Cop Mere SSSI - WOODLAND (002)
Staff member responsible: PAUL CANDLIN
Unit Id: 1014815
Unit area (ha): 15.6934
Unit Status: Live Gridref: SJ 799 299
Main habitat: BROADLEAVED, MIXED AND YEW WOODLAND - Lowland
Condition (click for history): Unfavourable - Recovering Assessed by: HOLLAND, (TOM)
Last assessed: 19/03/2018 Last field visit: 12/09/2017
ISA Survey: View Surveys
Date of site check: 12/09/2017 Last CSM assessment: 19/03/2018
Condition assessment comment:

Notified feature assessment –

  • I’ve measured the area of poplar to cover about 1.5 of the woodland’s 13 hectares – i.e. covering 11% of the wet woodland area. The SSSI condition target is actually expressed as percentage of the canopy cover, rather than woodland area. So in unit 2, where canopy cover averages about 50% (calculated from notes taken at my ten stops), I think the cover of poplar might be more like 15-20% of canopy (i.e. poplar cover averaged 8% of the 50% canopy). Of other non-natives there are one or two conifers and sycamore in the canopy and one or two areas of currant and rhododendron in the understorey. The latter occur around SJ79754 29866. There appears to have been a dramatic decline in Himalayan balsam between 2015 and 2017 (assuming I identified it correctly in 2015 or didn’t miss it this year). Why? Has the land-owner done some control or was the woodland flooded last August and September (when it was spreading seed) or this spring (when it was germinating)?
  • In 2015 I noted the frequency and high cover of nutrient-loving species (eutraphents) like Urtica, Phalaris, Epilobium and Glyceria in the ground flora. This year I tried to put some numbers on this observation. Nettles were present in 80% of stops with an average cover of 35%. Reed canary-grass was present in 50% of stops with an average cover of 5%. Reed-sweet-grass was present in 20% of quadrats with an average cover of 10%. Therefore I reckon the combined cover of nutrient-loving species (eutraphents) to average about 50%, which seems quite high to me. Bramble, which might respond positively to both nutrients and drying conditions, also had a high cover and frequency, occurring in 80% of stops and averaging 10-15% cover.
  • In 2015, I wondered if the River Sow could be the source of the eutrophication (if surface-water from the Sow might flood unit 2’s wet woodland during high flows).
  • EA’s website http://environment.data.gov.uk/water-quality/view/sampling-point/ gives data from a regular sampling point at the Cop Mere inlet at SJ79180 29750. At this point, it has measured average soluble phosphorus at 78ug/l in 2015; 89ug/l in 2014; and 80ug/l in 2013; and average Total Nitrogen at 8.43mg/l in 2015; 6.78mg/l in 2014; and 6.46mg/l in 2013. Other sampling points downstream of Cop Mere tell a similar story – low soluble P and high nitrate.
  • The TN is comprised mainly (95-100%) of nitrate as N, sourced presumably from agriculture in a catchment dominated by improved grassland and arable/horticulture (according to Atkin’s Establishing Phosphorus and Nitrogen Budgets for the Shropshire and Staffordshire SSSI Meres, 2010).
  • Meade et al (Nitrogen and phosphorus thresholds in water feeding terrestrialised wetlands, 2006) suggests a threshold of 30ug/l of soluble phosphorus to maintain eutrophic wetlands, fed by surface waters from rivers. The UKTAG (Technical report on groundwater dependent terrestrial ecosystem thresholds, 2014) suggests a threshold of 5mg/L of nitrate Nitrogen to maintain groundwater-fed eutrophic woodlands. I can’t see why it makes a difference whether the water comes from ground-water or surface-water? Common Standard Monitoring for freshwater suggests a target of 1.5mg/l of TN.
  • So EA’s data seems to suggests water quality for both soluble P and nitrate is not good enough to maintain wet woodland in good condition?
  • Therefore the high cover and frequency of nutrient-loving plants in the vegetation might be explained as eutrophication - caused perhaps by nitrate sourced from agriculture brought in by Sow’s floodwaters (and phosphate sourced from ??).
  • Alternatively (or additionally), the eutraphents might be responding to nutrients released from what seem like relatively dry peaty soils. As noted in 2015, the woodland floor seemed very dry (and easy to walk upon), compared to other wet woodlands I’ve visited (even when the time of year is taken into account). I measured the depth of peat, using a stick, as I walked around and it was generally over 1m, except near to the edges.
  • A drain-blocking exercise is likely to restore a more natural hydrological regime and raise water levels in the peaty soil.
  • Although the present frequency and covers of eutraphents seem high, they are consistent with the upper end of the range of values given in the NVC tables for W5, W6 and W7. Even though, this seems likely to indicate eutrophication, from past advice received from national specialist, I think this is enough for the ground flora to be considered in favourable condition. Lowland fen targets are less tolerant. Such covers and frequencies when assessed against lowland fen targets would make the.

Conclusion

  • As things stand (i.e. with the apparent disappearance of Himalayan balsam), it would seem possible to move the unit from unfavourable recovering to favourable with a bit of effort. – i.e. greatly reducing poplar cover and blocking ditches. However, this ignores the eutrophication issue.
Number of adverse condition reasons: 0
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