Geoscience Reference
In-Depth Information
Table 5.2 ( Cont'd )
Category
Response
Indicator
Justification of indicator
c
t
w
Reduced availability
of leaves
Processing rates of leaves
and wood increase with
temperature. Floods in
winter cause more than
50% of leaf inputs to be
exported, leaving little
detrital material available
for invertebrate
consumption.
Share of the
feeding type
'shredder' in the
invertebrate
community
Benthic invertebrates are
routinely monitored in
most European countries.
If the availability of leaves
decreases, the share of
shredders will decrease,
too; in small headwater
streams, shredders should
typically account for
30%-40% of the
invertebrate community.
x
x
(x)
Replacement of cold
water species (fish,
macroinvertebrates)
Many fish and invertebrate
species in cold regions are
highly adapted to cold
water temperatures (cold
stenotherms) and vanish
with higher temperatures.
Water
temperature
(maximum
monthly values)
Physiologic barriers are
mainly determined by
extremes. For cold water
species, these are too
warm temperatures in
crucial phases of their life
cycle.
x
x
(x)
Increase or decrease
of species number
Low temperatures are a
migration and physiological
barrier for many aquatic
species. With temperature
increase, several species
can invade rivers in cold
ecoregions. In contrast, in
temperate and warm
regions, increasing water
temperatures lead to the
extinction of cold
stenothermic taxa.
Number of
species (e.g.
fish, selected
invertebrate
groups)
The increase of species
numbers is best evaluated
by a simple richness index,
e.g. the number of species
that can be easily inferred
from routine monitoring
results.
x
x
x
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