Original paper

Short-term colonization patterns of macroinvertebrates in alpine streams

Zbinden, Marlè ne; Hieber, Mä ggi; Robinson, Christopher T.; Uehlinger, Urs


We examined the short-term colonization of habitat patches by larval macroinvertebrates in 6 different types of alpine streams, including permanent kryal (glacier-melt), rhithral (rain and snow-melt), and krenal (groundwater) streams, kryal and rhithral lake outlets, and temporary rhithral streams. Abundant macroinvertebrates found in the different streams were common alpine species, although taxon richness, invertebrate density, and Simpson's diversity were highest in krenal and rhithral streams and lowest in kryal lake outlets. Cages filled with natural substrata were placed in riffle/run habitats in each stream and replicate cages were subsequently collected after 3, 8 and 30 days during early summer. Benthic and drifting invertebrates also were collected to compare with cage assemblages at each stream. Colonization of cages was rapid at most sites with high total densities and biomass occurring within 3 days. Simpson's diversity was highest on day 3, and decreased and stabilized by day 8 in all stream types. Chironomids, simuliids, and the mayfly Baetis alpinus were common early colonizers of cages at most streams. The turbellarian Crenobia alpina was a common colonizer of cages in temporary rhithral streams, and heptageniids were most common in rhithral stream cages. Chloroperlids were common colonizers of cages in krenal and kryal streams, and trichopterans were most common in cages of permanent krenal and temporary rhithral streams. Less common and rare taxa were late colonists of cages, having highest densities by day 30. The similar colonization patterns observed among alpine stream types may reflect altitudinal constraints on the regional species pool.


lake outletraritytemporary streammayflyoligochaeta