What about adding something of the same yellow colour or alike to the bases as well, so there is a connection between the army camouflage colour and their surroundings?
[EDIT] I just had a closer look at your pictures and not sure if its the light or my screen but is the flock yellow-ish, sand colour or grey?
So, the Zamesi desert (yellow) does fool the eye to connect the base color with a more natural army desert camouflage look. I wasn't going for camouflage though. I was going to an original tau sept color scheme with only a switch on the Tau light ochre color (orange). Armor shading done with Skrag brown
The room was a little dark and it was late. So I did increase the brightness with my cameras light setting a little to try to best capture how maximum detail. The light came from a ceiling fixture so I know that the light source doesn't produce a true white light. This can distort pictures slightly. I think I captured the colors pretty accurately though. The bases have a 'gray ash' material. The brand was The Army Painter. I prepainted the base skavenblight dinge (grey) to help the grey ash appear more consistent in case any spots on the base top are missed. If any spots were a little bare, it wouldn't look so funky. I haven't really done my homework on doing bases actually, so I figured grey ground was a safer option. I totally winged it on doing the bases though. I didn't want to go sand color for the base because I was afraid it may make my figures not stand out so much. I didn't use green grass like bases because I didn't know if it would distract from the model detail.