Hydromorphology & Ecology within river restoration. Name: Dr Judy England Job title: Hydromorphology Research Scientist Date: 9 th September 2014

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1 Hydromorphology & Ecology within river restoration Name: Dr Judy England Job title: Hydromorphology Research Scientist Date: 9 th September 2014

2 Contents Processes affecting aquatic ecology Interactions Understanding habitats How to use your knowledge of habitats in RR What can affect ecological recovery? Where to go for more information

3 What is ecology? Ecology is the study of the relationships between plants and animals and the environment in which they live. Owen, 1980 Why is hydromorphology important? Physical habitat (hydromorphology) is one of the key supporting components of a healthy aquatic ecosystem

4 Ecological response to hydromorphological change

5 Hydromorphology influences ecology Longitudinal processes: Hydrology Fluvial geomorphology Lateral processes: Interactions with riparian zones & floodplains Vertical processes Connectivity with groundwater Internal processes: Predation, competition etc.

6 Mechanisms of ecological change to natural hydrological regime of a river Source: Bunn and Arthington, 2002

7 Influence of hydrology on invertebrates Some species have flow preferences, relating to feeding preferences, physical adaptations, Simulium sp Sialis lutaria Frequency Frequency Spate Fast Moderate Slow Slack Velocity category 0 Spate Fast Moderate Slow Slack Velocity category Black fly larvae, filter feeders. Preferred velocities - a balance between those that bring food particles and being dislodged. Alder fly larvae, burrowing predator. Preferred velocities a balance where prey can be found and being dislodged. Alder fly photo

8 Influence of geomorphology Impacts on substrate size Impacts on substrate patchiness Impacts on substrate movement Impacts on substrate depth % % % Depth cm Depth cm Depth cm After Bretschko Caddis flies 60 Stone flies 60 May flies

Influence of substrate on invertebrates 70 50 Numbers 60 50 40 30 Medium gravel Fine gravel Very fine gravel Very coarse sand Coarse sand Fine sand Medium sand Very fine sand Silt Numbers 40 30 20

9 Influence of substrate on invertebrates Numbers Medium gravel Fine gravel Very fine gravel Very coarse sand Coarse sand Fine sand Medium sand Very fine sand Silt Numbers Medium gravel Fine gravel Very fine gravel Very coarse sand Coarse sand Fine sand Medium sand Very fine sand Silt Median phi Median phi Simulium spp. Sialis lutaria Black fly larvae, filter feeders. Found in larger substrate sizes providing stable substrate. Alder fly larvae, burrowing predator. Found in finer, softer sediment.

10 Hydrological & morphological interaction Simulium sp. 50 Frequency Spate Fast Moderate Slow Slack Velocity category 70 Numbers Medium gravel Fine gravel Very fine gravel Very coarse sand Coarse sand Fine sand Medium sand Very fine sand Silt Median phi

11 Interaction between plants & sediment Source: Haslam 1978

12 Hydrological and morphological interaction influence ecological quality Ecological quality for macro-invertebrates Low High Antecedent low flow conditions

13 Lateral processes Margins & riparian zone habitats refuges food leaf & insects Large wood channel forming Shade temperature climate change adaptation Floodplains

14 Large wood (debris?) Branches, large limbs, root boles or entire trees (>1m in length and 0.1m diameter) that have fallen into rivers are commonly referred to as Large Wood (LW).

15 A major contributor to processes Create lateral scour, helping to form meanders Raises levels upstream, increasing floodplain connectivity Retains fine sediment, reducing entrainment into spawning gravels Changes velocity patterns

16 It helps create diversity Changes in velocity sorts fine and coarse sediment Promotes habitats variation: ideal conditions for spawning salmonid and rheophilic coarse fish (barbel, chub and dace) Cover for fish 147 invertebrates, some rare, strongly associated with woody (Godfrey, 2003)

17 Vertical interactions Water quantity up-welling & down-welling Water quality temperature chemical quality Habitat & refuge flood, droughts & pollutions specialist species salmonid redds

18 Internal processes Physio-chemical processes Nurient cycling Biological interactions: Competition Herbivory Predation Life cycles Source

19 Degraded site Control site The more complex the food-web the more stable it is and the greater the ecological resistance and resilience.

20 Complex interactions

21 Understanding habitats: Source: Newson and Newson 2000

22 Physical Biotopes Marginal dead water Glide Riffle Functional Habitats Tree roots Sand Gravel Cobbles/ pebbles Rocks

23 Physical Biotopes Marginal dead water Run Functional Habitats Sand Submerged Plants Gravel Pebbles Marginal plants

24 Habitats for plants Channel & bank morphology Flow regime semi terrestrial vegetation emergent broad leaf vegetation emergent narrow leaf vegetation Bank full water level floating leaf vegetation Low water level Submerged vegetation tree roots terrestrial vegetation

26 Habitats for invertebrates - physical Riffle Exposed riverine sediments Glide Pool Marginal dead-water Large woody debris Water surface Bank Marginal damp areas Water table Hyporheos Groundwater

