Ecology and vegetation of braided rivers in the European Alps with special emphasis on the Tagliamento - King of alpine rivers

Transcription

1 Ecology and vegetation of braided rivers in the European Alps with special emphasis on the Tagliamento - King of alpine rivers Norbert Müller University of Applied Sciences Erfurt, Germany 1

2 Contents 1 Geography of the European Alps 2 History of the European Alps 3 Ecology of alpine rivers in Europe 4 Human impact on alpine rivers 5 Tagliamento - the last large natural river in the European Alps 5.1 Morphology and vegetation 5.2 Plant diversity 5.3 Diversity of key species and exotic plants 5.4 EU Habitats and importance for nature conservation 6 Risks for the Tagliamento 7 Challenges and chances for the future 2

3 1. Geography of European Alps 3

4 Venecia 4

5 Geology Central Alps (< 4000 m) - Silicious (origin volcanic) Northern & South. Alps (< 3000 m) - limestone (origin sea sediments) 5

6 History BC end of glaciers period 6

7 2 History BC first records of burning forests and creating new pastures in the Southern - and Central Alps BC increasing of permanent settlements in the valleys - 0 Via Claudia permanent road from the Romans across the Alps AC main period - transformation alpine forests in meadows 7

8 8

9 3. Ecology of alpine rivers in Europe 9

10 3.1 River types 10

11 3.2 Hydrodynamics Annual run-off regime of a lowland and an alpine river in Europe 11

12 3.3 Dynamics in morphology Catchments areas in limestone are the main sources for the bed loads which are transported during flood water events 12

13 When the flood water event is over the landscape has changed. 13

14 ..for the design of islands the debris can play an essential role 14

15 3.4 Dynamics and structure of floodplain vegetation Spatial and temporal dimension: example for patch dynamics

16 3.4 Dynamics and structure of floodplain vegetation Bare & Pioneer vegetation Key species: Epilobium div. spec., Myricaria germanica Salix div. spec Typha minima, Flooding vegetation Alnus & Salix woods Dry woods Pinus div. spec. 16

17 17

18 Pioneer vegetation a) species form the higher altitude debris fields and alpine meadows b) species which grow only in alpine riversides key species 18

19 Pioneer vegetation perennial Key species Chondrilla chondrilloides 19

20 Pioneer vegetation - perennial Key species Epilobium dodanei 20

21 Pioneer vegetation - shrubby (Salicetum elaeagnii) - Key species Salix elaeagnos 21

22 Pioneer vegetation - shrubby - Key species Myricaria germanica 22

23 Pioneer vegetation perennial - Key species Typha minima in old channels 23

24 Bare & Pioneer vegetation Key species: Epilobium div. spec., Myricaria germanica Salix div. spec Typha minima, Flooding vegetation Alnus & Salix woods Dry woods Pinus div. spec. 24

25 Flooding vegetation Alnus incana & Phragmites communis 25

26 Dry woods- Pinus sylvestris 26

27 3.5 Biology of key species Example: Typha minima Hoppe High seed production but no permanent seed bank wind & water dispersal Fast germination in newly created habitats Long root system High capability of regeneration Biennial or woody (never annual) Stress- tolerator in the sense of GRIME 1979 Meta-population concept 27

28 4. Human impact on alpine rivers 1500 changes catchments' area nutrient input loss biogeogr. barriers 1900 river- regulation 1950 power plant dams.. 28

29 Decline Myricaria germanica in the N-Alps in the last 100 years due to civil engineering measures 29

30 Expansion of ruderal and invasive alien species - neobiota 30

31 Summary 1500 changes in the catchments area.. nutrient input loss biogeogr. barriers 1900 river- regulation 1950 power plant dams.. Since 2000 river restoration and revitalization Background two European Directives a) European Union Water Frame Directive b) European Union Habitat Directive NATURA

32 5. Tagliamento - the last large natural river in the European Alps Tagliamento 32

33 33

34 5. 1 Morphology and vegetation 34

35 Upper course - transect 1 & 2 35

36 36

37 Middle course - transects 3 & 4 37

38 38

39 Middle course transects 5 & 6 39

40 40

41 Lower course - transects 7 & 8 41

42 42

43 43

44 44

45 5.2 Plant diversity (species number) in the longitude Total species number in the investigation areas 1 Mauria Forni di Sotto Amaro 304 Standorte 4 Cornino 5 Spilimbergo Casarsa Bolzano Latisana Artenzahl 45

46 5.3 Key species (species number) in the longitude pioneer- & floodplain vegetation Anzahl Zielarten in den Untersuchungsgebieten Mauria Pionierstandort Auwald Forno di Soto Amaro Cornino Spilinbergo Casarsa Bolzano Latisana

47 5.4 EU Directive Habitats & importance nature conservation a) last (semi) natural river in the Alps with all types of riparian habitats b) largest natural corridor in Europe connecting the continental with the Mediterranean biome Example coherence of the key species Calamagrostis pseudophragmites 47

48 3220 Alpine rivers and the herbaceous vegetation along their banks 48

49 3230 Alpine rivers with Myricaria germanica (Salici-Myricariertum) 49

50 3240 Alpine rivers with Salix eleagnos (Salicetum eleagni) 50

51 7230 Alkaline Fens 7240* Alpine pioneer formations 51

52 91E0* Alluvial Forests (Alnion incanae, Salicion albae) 52

53 91F0 Riparian mixed forests along great rivers (Ulmenion minoris) 53

54 3270 Rivers with muddy banks (Chenodion rubri, Bidention) 54

55 EU Directive Habitats und connectivity 55

56 56

57 6. Risks for the Tagliamento Old technical plans of the Region Friaul Venetien for highwater prevention (Hochwasserschutz) of Latisana Latente Gefährdungen Technical constructions along the river and their z. B. Fella Deforestation and agricultural landuse of the floodplain area Biological Invasions 57

58 Geplante Hochwasserrückhaltebecken zwischen Pinzano und Dignano 58

59 Exotic species (species number) in the longitude pioneer- & floodplain vegetation Artenzahl Neophyten in den Untersuchungsgebieten (UG) auf Pionier- und Auwaldstandorten Mauria Pionierstandort Auwald Forni d.s. Armaro Cornino Spilenbergo Carsarsa Bolzano Latisana

60 60

61 7 Challenges and chances for the future 1 International Protection of the whole Tagliamento river corridor as a UNESCO World Heritage Site 2 European Union Support the local authorities (Friaul and Ventia) along the Tagliamento with special programs of the EU to protect biodiversity e. g. LIFE + Development of the area as a model region for sustainable river management within the EU Water Frame Directive 61

62 Thank you! 62