Aliens in Cheshire!
by Clive Washington
A few years ago I had been surprised to find a flattish yellow sluglike creature, about two inches long, under a stone in my garden. A bit of research showed that it was the Australian flatworm, Australoplana sanguinea, an alien species which appeared in the UK (in the Scilly Isles) in 1980, but has since been found across the country. There is some concern about these flatworms as they are earthworm predators, and DEFRA advice is to trap them with flat refuges and destroy as many as can be found. They are listed on schedule 9 of the Wildlife and Countryside Act, which makes it an offence to deliberately release them into the wild. This winter I've seen a few more, in the same spot in my garden, but this time I had my camera to hand and was able to observe the creature closely. Reminiscent of a leech, it stretches its head end out and waves it over the surface in a search pattern, looking, presumably, for its prey, or indications of it. After a few minutes it must have found some sort of trail because it turned round through 180 degrees and headed directly towards a worm-hole in the soil substrate. It disappeared down the hole in about a minute, presumably in search of its prey, and didn't emerge in the half-hour that I watched afterwards. The following evening I encountered two more, which are now in a moss-filled pot in my office, waiting for a suitable experiment to suggest itself!
One of the questions I am most frequently asked is, what is the reason for an amateur to study natural history? Surely you can't contribute anything useful without a professional qualification, or being affiliated with a university or museum? Hasn't it all been discovered already anyway?
In fact natural history has always been the domain of the amateur, and the vast majority of what we know about life on this planet has been discovered by people who were not paid for their efforts and received no formal scientific education. This summer has produced, for me, a couple of good examples of how amateurs can contribute to knowledge, and why we should continue to encourage others to take part in our activities and develop their skills.
When I started moth trapping in 2008, I wasn't desperately interested in moths, but rather in all the other things that were attracted to light, the so-called 'by-catch', and primarily beetles. For example the carrion beetle Nicrophorus humator is a common visitor, which gets flicked away with a stick – you definitely don't want to handle one of these or your hands will stink for hours, and soap won't help. I've also had Curculio glandium, several Aphodius, Harpalus rufipes, and a few water beetles.
It hasn't been a good year for moths and the trap has been empty on many nights, but on the 2nd of June it was warm (for Warrington!) and I went out to check things around 10 pm. There were a few Diptera and not much else, then I saw a small beetle, cylindrical, about 6 mm long, which I didn't recognise at all, sitting on the crossbar directly under the bulb. If it had been anywhere else I probably wouldn't have seen it. So it got potted and I brought it inside.
A few minutes scanning the Internet (using the Kerbtier website, www.kerbtier.de which is well laid-out for this) brought me to Ernobius (Anobiidae) for which my only key was Joy. The first couplet says 'Th. strongly angled in middle of sides... so that hind margin is narrower than front margin... parvicollis Surrey, vr. This fitted my specimen perfectly but finding a rare Surrey beetle in my back yard was a bit unexpected, so it was off to the Manchester Museum a few days later, where Dmitri Loganov showed me his single British specimen of angusticollis (the name had changed) and some European specimens which were sufficient to convince me that I was on the right track. Don Stenhouse sent me a copy of the Ernobius key from Fruede Harde and Lohse which confirmed the antennal pattern (the sequence of long and short segments in the antennae are characteristic in many Anobiidae).
The potential rarity of this insect meant that I had to get a full verification, so it was sent to Howard Mendel at the Natural History Museum who dissected its genitalia (fortunately it was male) and confirmed that it was angusticollis. Even the NHM only have a single British specimen! There are only 5 records, all from Surrey, on the NBN Gateway. So we have a beetle that is rare even in its single southern habitat – and it turns up in my back garden in Warrington! What's going on? Like all good research it raises more questions than it answers, but one thing is for sure, it would never have been found without amateur effort.
The second discovery happened last weekend (the 22nd July) when I had dropped in to Rocksavage nature reserve for a casual field session while Andy was doing some management work. I had taken suction samples from a number of areas, and rather than sort them in a tray, I had simply dumped the lot into an extractor – a wire basket suspended over a bucket - to see what would fall through. A few ground beetles appeared but nothing significant, and I was about to empty the lot out when I noticed a bright green insect walking along the top of the bucket. "Hmm, that's a bush cricket", I thought, and as I knew absolutely bugger all about Orthoptera, I potted it, showed it to Andy, and took it home for a closer look.
