available and it is not a good idea to include the conservation status variable in the analysis.
The number of observations is not the criteria for declaring a species conservation status but also other variables not included in the current dataset.
What does everyone else think? Or is there an expert that can give us a definitive answer?