Immediate effect
We added two substrates to each stream to test the immediate effect of
the disturbance on the communities. After 21 days, we collected an
experimental unit and subjected another to a disturbance. The 21-days
interval was previously reported as enough for the establishment of a
stable aquatic insect community (Landeiro et al. 2010, Godoy et al.
2016). The disturbance was an instantaneous increase in water flow using
a water pump from a 60 cm distance upstream. The increased water flow
for this experimental unit was
60m3.hour-1 for 10 minutes. To test
the immediate effect, we collected the AS right after the disturbance.