Fig. 1

First two dimensions of the principal components analysis of the weighted Unifrac distances. Light grey and dark grey circles represent koalas located in manna gum and messmate forest respectively. With the corresponding 90% ellipses shown (ellipses were calculated assuming a multivariate t-distribution from 7 samples from 5 koalas captured in manna gum forest and 12 samples from 8 koalas, including donor koalas, located in messmate forest). Treatment koalas are shown in red, while, control koalas are shown in blue. Open diamonds represent the koalas’ GI microbiomes at capture (with the exception of one treatment koala where the capture sample was not available and instead the sample prior to messmate introduction was used, indicated by the *), while closed diamonds show the koalas’ GI microbiomes at the conclusion of the experiment (except for the control koala released early for which their final sample, 9 days after inoculation is shown; indicated with the *). Lines join points from the same captive koala with the direction their GI microbiomes shifted over the experiment indicated by arrows. Dark purple circles indicate the GI microbiomes of the treatment donor koalas for cohort 1, while, pink circles indicate those for cohort 2. Very light green, light green, medium green and dark green squares indicate the bacterial, coarse, solute and fine layers respectively. Light purple squares indicate the inoculum