Vegetation (Floating River Vegetation) - Office of Public Works

(Ranunculus) species namely R.penicillatus ssp. Pseudofluitans, R.fluitans. If the above diversity is
the typical trend across Europe, it explains the reasoning for emphasizing water crowfoot species
when classifying habitat EU 2360, watercourses of plain to montane levels, with submerged or
floating vegetation. The presence of R.penicillatus ssp. Pseudofluitans in five of the six groupings
suggests that it is a species that has either successfully adapted to a number of different riverine
habitats or all watercourses have been subjected to substantially the same modification regime.
To highlight and prevent the decline in floating river vegetation across the United Kingdom a series
of Local Biodiversity Area Plans have been compiled identifying threats to aquatic vegetation and
action to be taken to reduce loss. Threats to floating river vegetation include:
•Modification of watercourse depth and flow.
•Over abstraction of groundwater
•Water quality, by agricultural run-off, and cattle loafing and industrial pollution
•Increase in suspended solids within the water column
•Engineering and construction works
•Physical damage to plants by human activity
•Excessive shading by overgrown hedgerows especially on smaller watercourses.
Modification of watercourses by changing width, depth and flow of rivers has contributed to
an increase in siltation of some rivers during summer months as water levels drop.
Over abstraction of groundwater can result in lower water levels and drier watercourses,
increased risk of pollution and higher rates of siltation.
Reduction in water quality and the nutrient loading of watercourses can favour the growth of
other aquatic vegetation. It has been reported that R.fluitans can tolerate slight pollution but is
intolerant of water turbidity (Northern Ireland Species Action Plan).
Engineering work including the building of bridges and reservoirs can alter the flow of
watercourses. It has suggested that the use of concrete and cement components in aquatic
environments impacts on the physical and chemical characteristics of watercourses (Hatton-Ellis &
Grieve, 2003).
Human leisure activities can cause shearing and hence damage to floating river vegetation
(Cheshire-biodiversity, Northern Ireland Species Action Plan).
Excess shading from hedgerows, riparian woodland or managed woodland has also been
identified as a threat to floating river vegetation by reducing the availability of sunlight (O' Grady,
2006).
Management and conservation strategies for the preservation of existing floating river vegetation
habitats and habitat enhancement include:
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