Current projections predict an intensification of hydrological drought as a consequence of climate change, but we know very little about the potential effects on aquatic communities. Our work on La Baña (SW León Province, Spain), a mountain lake suffering from increased water seepage due to geological reason, assessed the effect of drought on the littoral macroinvertebrate community. The most relevant change was a drop in richness values: rarefaction curves showed that richness in lake in 2014 was only slightly higher than in the temporary pond, and much lower than in the lake in 2005 or 2006. However, the assemblage composition did not shift towards a fauna typical of temporary waterbodies. These results might indicate that the resistance of the assemblage was high enough to prevent changes in the first moments (differences between 2005 and 2006 were small), but not after nine years of sustained summer drought.