2023 County Report for Middlesex

Dr Mark A. Spencer

2023 has been very much a ‘desk-top’ year! The majority of my BSBI and London Natural History Society (as the vascular plant recorder for the LNHS – covering the Greater London Authority (GLA) area and nearby parts of adjoining administrative counties) time has been devoted to producing vascular plant Red and Axiophyte lists for Greater London and Middlesex.  The Red-list will form the basis for a Rare Plant Register that will, initially, cover a planned revision of the GLA Priority Species list. The draft results of the Red-list are disturbing, of 964 assessed taxa (native & archaeophyte) 169 species are regionally extinct, this is likely to be a conservative estimate as there are many other species that have not been confirmed for a long time. A further 17 species such as Cornflower (Centaurea cyanus) have extant neophyte and ephemeral populations but are classed as regionally extinct in the wild. Another 156 species that have been assessed (either GB or England) nationally as Near Threatened, Vulnerable, Endangered or Critically Endangered are, usually, under greater risker of extinction within the GLA area or Middlesex. Finally, a large proportion of the species listed as Least Concern at a national level (either GB or England) are facing some level of extinction risk within the region.  The above work, and the associated work on an axiophyte list could not have been done without the assistance from our local records centre, Greenspace Information for Greater London (GiGL), Paul Losse (Salix Ecology) and Julija Fediajevaite. We are planning a consultation exercise before the final documents are made available online via the BSBI, LNHS, GiGL and the GLA.

I led four joint BSBI/LNHS field trips in 2023: Victoria Park & Hackney Wick (20th May 2023); Rammey Marsh (17th June 2023); Monken Hadley Common (22nd July 2023) and Syon Park (19th August 2023). These walks provided some interesting records as well as helped forge greater connection between the LNHS and BSBI. After completing the consultation on the Red and Axiophyte lists, I will be compiling and submitting data to the BSBI and the LNHS (pending ratification of data sharing agreements between these orgs and our local records centre, GiGL).

I was glad to be able to confirm the healthy status of two Middlesex rarities, Autumn Squill (Scilla autumnalis) and Harebell (Campanula rotundifolia) at Hampton Court; the former is now only found at Hampton Court while the latter has reported from fewer than 10 locations, several of which it appears to died out from and the others are probably dubious or planted records. As it stands, it is probable that Hampton Court and the nearly Bushy Park are the only sites where this species has a future. John Salisbury was able to confirm that the important population of Tower Mustard (Turritis glabra) at Stain Hill Reservoir (not a public site) was doing well and he recorded several hundred plants. Sadly, during the joint LNHS/BSBI trip to Syon Park we were unable to locate Greater Water-parsnip (Sium latifolium) which I fear is now extinct. On the joint LNHS/BSBI trip to Monken Hadley, I pleased to confirm the presence of Heath Grass (Danthonia decumbens) a species that faces the probability of extinction in the county within the next few decades. Astrid Biddle was able to confirm Greater Bitter-cress (Cardamine amara) in the far north-west of Middlesex, right on the border with Hertfordshire, this is yet another species that is not nationally threatened but is in deep trouble in the London area.  Mario Maculan found corky-fruited water-dropwort (Oenanthe pimpinelloides) near the Thames, this was only the second time that this nationally localized but apparently increasing species has been seen in the county. David Solomon found the non-native Western Sword Fern (Polystichum munitum) in the grounds of Alexandra Palace, a county first. I’m rather fond of pondweeds and 2023 was a very good year for Potamogeton spp. in Middlesex. On the joint LNHS/BSBI walk in the Victoria Park area Hairlike Pondweed (P. trichoides) was found for the first time in the area; up until a few years ago this species was considered to be extinct in the county, it has now been found in several areas indicating its either been overlooked or is recovering. On the same trip, Shining Pondweed (P. lucens) was re-found at its last known site in Middlesex, the colony had not been seen for several years and I feared it had succumbed to the Canal and River’s Trust’s increasingly exuberant management of our waterways. Finally on a hot summers day in Kings Cross Trevor Dines and I found Flat-stalked Pondweed (P. friesii) in several locations along a stretch of the Regent’s Canal that I know very well; this species was last seen in the county in 1949 – I was quite chuffed.