Speckled Bush-cricket Leptophyes punctatissima
The FSC Orthoptera card keyed it out easily as a speckled bush cricket, which had no Cheshire records on rECOrd and only southern UK records on NBN. Andy phoned Paul Hill, who has been recording Orthoptera in Cheshire for years, who confirmed that it was a speckled bush cricket, and the first record for Cheshire. It has been recorded in South Staffordshire, and thus appears to be moving slowly northwards – probably due to global warming. Changes in distribution of this type are one of the most useful things that the amateur can contribute, and clearly show how warming is changing the distribution of species in the UK. As Rocksavage is in North Cheshire, it is likely that there are other sites for this insect in Cheshire and it's now up to us to get out there and find them!
(Of course the other question that the public keep asking me is if naturalists are people who take their trousers off in fields... No wonder the professionals coined the term ecologist...)
Our Noisy Neighbours And Their Offspring!
‘The pungent odour of guano and the guttural calls of seabirds’.
This sounds like the typical description of a coastal breeding seabird colony. However, it can also be applied to the edge of a Cheshire woodland bordering Rostherne Mere National Nature Reserve, approximately 45km from the nearest sea.
Rostherne Mere plays host to one of the region’s largest inland breeding Great Cormorant (Phalacrocorax carbo) colonies, which has witnessed a rapid expansion in only a few years.
Cormorants nesting at Rostherne Mere in May 2007 (Bill Bellamy).
Cormorants have sporadically bred inland in Britain for centuries but a marked acceleration occurred from the early 1980s. By 2005, breeding had been noted at 58 inland sites with the breeding population rising to at least 2,096 pairs. This figure actually exceeded the coastal total of 1,564 pairs (Mitchell et al. 2004, Newson et al. 2007, Norman, 2008). Interestingly, a number of the early inland nesting sites appear to have undergone a population decline in recent years.
In Cheshire, Keith Massey reported on the ‘First Nesting of Cormorants in Cheshire and Wirral in 1999’ in The Cheshire and Wirral Bird Report 2000. The location was Fiddler’s Ferry Power Station but the two eggs laid disappeared without a trace. It was five years later before Cormorants successfully bred in Cheshire, and amazingly simultaneously at four locations - Frodsham Marsh, Fiddler’s Ferry, Trentabank Reservoir and Rostherne Mere (Norman, 2008).
At Rostherne Mere, nesting first occurred in 2004 with 5 nests recorded. The graph below shows the rapid increase in nest building in subsequent years, with an amazing 160 nests logged in 2011.
Cormorants have roosted in a series of alders at the foot of Harper’s Bank Wood at Rostherne Mere for many years but these numbers have gradually built up in recent times, peaking at 457 birds in May 2011. This count was augmented by many of the young birds of Rostherne origin. With between 2 and 3 young in each nest, that is a lot of fish suppers for the parents to provide. It is thought that many journeys are made to and from waterways around the county and possibly beyond.
The number of Cormorant nests at Rostherne Mere 2004 to 2011. The trend line represents a moving average.
Monthly maximum counts of Cormorants roosting at Rostherne Mere 1976 to 2011.
As in many other sites, the first nest builders at Rostherne appeared to show typical plumage characteristics of the race Phalacrocorax carbo sinensis, showing extensive white on throat and forecheeks with conspicuous white plumes in a solid stripe on sides of the nape. As the colony has developed it appears the subspecies Phalacocorax carbo carbo has possibly become the major breeder. However, separating the races is extremely difficult and inter-breeding has also been reported from other sites (Newson et al. 2007).
Interestingly, an examination of breeding performance has shown that inland breeders have a higher nestling survival rate than coastal birds and they tend to breed for a more protracted period (Newson et al. 2005). At Rostherne Mere, the first nests are often visible in early February, supporting these findings.
Cormorant nests at Rostherne Mere from the safety of the reed bed (Malcolm Calvert).
After the chicks make their first tentative flights, they gather in large parties for fish catching practice. This can involve up to 60 birds which makes an incredible spectacle as they herd fish into the shallows. On occasion, the fish literally jump out of the water to avoid the predating pack.
As a final comment, a word of warning is required. After venturing slightly too close to the colony earlier this year during some scrub clearance work, I received the gift of the regurgitated head and guts of a large roach which descended from a great height. Others have said it was not intended but I’m not convinced!
