Diversity of Sericostomatidae (Trichoptera) caddisflies in the Montseny mountain range

Abstract

Biodiversity is under threat by the ongoing global change and especially freshwater ecosystems are under threat by intensified land use, water abstraction and other anthropogenic stressors. In order to monitor the impacts that stressors have on freshwater biodiversity, it is important to know the current state of ecosystems and species living in them. This is often hampered by lacking knowledge on species and genetic diversity due to the fact that many taxa are complexes of several morphologically cryptic species. Lacking knowledge on species identity and ecology can lead to wrong biodiversity and stream quality assessments and molecular tools can greatly help resolving this problem. Here, we studied larvae of the caddisfly family Sericostomatidae in the Montseny mountains on the Iberian Peninsula. We expected to find cryptic species and that species would not occur in syntopy due to different ecological niches. We sampled 44 stream sites and sequenced 247 larval specimens for the barcoding region of the mitochondrial cytochrome c oxidase gene. A modeling approach was used to assess the bioclimatic preferences of the found species. Two molecular groups were identified. One could be assigned to Schizopelex furcifera and one to Sericostoma spp. We did find both taxa in syntopy in >50% of sampling sites and could show that the taxa prefer similar bioclimatic conditions. A reexamination of larval specimens showed that Sericostoma and Schizopelex larvae could not be unambiguously identified to the genus level. Overall, our results show the importance of including molecular tools into biodiversity assessments in order to correctly identify the species diversity of a region and to prevent wrong assessment results.