Chapter 1 - Núria BONADA

SPATIAL HETEROGENEITY
PERMANENT
riffle species
pool species
core species
riffle species
pool species
core species
wet dry
r+K
No significant species traits
INTERMITTENT
riffle species
pool species
core species
pool species
core species
wet dry
K
TEMPORAL HETEROGENEITY
EPHEMERAL
riffle species
core species
wet dry
Local scale: Habitat and temporality effects
r
Life cycles < 1 year
Less reproductive / ea r
Larvae important
Passive dipersal (aquatic forms)
Respiration by gills or tegument
Locomotion: substrate attatchment
Figure 8. Application of permanent, intermittent and ephemeral conditions to the “River Habitat
Template” from Townsend & Hildrew (1994).
Concluding remarks
Mediterranean streams are known for their flow fluctuations along and between years that
may cause, mostly in summer, very deep changes in environmental conditions (Gasith & Resh,
1999). Although a different macroinvertebrate assemblage is observed between seasons in all
sites (Figure 4), more fine information can be obtained with the categorization of sites in
permanent, intermittent and ephemeral. Temporary changes in mediterranean rivers have
been related to the climate (e.g. Gasith and Resh, 1999), but other factors may influence and
increase or decrease its importance. In our study, either climate or geomorphology of the area
sampled interferes on the temporality of rivers and macroinvertebrate responses, providing
heterogeneity on responses at different scales. In mediterranean rivers, all these factors can
have important consequences in designing of biomonitoring programs in these areas, and
methods adapted to these areas have to be developed and tested (Bonada et al., Chapter 1).
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