Wensum Macrophyte Survey Revisited
About 25 years ago Benoit Demars (A PhD Student from Leicester University) surveyed the River Wensum for macrophytes and phosphorus before (1999) and after (2000-2001) P-stripping at East Dereham and Fakenham WWTP. Along the whole water course, in tributaries, upstream-downstream effluents and upstream-downstream weirs.
This was part of his PhD supervised by Prof David Harper, well know to many followers of WCP.
The now Dr Benoit Demars offered to come back and re-survey the macrophytes of the River Wensum this summer at exactly the same locations to quantify the long term changes in vegetation cover and species composition.
He is now a researcher in Norway and has a potential MSc student from the Norwegian University of Life Sciences who could assist with this and help write up the results.
Benoit has undertaken this work for free and only asked to cover his expenses, around £1000, which WCP has secured from a grant from the Broads Catchment Partnership.
He has published a number of articles including the River Wensum in botany (water starworts in Norfolk rivers; 2000), aquatic plant communities (2005, 2014) and phosphorus in water and sediment (2002, 2005a,b). See http://benoit-demars.squarespace.com/s/Hydrobiologia_1998-oixn.pdf
You can access all these publications on his personal website
http://benoit-demars.squarespace.com/
For 2024 Benoit surveyed 16 defined locations as below in week commencing 22nd July.
Its too early to draw any conclusion as yet, but in a general discussion with Benoit, he felt the river had changed significantly in 24 years, much wider and encroached. His initial analysis was there is a 50% reduction in plant species diversity. But this will be defined further by analysing the data.
Clearly this cam only add to the evolving data sets we will have from the planned studies understanding in 2024.
Natural England are currently engaging consultants, to undertake the complete Wensum SSSI assessment.
The EA are currently undertaken 21 fish surveys across the complete Wensum.
So at the end of 2024, we should have a sound evidence set of how the status of river ecology, something missing for many years.
Below is an image of Dr Benoit Demars in the river at Doughton upstream of Fakenham.
