New waxcap fungi translocation method

The construction of the Heysham to M6 link road scheme in Lancaster by Lancashire County Council necessitated impacting on part of an important site for waxcap fungi. Waxcap fungi are a group largely confined to growing in grassland and most frequently in pasture where the turf is kept short by grazing or, in the case of some amenity mown examples, areas such as golf courses and church burial grounds. Some UK waxcap species are regarded as rare and listed as Species of Principal Importance (formerly UK Biodiversity Action Plan (BAP) species).

Pink Waxcap (Hygrocybe calyptriformis)

Pink Waxcap (Hygrocybe calyptriformis)

During the early stages of this project, the pink waxcap (Hygrocybe calyptriformis) was discovered on the site of the proposed link road. At the time, it was listed as a British Red Data List species (Ing, 1992). To mitigate the issue, it was proposed that all waxcap species that were impacted by the development be translocated to an alternative site in the same field complex, which had been acquired by management agreement as a mitigation area. Although the pink waxcap was subsequently removed from the Red List after being found to be more widespread than initially thought, Lancashire County Council continued to honour the translocation attempt. Following a public inquiry in 2007, it had been agreed that all waxcap-rich meadows were biologically important and in decline due to ploughing and other agricultural improvements.

Our Principal Ecologist (until October 2015) Barry Wright was tasked with translocating the waxcaps. Unable to use traditional turf translocation methods due to the specifics of the mitigation area, Barry proposed and oversaw a unique translocation attempt for waxcaps using spores.

Challenges of waxcap fungi translocation

The initial challenge was to find a suitable translocation method. As the mitigation land was organically farmed, the owner was reluctant to allow potentially damaging machinery to access the land. Therefore, traditional waxcap translocation methods involving the translocation of turves were not suitable. Spore translocation offered a low-impact solution that satisfied both the council and the landowner and, hopefully, will have led to the successful translocation of the waxcaps affected by the link road.

The resulting challenge was a lack of precedent for this approach, as the normal method to date has been the translocation of large turves. Even this common method is still not regarded as leading to a certain outcome by experts like Dr Gareth Griffith at Aberystwyth University (Griffith et al 2004).

View westwards across the northern part of the southern field in the early stages of construction during the embankment construction.

View westwards across the northern part of the southern field in the early stages of construction during the embankment construction.

Previous waxcap translocation attempts

Attempts at translocating grassland fungi such as waxcaps have no proven track record of success, with previous attempts involving moving large turves so far failing to display evidence of success (Griffith et al, 2004). This may be due to the fact that underground mycelia can take over twenty years to reappear after disturbances (Griffith et al, 2004) to the extent that they can once again produce fruiting bodies.

However, success of translocation attempts can now be assessed by ‘bar-coding’ soil samples using eDNA for the presence of waxcaps in grassland. This can be used to demonstrate successful translocation prior to fruiting bodies being produced by the colonies.

Translocation using spores

This low-key translocation used a unique proposal: translocating only the spores of the waxcaps, rather than the turf containing waxcaps. This met the requirements of the mitigation area’s landowner, who would not allow turve translocations due to the potential for site damage from heavy machinery.

Previous surveys had identified locations within the management agreement mitigation area with similar vegetation to the waxcap-rich site that would be lost, but where there had been no evidence of fruiting waxcaps found since surveys began in 2003. The supposition was that these vacant locations could theoretically be colonised by transferring spores from donor areas.

Air photograph showing the location of each coloured waxcap from the donor area and the receptor area (starred to the north). The central section is now where the road is.

Air photograph showing the location of each coloured waxcap from the donor area and the receptor area (starred to the north). The central section is now where the road is.

This approach is based on the premise that waxcaps tend to nestle in the grass, which gives limited opportunities for the wind to carry their spores further afield. Therefore, the vacant areas may have no waxcaps because wind dispersal has been restricted. Subsequently, it was believed that artificially moving fertile caps into these vacant areas by allowing spores to be shed directly into the receptor areas could theoretically have a good probability of creating new waxcap colonies, particularly given vegetation similarities between the sites.

Method

Donor sites were visited weekly from the beginning of September into early December 2014, at which time the frosts halted any cap production. These searches made use of initial surveys previously undertaken in order to identify species presence within the donor and receptor areas.

At each session the candidate donor areas were slowly walked in a zig-zag pattern with each leg approximately five metres from the previous. As some caps were very small and difficult to spot amongst the turf, keeping the survey legs close together ensured good detection rates. The path taken was repeated weekly using a GPS track back function to follow the previous route as closely as possible.

Typical donor cluster of waxcaps (these are Hygrocybe virginea)

Typical donor cluster of waxcaps (these are Hygrocybe virginea)

The location of each donor cap or caps (often small colonies of five to twenty caps were found close together) was recorded as a waypoint on a GPS device and the number of caps and their species recorded. The caps were collected by cutting the stalk with scissors and placing them in a garden trug in species groups. There is debate as to whether pulling a cap out of the ground damages the mycelia below so, as a precaution, it was decided to cut the caps in this instance. The caps were separated into species groups to make it easy to apportion representative numbers of each species collected to each receptor location.

At the donor sites, all sporulating fruiting caps of any waxcap species visible were collected, varying in number from tens to hundreds on each occasion. Confirmation of the sporulation of caps was carried out by making spore prints during fruiting in 2013 of caps at different stages of expansion to judge the optimum size that would indicate ripeness and spore-shed. On each collection only those caps estimated to be at optimum expansion were collected. Waxcaps develop caps mainly during the autumn, so collections were made between 19 September (before the first caps emerged) and 4 December (when the number of caps had declined to very low numbers due to the cold weather). This was timed to ensure that early species and specimens were not missed. During the collection period, the number of caps of each species varied on the collection days. Generally, species gradually increased in number and tailed off slowly. Some species only occurred on one or two occasions, such as H. calyptriformis and H. splendidissima that were found on only two and one occasions respectively.

