Maudlin Pond 2020

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Picture of Lycopus europaeus (Gypsywort)
Lycopus europaeus (Gypsywort)

Source: Matcham, Howard. “Maudlin Pond 2020.” Sussex Botanical Recording Society Newsletter, no. 91 (November 2020).

It is two years this autumn since Maudlin Pond was excavated to a depth of c.15ft and the excavated soil used to berm the surrounds. There have been losses, for example Coot and Moorhen have gone as no nesting sites remain; Little Egret spent a great deal of last summer and early autumn on the mud exposed by the dry summer, occasionally with a pair of Grey Heron.

Botanically the pond was a floristic disaster with a very small amount of the formerly abundant Ranunculus aquatilis (Common Water-crowfoot) along the western edge, and the berms were colonised by Conyza sumatrensis (Guernsey Fleabane), docks and precious little else.

Welcome to 2020: spring and the entire surface of the pond was covered with R. aquatilis a beautiful sight indeed, Water Starwort (Callitriche sp.) reached for the sky and the dreaded Lemna minuta (Least Duckweed) was completely absent and has remained so; the berms were a floristic delight with complete coverings of competing Lythrum salicaria (Purple-loosestrife); Lycopus europaeus (Gypsywort) and Mentha aquatica (Water Mint) all in vast numbers with C. sumatrensis forcing its way in between. Other species flowered prolifically. So all is not lost.

Currently the surface is clear over most of the pond but there is, for the very first time, a cyanobacteria bloom of the toxic alga Anabaena circinalis.

Picture of the green alga Anabaena circinalis, which looks like a string of beads
Anabaena circinalis Photo: Chris Carter

Rorippa palustris (Marsh Yellow-cress) which colonised the berms in 2019 was seen for the first occasion on the mud of the floor of the pond in the autumn of 2017, where it occurred with the terrestrial form of Ranunculus aquatilis which has much larger flowers than the normal aquatic form; this year Rorippa palustris has become extensive on the northern berm. It was a new tetrad record in 2017, belatedly sent in by me last year.

The liverwort Riccia cavernosa (Cavernous Crystalwort), discovered by me in October 2003, covered the mud of the entire dried out pond with thousands of individual thalli. At the time this was the most prolific site for this species in southern England and probably throughout the British Isles; it is unlikely that it will be seen in such numbers again, if at all.

Surrounding willow trees were all grubbed out, which was unfortunate as they were clothed with bryophytes and one had a resupinate fungus (Peniophora rufomarginata) that was believed to be in its only extant site in VC13 West Sussex. It has not yet been seen in VC14 East Sussex.

It’s worth pointing out that the pond does not have ingress or egress either by ditch or by the usual Victorian clay drainage pipes and it fills by rainwater and fluctuating water table. Yes, there are irreplaceable losses of some bryophytes, fungi, and of the algal flora but as in all things natural it is evolving, and newly recorded species undoubtedly will be found. In this awful time I found looking at the vibrant colours of the three species, Purpleloosestrife, Gypsywort and Water Mint therapeutic indeed.