Last year, five of us conducted three quadrat surveys of the meadow areas to the east of the railway viaduct in Perivale Park (below, red arrow). This is a beautiful grass meadow and part the Greenford-Gurnell Greenway project, whereby the south meadow has been converted to new wetlands, with the little stream feeding these wetlands running alongside the north meadow. This meadow and the adjacent new wetland ponds featured in a local BBC news item recently.
The survey was led by Richard Bullock, who is expert in biodiversity. He has sent me his analysis of these surveys:
Visit to Perivale North meadow on 5th May 2019. The two May quadrats have been named “Quadrat 3” and “Quadrat 4”. This info is adjacent to the two quadrats taken in August.
It looks like the Quadrats average c. 20+ species per 2×2 metre quadrat. John Rodwell (1992) suggests that mesotrophic grassland is species-rich if 23 or more species occur in a 2x2m quadrat. Therefore, these meadows aren’t far off this value. Natural England’s evaluation suggests 15+ species per 1×1 metre quadrat to receive higher level payments. Taking a quick look at the Magnificent Meadows website, I think this grassland easily makes “Semi-improved Grassland” criteria, and with a little encouragement (e.g. Yellow Rattle) and perhaps some degree of hay cutting management, the meadow may well be very suitable for restoration to species-rich grassland. The Clattinger meadow mix‡ could be interesting if it contains any Green-winged Orchid seed. I’m of the impression that the Perivale ‘North Meadow’ field ranges from circum neutral pH / base-rich (with Lady’s Bedstraw in the sward) through to the acidic side of neutral on the west side of the field where the Sheep’s Sorrel and Bird’s-foot occur. The upper section of the field on the shedding slope is probably reasonably well drained. The bottom of the slope clearly is influenced by damper conditions.
One other factor to consider is that we have sampled beginning (start May) and end (end August) of the grassland sampling season. Ideally, it is recommended quadrats are taken in June and July to get the best idea of status for assessment. Sampling in c. mid-June might show the grassland in its true colours re. species-richness. At this time of year, the diversity of grass species will be much more apparent within each quadrat.
One or two species, although not rare or scarce nationally, may be much more restricted in range within Greater London or LB Ealing; for example, a species such as Bird’s-foot Ornithopus perpusillus.
I have included the lists of species found in each of the quadrat surveys, illustrating the wonderful diversity of this meadow! Click on the image to expand it into readability.
‡Ealing parks will shortly be “disturbing” the surface of the meadow and seeding it with a Clattinger mix which includes 20% yellow rattle.