A typical mixed collection of caps in a trug

A typical mixed collection of waxcaps in a trug

The actual translocation itself was carried out by moving sporulating waxcaps to receptor sites, where they were placed gill-side down to allow them to shed their spores naturally into the receptor turf.

The number of locations from which caps were collected and the numbers of individual caps collected for each species during the collection window of 19 September to 4 December 2014 are shown in the table below.

Species No. of locations Total No collected
H. calyptriformis 2 2
H. Chlorophana 17 79
H. coccinea 8 19
H. conica 27 185
H. irrigata 5 13
H. pratensis 31 47
H. psitticina 182 546
H. splendidissima 1 1
H. virginea 166 480
Total 439 1372

The total number of caps (of all species) available changed across the collection window. The peaks for individual species show that some species, such as H. conica, began fruiting late, fruited well, then declined rapidly over the next few weeks, as the table below shows.

Collection date Total no of caps collected
19-09-2014 5
24-09-2014 2
01-10-2014 1
10-10-2014 3
17-10-2014 17
22-10-2014 59
28-10-2014 164
04-11-2014 332
13-11-2014 242
20-11-2014 353
24-11-2014 140
04-12-2014 60

Depending upon the number of caps collected at the donor site each week, between one and five receptor spots were used to receive the caps. These were spaced out within the receptor area to about three to five metres apart. At each receptor point, a proportion of each species of waxcap collected were placed gill-side down. The caps were carefully set down within an area of roughly one square metre with a distance between caps of around ten to fifteen centimetres. Only two caps of pink waxcap were found and both were translocated.

Typical receptor location showing the GPS and scissors used to cut the caps

Typical receptor location showing the GPS and scissors used to cut the caps

The future

This translocation was carried out in autumn 2014, so success cannot yet be judged. The site will be monitored for the next 20 years of the management plan and funding for future eDNA analysis is hoped for. We know that waxcaps can form new colonies from spores (Griffith et al 2004) and, as we are depositing concentrations of spores into comparable receptor areas, we feel that the probability of success is high.

Barry Wright comments: “Going forwards the aim is to eDNA barcode the donor areas, receptor areas and the remaining vacant areas that have not received the ripe caps and compare waxcap presence. I hope to answer questions such as: Are the vacant areas truly vacant? Did they already have the full suite of species we translocated into the receptor site? Have the spores deposited from the donor site germinated, in which case can they be detected in the receptor sward yet?

“This analysis will allow us to detect success or failure in advance of any colonies becoming established enough to produce fruiting bodies, which can take more than twenty years. While it is still too early to make conclusions regarding the future potential of this novel approach to waxcap translocation, it is hoped that this technique could become an accepted approach in the future and one that I hope other ecologists will take up”.

References, further reading and notes

Boertmann, D. (2010). The genus Hygrocybe: Fungi of Northern Europe Vol. 1: Revised second edition. The Danish Mycological Society.

Buczacki, S. (1992). Mushrooms and Toadstools of Britain and Europe. London: Harper Collins.

Griffith, G. W., Easton, G. L. & Jones, A. W. (2002). Ecology and diversity of waxcap (Hygrocybe spp.) fungi. Botanical Journal of Scotland 54: 7-22.

Griffith, G. W., Bratton, J. H. and Easton, G. (2004). Charismatic megafungi – the conservation of waxcap grasslands. British Wildlife 16 (1), pp. 31-43. Rotherwick, Hampshire: British Wildlife Publishing.

Griffith, G. W., Gamarra, J. G. P., Holden, E.M., Mitchel, D., Graham, A. and Evans, D. A. (2013).  The international conservation importance of Welsh ‘waxcap’ grasslands . Mycosphere, 4 (5): 969-984

Ing, B. (1992). A provisional red data list of British Fungi. The Mycologist 6: 124-128.

Ing, B. (1993). Towards a red list of endangered European macrofungi. In Fungi of Europe: Investigation, Recording and Conservation, pp. 231-237. Edited by D. N. Pegler, L. Boddy, B. Ing & P. M. Kirk. London: Royal Botanic Gardens, Kew.

Kibby, G. (2002). Recording sheet for Boletes. Field Mycology 3, 77.

LBP (May 2001). Lancashire’s Biodiversity Action Plan. Wildlife Trust, Lancashire County Council, English Nature, Lancashire Environmental Fund.

Phillips, R. (1994). Mushrooms and other fungi of Gt Britain and Europe. London: MacMillan.

Plantlife (2003). The Pink Waxcap Survey, Plantlife.

Rotheroe, M. (1997). A comparative study of waxcap-grassland fungi of Ireland and Britain, pp. 1-8: JNCC.

Rotheroe, M. (1999). Mycological survey of selected semi-natural grasslands in Carmarthenshire. pp. 14: Countryside Council for Wales.

Saunders, E. (2002). Entoloma Field Characters. Field Mycology, 3, 48.

Section 41 and 42 of the Natural Environment and Rural Communities (NERC) Act 2006 – Habitats and Species of Principal Importance in England. Available here.

Versions of this article are featured in the August 2015 edition of British Wildlife magazine and the September 2015 edition of CIEEM’s In Practice magazine. During the initial stages of the project, Barry was consulting ecologist for the project developer ADAS.