Chapter 1 - Núria BONADA

Chapter 3
but not for MedBasin and California. In northern hemisphere med-regions, common taxa have
a similar composition and abundance in each habitat independently of the region, especially in
pools. Riffles in MedBasin, although they are closer to the Californian ones, have a higher
variability in composition and abundance and are closer to SWAustralia and South Africa than
to lentic habitats of Med-Basin and California. However, for each region independently and all
taxa, MRPP results (Table 5) show that in studied sites all med-regions have significant
differences between the macroinvertebrate assemblage of riffles and pools. Number of taxa is
similar between R and L in all regions (Figure 11 and Table 8), but some differences are found
with the rest of metrics. EPT/OCH ratio is significant higher in R than L in all med-regions
except for South Africa (p>0.005) (Table 8). SWAustralia and South Africa have a significant
higher number of dipterans in R compared with MedBasin and California. Percentage of non-
insect taxa only displays significant differences among habitats in South Africa where a lower
number of non-insect taxa are observed in R than L.
number of taxa
number of diptera taxa
40
30
20
10
0
10
8
6
4
2
0
MedBasin
California
SouthAfrica
SWAustralia
MedBasinCalifornia
Plot 1
MedBasin
California
SouthAfrica
SWAustralia
MedBasinCalifornia
R L
SouthAfrica
SWAustralia
R L
SouthAfrica
SWAustralia
Figure 11. Box-Plot between riffles and pools for reference sites.
EPT/OCH taxa
% of non-insect taxa
18
16
14
12
10
8
6
4
2
0
60
50
40
30
20
10
0
114
MedBasin
California
SouthAfrica
SWAustralia
MedBasinCalifornia
Plot 1
MedBasin
California
SouthAfrica
SWAustralia
MedBasinCalifornia
R L
SouthAfrica
SWAustralia
R L
SouthAfrica
SWAustralia