Changes in global climate could disrupt the annual cycle of filling and drying to which this community has evolved. Previous misconceptions assume that all rock pools are temporary habitats. We have shown that several pools over a period of 3 years have maintained constant wetted conditions. These “permanent” pools (Tinajas) are shaded within deeply incised channels. Tinajas are cut into the sandstone bedrock by torrential flows during summertime cloudbursts.  There are also many temporary pools that fill and dry in 2-16 days.  Predators (Notonectidae, Dytiscidae, Hydrophilidae, and Gyrinidae) were most abundant in the permanent pools, whereas fairy shrimp (Branchinecta packardi) and a biting midge (Dasyhelea sp.), were most abundant in the temporary pools.  By examining rain events for the last ten years, we found that temporary pools are filled, on average, 7.4 times a year.  Interestingly, we also found that there are approximately 1.5 rain events per year that can completely scour all species from the permanent pools.  Flight (e.g. Chironomidae and Ceratopogonidae) was 3.5x greater in the upstream direction consistent with Müeller’s recolonization hypothesis. Species composition in rockpool metacommunities was not only affected by pool permanency but also by annual scouring events and dispersal.