184
H. Hoang' F. Recknagel. J. Marshall . S. Choy
Figure 9.3b represent unimodal curves on optimal temperature conditions for
physiological processes such as ingestion and reproduction rates of several
Daphnia species extracted from laboratory experiments as summarized in Lampert
and Sommer (1997). It shows that a decrease in physiological activity rates above
the maximum is usually more rapid than the increase in the rates at sub-optimal
temperature. A similar shaped sensitivity curve was discovered for the relationship
between Cladocera occurrence and water temperature (Figure 9.3a) that indicated
a similar optimum temperature range from 10 to 30"C as in Fig. 9.3b.
Baetidae are known to be common in dear, cold streams (Suter 1996). They
belong to the mayflies that emerge first in spring and may occur on warm days in
late winter. In Queensland, Baetidae was observed in southem parts but never
found in tropical areas. Hawking & Smith (1997) characterise Baetidae as fast
swimmer where their nymphs prefer deep habitat. The sensitivity curves in Fig.
9.4 indicated these relationships very weIl.
a
b
0.8
0.8
GI
~0.6
GI
~0.6
i
i
1110.4
~0.4
III
0.2
~
0.2
0
0
0
5
10 15 20 25 30 35
0
0.5
1.5
Water Temperature (oC)
Habitat Depth (m)
Figure 9.4. Relationships of Baetidae with a) water temperature and b) water
depth as discovered by sensitivity analysis.
Chironomids (midge larvae) tend to be highly abundant in freshwater
ecosystem such as streams. The two subfamilies Tanypodinae and Orthocladiinae
were monitored in Queensland streams. Orthocladiinae are known for their coldstenothermic nature that makes them abundant in subalpine and mountain streams,
where maximum water temperatures in summer reach 100e. In middle and
lowland streams, where water temperature may exceed 20°C, the abundance of
Orthocladiinae decreases significantly (Lindegaard and Brodersen 1995). The
sensitivity curves in Fig. 9.5 indicated the preferred occurrence of Orthocladiinae
at upper stream reaches (Fig. 9.5a) and cold water (Fig. 9.5b).
H. Hoang' F. Recknagel. J. Marshall . S. Choy
Figure 9.3b represent unimodal curves on optimal temperature conditions for
physiological processes such as ingestion and reproduction rates of several
Daphnia species extracted from laboratory experiments as summarized in Lampert
and Sommer (1997). It shows that a decrease in physiological activity rates above
the maximum is usually more rapid than the increase in the rates at sub-optimal
temperature. A similar shaped sensitivity curve was discovered for the relationship
between Cladocera occurrence and water temperature (Figure 9.3a) that indicated
a similar optimum temperature range from 10 to 30"C as in Fig. 9.3b.
Baetidae are known to be common in dear, cold streams (Suter 1996). They
belong to the mayflies that emerge first in spring and may occur on warm days in
late winter. In Queensland, Baetidae was observed in southem parts but never
found in tropical areas. Hawking & Smith (1997) characterise Baetidae as fast
swimmer where their nymphs prefer deep habitat. The sensitivity curves in Fig.
9.4 indicated these relationships very weIl.
a
b
0.8
0.8
GI
~0.6
GI
~0.6
i
i
1110.4
~0.4
III
0.2
~
0.2
0
0
0
5
10 15 20 25 30 35
0
0.5
1.5
Water Temperature (oC)
Habitat Depth (m)
Figure 9.4. Relationships of Baetidae with a) water temperature and b) water
depth as discovered by sensitivity analysis.
Chironomids (midge larvae) tend to be highly abundant in freshwater
ecosystem such as streams. The two subfamilies Tanypodinae and Orthocladiinae
were monitored in Queensland streams. Orthocladiinae are known for their coldstenothermic nature that makes them abundant in subalpine and mountain streams,
where maximum water temperatures in summer reach 100e. In middle and
lowland streams, where water temperature may exceed 20°C, the abundance of
Orthocladiinae decreases significantly (Lindegaard and Brodersen 1995). The
sensitivity curves in Fig. 9.5 indicated the preferred occurrence of Orthocladiinae
at upper stream reaches (Fig. 9.5a) and cold water (Fig. 9.5b).