las comunidades de peces del río guadiamar y el accidente minero ...

Las comunidades de peces del río Guadiamar
y el accidente minero de Aznalcóllar
Results
Fish community
The following 9 native species were found in the study area: Southern Iberian barbel,
Luciobarbus sclateri (Günther 1868); Southern straight-mouth nase,
Pseudochondrostoma willcommii (Steindachner 1866); Calandino, Squalius alburnoides
(Steindachner 1866); Southern Iberian chub, Squalius pyrenaicus (Günther 1868);
Iberian arched-mouth nase, Iberochondrostoma lemmingii (Steindachner 1866);
Southern Iberian spined-loach, Cobitis paludica (de Buen 1930); European eel, Anguilla
anguilla (Linnaeus 1758); Thinlip grey mullet Liza ramada (Risso 1826) and Flathead
grey mullet, Mugil cephalus (Linnaeus 1758).
In addition, 5 exotic species were found: Carp Cyprinus carpio (Linnaeus 1758);
Prussian carp, Carassius gibelio (Linnaeus 1758); Pumpkinseed, Lepomis gibbosus
(Linnaeus 1758); Eastern mosquitofish, Gambusia holbrooki (Agassiz 1859) and
Largemouth bass, Micropterus salmoides (Lacèpéde 1802).
Native species
a) General models
Significant models were obtained for native species richness (S-na) and diversity (Hna),
which accounted for 70% (R 2 = 0.70) and 52% (R 2 = 0.52) of the variance,
respectively. The main factors included in the best models were similar for S-na and H-
na (Table 1). These models identified PCA4 (“Land use at the catchment scale”) and
“Number of reservoirs upstream” as the most influential factors. Variance partitioning
using hierpart showed that they accounted for 33% and 28% of the explained variance,
respectively, in the case of S-na; and 46% and 31%, respectively, in the case of H-na. A
positive relationship was found between PCA4 and both dependent variables, and this
means that higher native fish richness and diversity are found in natural forest areas
with respect to those with agricultural or urban land uses. In contrast, a negative
relationship with “Number of reservoirs upstream” was found, which indicates that the
more reservoirs upstream from a site, the lower the native fish richness and diversity.
“Drainage area” and PCA1 (“Habitat characteristics at the site scale”) were a second
group. These variables accounted for 20% and 19% of the explained variance,
respectively, for S-na. For H-na, “Drainage area” explained 23% of the variance. A
positive relationship with S-na and H-na was observed for “Drainage area”, which
simply reflects the species-area relationship that occurs as you go downstream: drainage
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