Biodiversity surveying

We are building up a record of species found in the water meadows through systematic survey. Iain Carruthers-Jones leads this work and would be pleased to welcome new volunteers to the biodiversity surveyin team. Contact Iain if you are interested.

Photo: Greater Spotted Woodpecker on the Crankles, by Jillian Macready

Species observed in the water meadows this year:

Look out for our BioBlitz in summer 2022, when for a 24h period, there will be a race against the clock to find as many species as possible in the Crankles and No Mans Meadow. Will we get a thousand for the 1000 years of the Abbey of St Edmund??

BWMG biodiversity survey 2020

This is a preliminary report of the 2020 biodiversity survey in the historic Bury St Edmunds Water Meadows. The survey took place in late summer 2020 in the 5 hectares of green space that comprise the Crankles, No Mans Meadow and Ram Meadow. Within this area are two chalk streams, the Lark and the Linnet.

The team of observers included Anna Saltmarsh (AS). Libby Ranzetta, Sue Russell, Jillian Macready and Iain Carruthers-Jones (ICJ).

37 types of birds were recorded. The largest bird sighted was a raptor. A Buteo buteo (buzzard) was seen several times and in different locations. It would seem likely that this is a single bird; we had no sighting of a pair of birds and no active nest was seen.
However, an old nest has been seen on adjacent land owned by the Gulls.

In July, there was a sighting on Ram Meadow of a hunting Kestrel. It was close to a strike on a pigeon when it pulled away. The pigeon survived to breathe another day. Clearly others had not been so fortunate because there was a large spread of feathers on the ground nearby.
A pair of egrets were sighted in Ram Meadow as well. While this was the only sighting of a pair there were several sightings in the Crankles and No Mans Meadow of solitary birds. A heron has been seen a number of times in various locations along the Lark and the Linnet.

A pair of swans fledged a single cygnet. Their range stretched from the Lark bridge that crosses the Crankles as far downstream as the Eastgate weir. They were last seen as a family in late September. One parent and the cygnet were seen for another week or two. Finally the cygnet was left alone. It has not been seen since mid-October.

There have been sightings of pheasants and partridges. One partridge mother raised a brood of five cheepers very conscientiously for several weeks and could be seen at different locations in the Crankles and No Mans Meadow.

There were many sightings of pigeons, crows and rooks. One morning in May ICJ witnessed an unusual sight. In No Mans Meadow a couple of sheep were surrounded by rooks. At first it looked like they might be attacking the lambs that were with the sheep. However, on closer inspection, it became obvious that this was not an attack but a collaboration. The rook on the sheep’s back was pulling out wool from the fleece and passing it to rooks on the ground. They promptly flew off with the wool, presumably to create a warm and comfortable nest for their fledglings. The host sheep stood still, and presumably acquiescent, for at least five minutes.

There were frequent sightings of some smaller birds. At least one kingfisher has been flying along the Lark from the Abbot’s Bridge to No Mans Meadow. Small flocks of blue tits and long tailed tits have been seen frequently as well. Chaffinch, greenfinch, brambling, goldfinch and linnet have been seen from time to time. There have probably been more than we recorded. Robins and blackbirds have been seen frequently. Other species also sighted include coal tits (frequent), great tits (frequent), wren (frequent but very localised), nuthatch, willow warbler, and swifts.

There have been sightings of magpies but it is difficult to gauge whether they are numerous.

Water based birds have been sighted frequently. Moorhens and, especially, mallards frequent the stretch of the Lark from the North Crankles to the Eastgate weir. It is intriguing that the male birds outnumber the females.

A single grey wagtail was spotted in late July.

Both green woodpeckers and greater spotted woodpeckers have been seen. Various types of gull have overflown but there has been no ground based activity.

The biggest and most numerous category was plants. We recorded 108 different plants. Excluded from this count were plants which were known to have been seeded or planted (e.g. snowdrops or wildflower seed mix) by volunteers in the last couple of years. However, it will be interesting to see which of these thrive.

Of the 108 types recorded there was a huge variety. Some had “old names” like lady’s bedstraw, fat hen, yorkshire fog, sneezewort, old man’s beard and some were old plants which featured in herbals, such as horseradish, marjoram, oregano, angelica, hemp agrimony and St. John’s Wort.

Three plants recorded were a cause for concern. Firstly, himalayan balsam has been seen growing along the river margins. There has been an active programme to remove this vigorously invasive plant.

The second plant is hemlock which has been a prolific grower this year. It is poisonous. It has grown along the river margins at the south end of the Lark in No Mans Meadow and beyond as far as the Lark Path junction with the main road. It has grown to a height of more than eight feet in places; when in full leaf it overshadowed all the other plants along the path.

Hemlock is not a new arrival since it was first recorded in 1548 ( according to the NNSS). It does appear to be spreading possibly due to pollution and eutrophication (high nutrient levels) as well as climate change. While it is not a controlled species in the UK it will be monitored carefully in coming years.

A third plant, giant hogweed, has been seen in the area. While it is not present in our survey area it has been seen on the banks of a ditch leading into the Linnet in Holywater Meadows. This can be described as a problematic, non-native invasive species. Its sap can cause severe photosensitive blistering.

Probably the easiest survey to do involved the trees of the Water Meadows. When you want to count them, like plants, they remain still.! We counted 27 different types. Most numerous were willow (white, black, weeping, grey and crack ) and poplar ( white and black), maple, sycamore, ash and aspen. There were a few horse chestnuts, maple, alder and hawthorn as well as walnut (black and english), elder, scots pine and guelder rose.

Our surveying of butterflies and moths was insufficiently comprehensive and systematic. The coronavirus restrictions blocked our efforts in the first quarter but in the second quarter we saw 14 different types of butterfly. These included large whites, small whites, green veined whites, small blues, peacocks, brimstone, commas, brown argus and gatekeepers. Less common, an eyed hawk moth was seen. It might have been injured because only one “eye” was visible but it must have recovered enough to fly away after a couple of hours. Also observed was an Elephant Hawk Moth caterpillar. What a triumph of camouflage.

Mammals seen have included voles, rats, rabbits, grey squirrels, muntjac deer, roe deer and hedgehogs.
Reptile mats were put out at six sites in the Crankles and No Mans Meadow. They were checked periodically. One was destroyed by grass and nettle cutting. The other five yielded little except for a number of invertebrates.

No reptiles have been seen this year.

Ground nesting bees were seen at several locations in the Crankles and the northern end of No Mans Meadow. It was not possible to be more specific about the types of bee seen because they were extremely irritable and the observers did not have “bee suits”.

It had been intended to survey other species as well. However, it wasn’t possible to do a survey of bats, bees and other insects and fish. It is hoped that they will be included in next year’s survey.

Fungi were not recorded methodically. In recent weeks one giant puffball (Calvatia gigantea) has been spotted. Although not a fungus, a striking slime mould (Tubifera ferruginosa?) was spotted in the North Crankle.

In conclusion, our intention to do an intensive and detailed biodiversity survey was hampered by COVID. Nonetheless we recorded an impressive number of observations, with the most numerous being plants. This year’s survey will serve as a benchmark for next year. If circumstances allow next year we should record more in every category (with the possible exception of trees) since we will have a longer observation and recording window.

A list of records is being stored. All records will be submitted to SBIS (Suffolk Biodiversity Information Service) and will subsequently be available on the National Biodiversity Network (NBN Atlas). Further, we are exploring the use of iRecord as a means of uploading and collating these and future records.

Iain Carruthers-Jones and Anna Saltmarsh
06.11.2020