| Thirty three lotic environments in the Yungas mountain cloud forest of NW Argentina were sampled both in undisturbed forest areas and sites altered by human activities. Aquatic insects of 143 taxa in 55 families were collected. Cluster analysis suggested altitude as one of the main structuring variables of aquatic insect communities in these streams, and its importance was confirmed by non-metric multidimensional scaling (NMS); the environmental parameters measured that were best correlated with the ordination were altitude, water temperature, latitude and channel variables (width, percentage of large and small woody debris, of undercut banks, cobble and coarse gravel). Multi response permutation procedures (MRPP) showed streams in well preserved areas to... |
