G. fossarum is common in smaller streams in prealpine areas and
mainly occurs in upstream areas [32], leading to potentially highly
isolated populations. G. fossarum may occur in extremely high
population densities, frequently representing the most abundant
macroinvertebrate in streams of our study area (own observations).
However, G. fossarum may be threatened by extinction locally, for
example due to pollution [33]. Previous research has shown that
G. fossarum represents at least three cryptic species