1. Techniques for restoring biodiversity: What works
Techniques for restoring biodiversity: What works? What are the priorities?
Not reinventing the wheel – building on the existing evidence base.
Judy England, Environment Agency
Martin Janes, River Restoration Centre
Jenny Wheeldon, Natural England

2. REstoring rivers FOR effective catchment Management
Although initially aimed at delivering the WFD the approach and conclusions are relevant to
Floods Directive, restoration measures through improved retention, storage and discharge/ Natural Flood Management
EU Biodiversity Strategy whose targets include restoring at least 15% of degraded ecosystems by 2020, by integrating green infrastructure into land-use planning. Restoration measures can play a significant role in the achievement of biodiversity protection objectives for specific habitats and species (according to the Birds and Habitats Directives).

3. REFORM hydromorphology framework
Hydromorphological assessment should consider physical processes and appropriate temporal and spatial aspects beyond river restoration project boundaries and project life span..
Role of vegetation & floodplain ecosystems
Findings suggest that direct measurements of hydromorphological processes and riparian vegetation are likely to be better in assessing hydromorphological degradation than in-stream biota.
Vegetation and plants can play a cost-effective and significant role as physical ecosystem engineers for river restoration.

4. Improved coupling of hydromorphology to biotic response
Hydromorphological impacts can take years to fully manifest themselves.
Fish is the most sensitive biological quality element (BQE) with regard to hydromorphology.
Macrophytes can be used for assessing hydromorphological degradation in lowland rivers,
Current WFD sampling methods are not appropriate. There is a need to develop new biota sampling methods sensitive to HYMO impacts – include riparian habitats.

5. Restoration measure at a project scale
Projects should have well-defined quantitative success criteria.
Hydromorphological restoration has an overall positive effect on biota, but effects are highly variable and even negative. It is thus essential to monitor and adjust restoration projects.
River restoration benefits not only aquatic biota. Terrestrial and semi-aquatic species benefit most (e.g. floodplain vegetation, ground beetles).
No single “best measure” Widening of water courses to restore a more natural planform. Instream measures have the highest effect on fish and macroinvertebrates. Overall, measures should be selected taking consideration of the targeted organism group.

6. Restoration measure at a project scale
It is important to select measures that restore specific limiting habitats at relevant scales.
Restoration results in a higher number of individuals (abundance) but few new species (richness).
Consider re-colonization potential.
Restoration had positive effects even in small restoration projects. However, other studies indicate that exceptionally large projects have higher effects.

7. Key principles for river restoration
Improve overall ecosystem integrity and biodiversity, rather than focusing on the status of single species, by using process- based techniques such as floodplain reconnection.
Understand the connections between natural processes upstream and downstream: work beyond the scale of individual reaches to consider riparian areas, floodplains and the wider catchment.
Target measures at the root causes of degradation – not the symptoms – and at the scale at which the pressures exist.
Use minimal intervention wherever possible to reinstate natural processes so that rivers can recover by themselves.
Addy et al River Restoration and Biodiversity

8. REFORM fact sheets

9. Restoration measures to improve river habitats during low flows
Slow flow refugia
No refugia
Why we need restoration
Particular concern at extremes of flows
Ecological resistance & resilience
More natural channels have refugia at high & low flows
Natural channels have increased ecological resilience & resistance
Supports the need to link habitat restoration with flow restoration
Flowing refugia
No refugia

10. Environment Agency 2016

11. Environment Agency 2016 Explain table
Highlights most of the published evidence focusses on active and passible single thread.
Tells us some things we know – adding gravel to passive single-thread rivers is was considered inappropriate and the conclusion is supported by evidence with a high confidence. This measure is not sustainable where excess fine sediment is an issue and is not managed.
Highlighted research priorities – considered low possibly of success and there was little evidence.
This research into selected case studies to improve our knowledge.
Environment Agency 2016

12. Mainstone draft (2017) : Review of ecological benefits of river restoration measures
Impossible to made general statements about the ecological benefits of river restoration as schemes vary so widely in terms of the characteristics of the rivers involved. A conflicting and confusing evidence base is inevitable.
Most uncertainty of restoration benefits exists around interventionist measures
1) Some of the most well-thought our practical schemes may yield no evidence because monitoring was either not considered or was too coarse to be of value. Schemes with poor strategic planning may generate monitoring data capable of analysis, but are unlikely to show significant ecological benefits.

13. Natural flood management- evidence base
Headwater drainage
Leaky barriers
Catchment woodland
Cross-slope woodland
Runoff pathways
Floodplain restoration
Riparian woodland
Here are the 14 interventions we can make
Offline storage
Soil and land management
River restoration
Salt marsh, mudflats and managed realignment
Floodplain woodland
Salt marsh, mudflats
Sand dunes
Beach management

15. Addy et al. 2016 River Restoration and Biodiversity

16. The benefits of wood
Collins et al Geomorphology

17. Some thoughts on gaps: Higher energy systems
Assisted natural recovery/reduced maintenance
Think wider – riparian, floodplain & catchment:
Woodland creation/regeneration
Natural flood management
Catchment sensitive farming
What can we learn from the recent floods (& future droughts)?
What is popular?
England CP’s work, faggot bundles, wood in rivers, weir removal/notching/etc, NFM
Scotland Fisheries trusts and SEPA – morphology based restoring space and processes and green bank protection
Wales – better ‘green’ bank protection & NFM related techniques
NI – weir removal, green bank protection, mitigation for flood risk works
Ireland… - enhancement based on reduced changed maintenance.

18. Do we need two lists? Complex/large scale: Simpler/smaller scale:
where there is a need for good quality monitoring and scientific understanding to generate better quality evidence to help design and implementation,
Simpler/smaller scale:
where there is a need for greater assessment of the large numbers of simple projects implementing the same ‘common’ techniques – i.e. there is a large sample size already (multiple BACI).