30 Habitat considerations for mammals Bats roost, feeding Water voles burrows, feeding, latrines Otters holts, cover,

31 How to use habitat awareness in RR Concentrate on restoring processes Habitats should be appropriate use reference sites Assess biota in relation to the habitat changes Important to monitor changes in relation to the reference/control site

32 Restoring processes Substrate size is important to the distribution of invertebrates How stable will the substrate be? Will the inundation pattern be correct for the desired plants? River Chess, Buckinghamshire

33 Getting the target right Habitat restoration should be appropriate Recreate habitats in comparison with reference conditions. Increase ecological resistance and resilience The distribution of exposed boulders in 1994 and 1995 national RHS survey

34 Assess biota in relation to the habitat changes River Rib, Hertfordshire

35 Control section Degraded section

36 Macro-invertebrate composition of different mesohabitats % composition 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% Emergent Veg Submerged Veg Fast Gravel Slow Gravel Sand Silt Flies Caddisflies Alderflies Beetles Bugs Stoneflies Mayflies Shrimps & Hoglice Hydracarina Leeches Worms Mussels Fuctional Habitat Snails Flatworms Vegetation only Gravel only Fast Gravel only Slow Gravel only Sand only Polycelis felina Lymnaea palustris Lymnaea truncatula Acroloxus lacustris Centroptilum luteolum Baetis vernus Hydrometra stagnorum Velia capri Gerris sp. Haliplus wehnckei Octhebius minimus Helophorus brevipalpis Helophorus minutes Limnephilus lunatus Chelifera sp. Nemurella picteti Dicronota sp. Leuctra fusca Hydroptila sp. Limnophora sp. Athripsodes cinereus Pericoma trivialis Rhycophila dorsalis Tinodes waeneri Hydropsyche sp.

37 Restoration site: Flow Scale: 20 metres Control site: Functional Habitat Emergent Vegetation Submerged Vegetation Fast Gravel Slow Gravel Sand Silt Restored section Control section Before After Before After Functional Habitat: Emergent vegetation Submerged vegetation Fast gravel Slow gravel Sand Silt

38 The theory:..if natural hydrology and morphology are recreated, with careful consideration given to the hydraulic aspects, then there is every possibility that natural ecological recovery will follow. Brookes, A. and Shields, F.D. (1996)

39 What can affect ecological recovery? Catchment context Inappropriate aims Complex processes Timescales Multiple pressures: Water quality Alien species

40 Catchment context Source Impact Source Impact

41 Catchment context Catchment and riparian land use control local habitat conditions Restoration is more likely to be successful, if upstream physical habitat degradation and land use impacts are low Deal with the main pressure other pressures inhibit benefits Local restoration, undertaken without consideration of other pressures acting on river, is often unsuccessful

42 Getting the aims right Understanding the catchment context Interactions with other pressures Identifying project aims Identifying monitoring aims See PRAGMO

43 Practical River Restoration Appraisal Guidance for Monitoring Options (PRAGMO) Available from the RRC website

44 Linking morphology and ecology

45 Complex processes

46 Macrophyte links

47 Invertebrate links

48 Timescales - Lagtime Hydromorphology operates over long timescales River may be moving sediment from last week or last ice age - long history of natural change Long legacy of physical modification Recovery timescales Time lag between physical restoration & ecological response? Initial improvement but not long term? Benefits of restoration may take a long time to be realised Can be difficult to quantify

49 Time scale of recovery Colonisation processes - invertebrates Source of colonists Ability to colonise Succession/biological interactions

51 Interactions with other pressures eg water quality Poor water quality will inhibit biota Amend objectives May not increase richness or diversity but can increase numbers fish food!

52 Brent at Tokyngton Park

53 Water depth <5cm - >1m Water velocity slow - spate No substrate No cover / habitat Water quality

54 Water depth varied Substrate varied Water velocity varied Habitat & refugia

55 Social reaction: I think it s been really good. We used to come to the park before the restoration and after the restoration, and the difference I think, it has made to the neighbourhood has been a big change. I think before people did not use the park as much as they do now. It shows what can be done with time, effort and funding along with the support of the local community and partnerships with other organisations. It gives hope, not only to improve the water quality and local environs of the River Brent but sets a statement of what can be achieved with other polluted or heavily modified rivers within London. Those St Raphael people are a nuisance. They are the scum of the earth. I think the foot bridges are a problem. Mbeke (2008)

56 Non-native species

57 Hydromorphology uncertainty Ecological response to hydromorphological change Quantifying and understanding the processes Effectiveness of measures on hydromorphology and ecological response

58 Where to go for more information: Ecological preferences & ecology Environment Agency UK Technical Advisory Group (TAG) Restoring Europe s Rivers Hydromorphology REstoring rivers FOR effective catchment Management

59 Further reading: General aquatic ecology: Rivers: Holmes & Raven Ecology of freshwaters: Moss Britain s Freshwater Fish: Everard Stream Ecology: Allan & Castillo Restoration Stream and watershed restoration: Roni & Beechie River restoration: Darby & Sear River Conservation and Management: Boon & Raven 59

60 Any questions?

Missouri Streams. Fact Sheet. What factors affect stream habitat? Stream Habitat Affects Aquatic Communities

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