Fig. 4

Fitted species abundance distribution (SAD) curves of polar soil microbial communities between the Vestfold Hills and Windmill Islands. The bars represent the mean proportion of species at each site in different octave classes of abundance. The blue and orange lines show the mean of fitted values from region-by-region fits of the Poisson-lognormal (PLN) and negative binomial (NB) distributions to the data, respectively. A PLN-fit best explains the overall structure of these communities, particularly for bacterial communities at the Windmill Islands. Eukaryotic and archaeal communities demonstrate slightly weaker PLN-fits and multimodal distributions across both regions, suggesting the emergence of neutrality