The workshop marked the beginning the Society’s Survey of Bryophytes of Arable Land (SBAL). On the first day there were lectures and practical sessions; the SBAL recording pack was handed out. On the second day we tried out the methodology in the field. It was a pleasure to welcome three visitors from overseas, Irene Bisang and Niklas Lönnell from Sweden, and Herman Stieperaere from Belgium.
Saturday 16 September
Ron Porley set out the conservation background to SBAL. Cereal field margins are a priority for the Biodiversity Action Plan. In spite of this, little is known about how arable bryophytes have responded to past changes in farming practice. We need more information on the effects of organic farming, on the value of regularly leaving winter stubble, and on the types of flora that can be expected under crops other than cereals.
Irene Bisang introduced us to the biology of arable bryophyte diaspores. There are often large discrepancies between the diaspore bank and emerged plants on the surface. Pleurocarpous mosses are normally absent from the diaspore bank. Bryophyte spores and vegetative propagules are often long-lived. They can be incorporated into deeper soil layers, for example by earthworms. There is little inherent dormancy or seasonal variation (Sphaerocarpos texanus is an exception). Spores of Anthocerotae persist in the soil over long periods, mature plants being apparent only in years that have a favourable crop.
Mark Hill outlined the survey methodology and possible approaches to analysis. The SBAL methodology recognizes three types of field: random (located in a randomly selected tetrad), ordinary and special. Analysis will seek to identify patterns of response to differing soils and climate, as well as the effects of farm management.
Chris Preston described how to use the card. The card is complicated, but rapidly becomes easier to fill in with practice. SBAL contributors are urged to persevere and not to panic. In particular, cover values and species frequencies estimated by eye do not have to be very accurate.
Finally, David Holyoak told us about Bryum in arable fields. He handed out draft keys to European species of Bryum. Several microspecies allied to Bryum bicolor do not appear to be distinct, being connected by obviously intermediate plants. British bryologists should keep an eye out for B. demaretianum and B. valparaisense.
Sunday 17 September
In calm dry weather the party of 28 bryologists made its way to an arable field at Ford, about 3 km from Preston Montford. First, we recorded at a station in the centre of the field. Then the party divided to record the four corners. Although the field was quite rich in bryophytes, with a total of 22 species, the species were typical for wheat stubble on slightly acid loam, pH 6.6. Bryum bicolor was abundant, and B. rubens, B. violaceum, Dicranella staphylina, Ditrichum cylindricum and Tortula acaulon were frequent. There were small quantities of Ephemerum serratum var. minutissimum, Pleuridium acuminatum, Riccia glauca and R. sorocarpa.
The next site was a field, pH 7.4, near Atcham on the River Severn, in one of the 100 random tetrads to be visited by SBAL. Although randomly chosen, it proved to be remarkably interesting. Tortula truncata was abundant. Barbula unguiculata, Bryum bicolor, B. violaceum, Pohlia melanodon and Tortula acaulon were frequent. Hennediella stanfordensis was present. Mark Lawley found Pohlia lescuriana (with round tubers) and Chris Preston found P. melanodon (with moniliform tubers). The best find was Didymodon tomaculosus*, new to Shropshire, detected first by David Holyoak and subsequently by Jonathan Sleath. A nearby stubblefield, pH 6.9, bordering the Severn, was examined by Sam Bosanquet, who had noticed H. stanfordensis there. Many of the same species occurred, including D. tomaculosus, found by Ron Porley. Bryum gemmiferum, Lunularia cruciata and Marchantia polymorpha were added to the list for the day. Sam again found Pleuridium acuminatum. We had lunch in the open air, listening to the swirling waters of the Severn as they flowed under the fine old bridge.
Lower Betton Farm (SJ50J)
In the afternoon, the party visited a second randomly selected stubblefield, pH 6.9, on the other side of the same tetrad. No new species were added, but we recorded 21 species, including Bryum gemmiferum, Ephemerum serratum var. minutissimum and Riccia glauca. Pohlia melanodon from this field also had tubers. The weather remained excellent, and as the sun was setting the remnants of the party took tea with Will Prestwood, an ecologist who happens to live at Lower Betton Farm.
Taken together, the two random fields and that at Ford averaged 22.7 species per field. The average for the mid-field positions was 16.7 and that for the corners or ends was 15.0. Recording of edge positions resembled that on a normal field visit, the high whole-field totals being the consequence of intensive recording by many bryologists. However, Sam Bosanquet’s field by the River Severn was not searched more intensively than on a normal field visit. It produced 25 species. Proximity to the river clearly enhanced the species list.
The main purpose of the workshop was to familiarize the team with field procedures for SBAL. At the end of the second day, most of the party had gained confidence, not least because they had been asked to fill in one of the recording sheets. It was a pleasure to see such real enthusiasm for the project. SBAL has got off to an auspicious and enjoyable start.