Chapter 1 - Núria BONADA

Local scale: Distribution patterns in Trichoptera
reaches of rivers (k-means 3 and 4), characterized by intermediate altitude and channel width
and lower riparian structure. Conductivity is also similar between both midstream groups
although the higher percentage of sedimentary basins mainly composed by marls in group 3
and the dominance of pools with a lower IASPT, suggest us to consider it as a group
of samples with rambla type features. In contrast, group 4 would correspond to common
GROUP 1: CALCAREOUS/SILICEOUS HEADWATERS
Calcareous and siliceous basin with a small area. Medium altitude.
Low stream order and narrow channel. High biological quality and
riparian structure. Riffles dominant with low substrate diversity
and high heterogeneity elements. Water with low conductivity.
GROUP 2: SILICEOUS HEADWATERS
Mainly siliceous basins with small area. High altitude. Medium
stream order and narrow channel. High biological quality and
riparian structure. Riffles dominant with high substrate diversity
and heterogeneity elements. Water with very low conductivity.
GROUP 3: SEDIMENTARY-MARLS MIDSTREAMS
Mainly sedimentary-marls basin with medium basin area. Mediumlow
altitude. High stream order and narrow channel. High biological
quality and medium riparian structure. Low IASPT. Pools dominant
with medium substrate diversity and scarce heterogeneity elements.
Water with high natural conductivity.
GROUP 4: CALCAREOUS/SEDIMENTARY MIDSTREAMS
Calcareous and sedimentary basin with large basin area. Mediumlow
altitude. Medium stream order and narrow channel. High
biological quality and medium riparian structure. Medium IASPT.
Riffles and pools dominant with medium substrate diversity and
heterogeneity elements. Water with high conductivity.
GROUP 5: CALCAREOUS/SEDIMENTARY LOWLAND REACHES
Calcareous and sedimentary basins with very large basin area. Low
altitude. High stream order and wide channel. Low biological quality
and riparian structure. Riffles and pools dominant with medium
substrate diversity and scarce heterogeneity elements. Water with
high conductivity.
Figure 7. Groups significance according to the results obtained from discriminant analysis.
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