Chapter 1 - Núria BONADA

Regional amd local scale: convergences and divergences
community is highly similar between the northern hemisphere med-regions of California and
Med-Basin, with a 94% of similarity, while in the southern hemisphere there is an important
variability in the macroinvertebrates community. South African community is the nearest to
the northern hemisphere, sharing 65% of the taxa, while the Chilean area seems to be the less
similar. The two Australian med-regions have 35% of similarity with the South African,
California and Med-Basin communities, and 88% between them.
2
1
0
-1
Chile
California
MedBasin
SAustralia
South-Africa
SWAustralia
-2
-2 -1 0 1 2
Figure 3. NMDS Plot using Jaccard distance.
The unique and common taxa are variable between regions (Table 2), being South Africa the
region with a major number of unique taxa (13 families), followed by South Australia and
Chile, both with 11 taxa. California and SWAustralia have few unique taxa, although some
coldstenoterm plecopterans, as Peltoperlidae o Pteronarcyidae, are characteristic from North
America. The med-region of SWAustralia has a scarce unique community, and only the
caddisfly Plectotarsidae seems to be present in this area and absent in SAustralia. On the
other hand, South Africa and Chile has important unique taxa from a Gondwanic origin, as
Barbarochthonidae, Petrothrincidae and Hydrosalpingidae in South Africa and
Austronemouridae or Diamphinoidae in Chile.
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