Mitchell, P.I., Newton, S.F., Ratcliffe, N. & Dunn, T.E. (2004) Seabird populations of Britain and Ireland. T. & A.D. Poyser, London.
Newson, S.E., Marchant, J.H., Ekins, G.R. and Sellers R.M. (2007) The status of inland-breeding Great Cormorants in England. British Birds100: 289-99.
Newson, S.E., Hughes, B., Hearn, R. & Bregnballe, T. (2005) Breeding performance and timing of breeding of inland and coastal breeding Cormorants Phalacrocorax carbo In England and Wales, B.T.O., Bird Study, 52,10-17
Norman, D. (2008) Birds in Cheshire and Wirral, A breeding and wintering atlas, Liverpool University Press, 162-163.
The Recipe For A Special Hot Pot!
The 10-spot pot beetle (Cryptocephalus decemmaculatus) is a bit of a mouthful and it is also very rare. The only known site for this leaf beetle in England is within the 16.5 hectares of Wybunbury Moss National Nature Reserve (NNR), located towards the southern border of Cheshire .
Cryptocephalus decemmaculatus. The beetle to the right is a lone male who will shortly attempt to cut-in on the mating pair (Ross Piper).
There are nineteen Cryptocephalus species found in Britain and many of them are of conservation concern. The adults of the genus are fully winged, thermophilic and can be found perching on their respective host plants. They have a fascinating life cycle in which the female beetle encases each egg she lays in faeces. The eggs are dropped onto the ground and, once hatched, the larvae adds to the egg case to form a larval case, which it carries around and retreats into at the first sign of danger. Larvae of all the species feed on leaf litter, making them vulnerable to habitat ‘clean-up’ management. They eventually pupate from the larval case and make a short flight up into the leaf layer.
Cryptocephalus decemmaculatus is a yellow, black spotted leaf beetle. The adults are small (4-5 mm long).
Dr Ross Piper is an expert on the genus and has made some very interesting discoveries about Cryptocephalus decemmaculatus, finding that the beetle depends upon dynamic scrub transition and adults are found predominantly on small Salix spp. trees invading areas of wetland. The beetle moves through its habitats using suitable host-plants as ‘stepping stones’. These beetles cannot fly well and there appears to be no interchange of adults between sub-populations that are separated by small areas of unsuitable habitat, a deduction reinforced by other studies of their genetic differentiation over distances as small as <1km.
Ross believes that the beetle population at Wybunbury Moss was isolated when surrounding land made way for agriculture, many thousands of years ago or possibly even when the surrounding land became drier in the post-glacial period.
Wybunbury Moss in July 2008 before recent tree removal to prevent the Moss drying out (Bill Bellamy).
Wybunbury Moss is one of only two types of special ‘subsidence formed moss’ known to exist in the British Isles. Peat has been deposited in a glacial hollow but has actually formed a raft, in some places only a metre thick, which floats on a water-filled basin itself over 12 metres in depth. It is believed that the floating nature of the Moss may have been created by the subsidence of salt-bearing rocks beneath the Moss basin. The site is managed by Natural England.
During my involvement with Natural England, it has been fascinating seeing how the balance in habitat management is achieved with tree and scrub removal to reduce the drying out of the Moss whilst maintaining and encouraging the host trees for Cryptocephalus decemmaculatus. The objective is to provide habitat corridors for the beetle to move ‘via a series of short flights’ into different suitable areas of the Moss, thus making in less vulnerable to the vagaries of factors impacting micro-sites.
Wybunbury Moss, together with its surrounding woodland, reedswamp and flower-rich meadows also provides habitat for a rich variety of uncommon plants and animals, including two Nationally rare spiders.
Female Cryptocephalus decemmaculatus (Ross Piper).
Wybunbury Moss is, however, a dangerous environment and there is no general public access to the site. A public footpath surrounds the NNR, giving good views across the Moss. A visit to the site in September 2012 is included in the CAN Events Calender 2012/13 in which we will be venturing onto the Moss with guidance, so why not join us to experience this unique and special habitat?
While Cryptocephalus decemmaculatus is only known to be found at Wybunbury Moss, it is possible it could be present at other sites where there is scrub transition between woodland and wetland. Late May to early June is the best time of year to see the colourful adults so keep an eye out!
Many thanks for the information contained within this article to:
Dr Ross Piper
Ruper Randall (Natural England)