Morphological traits and vertical distribution of hyporheic chironomid larvae in Atlantic Forest streams

Hyporheic zone is an active ecotone constituted by the interstitial spaces between the particles of the riverbed. The use of morphological traits can be useful to detect organisms distribution patterns in these areas. Information concerning hyporheic communities are scarce as well on chironomid vertical distribution. Fauna samples from the hyporheic zone were collected at three depths and in four microhabitats. Eighteen genera were recorded and 13 morphological traits were identified. The results indicate that the distribution patterns of hyporheic chironomid taxa vary according to depth and microhabitat. Spatial preferences for riffles habitats are evident, and the vertical distribution is correlated with morphological traits like body size, pseudopods and mentum. Faunal abundance and richness decreased with depth and the vertical distribution influenced the chironomid morphological traits. We conclude that the use of morphological trait can introduce new useful information about the distribution of hyporheic fauna. http://zoobank.org/urn:lsid:zoobank.org:pub:E1DDF958-AA8C-40FD-A0D5-F281AA4AEA04