Figure 1.
Location of the 18 stream reaches in Denmark.
Natural streams (1–6); Restored streams (7–12); Channelized streams (13–18). UTM coordinates of the sites (UTM Zone 32, datum ED50). 1: Sunds Nørreå (N6231730; E496890), 2: Fjederholt (N6214415; E500939), 3: Linding (N6171439; E473283), 4: Gesager (N6190369; E543271), 5: Grydeå (N6243183; E471912), 6: Idom (N6243861; E468179), 7: Brøns (N6116409; E484998), 8: Lobæk (N6108125; E499423), 9: Surbæk (N6102701; E510372), 10: Jels (N6127631; E509606), 11: Gels (N6117435; E512790), 12: Lemming (N6233250; E532931), 13: Simmebæk (N6188424; E488854), 14: Fåre Mølleå (N6257940; E454624), 15: Madum (N6233919; E463860), 16: Hjortvad (N6137346; E494356), 17: Kongeå (N6141296; E519069), 18: Rejsby (N6121446; E483188).
Table 1.
Physical characteristics of the 18 streams.
Figure 2.
Relationship between stream bed slope and gravel coverage in the 3 stream types.
The solid regression line describes the relationship in natural streams.
Figure 3.
Relationship between stream bed sand coverage and substrate heterogeneity in the 3 stream types.
The solid regression line describes the relationship in natural streams and the dotted line is the fitted line for channelized streams.
Figure 4.
DCA ordination of macroinvertebrate communities in natural, channelized and restored stream reaches.
Environmental parameters significantly (Spearman rank correlation, p<0.05) correlated with in-stream physical characteristics are also shown.
Figure 5.
Number of threatened species and abundance according to stream type.
In total, 75 individuals of 9 threatened species were found in the 18 streams.
Table 2.
Macroinvertebrate community metrics in the three stream types.
Figure 6.
Relationship between substrate heterogeneity and macroinvertebrate community diversity for the 3 stream types.
The solid regression line shows the significant relationship in natural streams.