Influence of low flows on diversity and recovery of macrozoobenthos communities as one of the components of ecological status assessment
according to the Framework Directive. Jan Špaček and Pavel Hájek
• At the Magdeburg Seminar in Teplice we presented the problem of drying of small and medium streams focused on ecological status assessment.
• In years 2014‐2017 we met extremely low flow rates even at the large rivers.
• We focused on macrozoobenthos community changes.
Locality, methodology
• Elbe River – Decin• Elbe River – Valy
• Summer samples, low influence• Macrozoobentos• 3 minutes multihabitat sample • Years 2012, 2014 ‐ 2017
Elbe River ‐ Decin
• Partly natural watercourse• Stony and gravel shores• About 100 m widht (normal flowrates)
• About 70 m widht (low flowrates)
• Right site sample
Elbe River ‐ Valy
• Technically modifiedwatercourse
• Riprap and pavement shores• About 60 m widht (all flow rates)• Right site sample• influenced by the drainage of the weir in Prelouc
Physico ‐ chemical factors
• Temperature increase• pH and conductivity changes • Oxygen regime changes • Increasing nutrient and pollutant concentrations • Precipitation of metals on the surface of the substrate and organisms • The objective reduction of living space and number of microhabitats • Reduction of flow velocity • Siltation
Hydromorphological factors
• Flow size • Geological subsoil • Extent, scope and type of anthropic adaptations • Landscape type
Ecological factors
• Direct die‐off organisms • Predation increasing • Greater parasite development and easier transmission of diseases • Escape reactions• Rising of invasion species populations
Elbe River ‐ Decin
0
2000
4000
6000
8000
10000
12000
Děčín Děčín Děčín Děčín Děčín
2012 2014 2015 2016 2017
Non‐native species
Native species
Abundance
Elbe River ‐ Decin
3 4 46
9
38
2825 20
24
0
5
10
15
20
25
30
35
40
45
Děčín Děčín Děčín Děčín Děčín
2012 2014 2015 2016 2017
Native species
Non‐native species
Number of species
Elbe River ‐ Valy
0
100
200
300
400
500
600
700
800
900
Valy Valy Valy Valy Valy
2012 2014 2015 2016 2017
Non‐native species
Native species
Abundance
Elbe River ‐ Valy
2 3 3 39
25 2317
29
47
0
10
20
30
40
50
60
Valy Valy Valy Valy Valy
2012 2014 2015 2016 2017
Native species
Non‐native species
Number of species
Neogobius melanostomus – round goby
Elbe River ‐ Decin
Kolín
Obříství
Veletov
Týnec n.L.
Dikerogammarus villosus
Dikerogammarushaemobaphes
Corophium curvispinum
Corophium robustum
Jaera istri
Killer shrimp
Demon shrimp
Caspial mud shrimpDonau assel
Corbicula fluminea
Přelouč
Thank you for your attention!
