Milden Thicks SSSI is a series of privately owned woods in the parishes of Milden and
Little Waldingfield near Monks Eleigh. Woodland in this part of Suffolk
is now reduced to isolated fragments within a largely arable
landscape and in such circumstances the value of each individual wood as
wildlife habitat is reduced. One reason for this is that the species present
within a particular wood are cut off from populations in other woodland
and so are more vulnerable to extinction.
On their farm at Milden Hall,
Christopher and Juliet Hawkins are doing their best to reduce this
fragmentation by attempting to reinstate woodland on a 5.6 hectare field
adjacent to Long Wood (designated part of the SSSI). The new woodland will not
only more than double the area of Long Wood but will also reconnect it with Stattles
Grove, a small wood at present not designated part of the SSSI.
Nineteen SNS members visited Long Wood and the surrounding area on 7th June 2003 and twenty returned on 7th September 2003 in order to record the natural history of both the recently sown woodland and the more ancient woods surrounding it. It was hoped that by recording over these two seasons a considerable database could be amassed to provide a baseline for future studies of the development and colonisation of the new woodland. Long Wood and the newly sown field were recorded on both visits. In addition, Stattles Grove was visited in June and Hazel and Hall Woods were visited in September. Some members also recorded the flora and fauna of the farmyard and of the hedges along the tracks leading to the woods. Despite the presence of some interesting species the warm, dry weather throughout the summer and the relatively dense and unmanaged nature of the ancient woods seemed to have a negative impact on the total number of species, especially invertebrates, that were found. Most of the recorders agreed that Long Wood in particular would be a more favourable habitat for their group with a little more intervention from the owner.
The only mammals seen around the woodlands were hare and brown rat but signs of three others in the form of fox scats, a badger latrine and fresh molehills were also noted. Tadpoles of the common newt were seen in three of the four ponds investigated by Adrian Chalkley. Moth recording was restricted to daytime activities so a relatively short list of species was produced but several SNS members were delighted to see the humming-bird hawk moth in Long Wood.
The most interesting of the diptera recorded from Long Wood were the hoverflies Volucella inflata and Volucella inanis, the latter also collected in Hazel Wood. The hoverflies of this genus mimic bumble bees or social wasps and females of four of the five species thereby gain entrance to the hymenopteran nests to lay their eggs. The larvae are generally scavengers feeding on the debris (and its associated fauna) within the nest, even after the bees and wasps have left in the autumn. A variation on this life style occurs in one of the species. The larvae of Volucella inanis are ectoparasites on social wasps including hornets. Morris and Ball (2003) have recently described a contraction in the British distribution of this hoverfly prior to 1960. The species was largely confined to southern England even before this contraction and Suffolk has always been on the northern edge of its range. However, from 1990 there was a northward expansion in range and by 2001 the hoverfly had reached Nottinghamshire. It has been suggested the reasons for this are climatic and may be associated with the expansion in range of the hornet. However, the answers are not so clear-cut as the hoverfly has not returned to its former sites in the South West and it has appeared in areas where the hornet does not occur. There are still only a handful of records of Volucella inanis in Suffolk and there remains plenty of scope for a local naturalist to provide significant insights into the ecology of this species through careful observation and recording.
Volucella inflata deviates even more than V. inanis from the typical lifestyle pattern seen within the genus. Females have been observed laying eggs in sap runs on tree trunks and larvae have been observed feeding at the same sort of sites. As these sap runs tend to be more common on mature and over mature trees this hoverfly is closely associated with older woodlands. There is a handful of old records (pre 1960) of this species from Suffolk but the Provisional Atlas of British Hoverflies shows no recent records for the county and attributes its scarcity in East Anglia to the paucity of woodland.
There have been a number of attempts to use beetles as indicators in assessing the status of woodland habitats. As a result lists now exist of the species of beetle that are commonly associated with woodland and these also indicate how strong the association of each species is with ancient woodland sites. Most of the nationally scarce beetles collected during the meetings in Milden Thicks are considered to be woodland specialists but, although collectively these species may be typical of ancient woodland, none of them are considered to be restricted to such woodland. The most significant beetle find was that of Tetratoma ancora which has not been seen in Suffolk since it was first collected near Bungay around the 1850s. The beetle appears to be associated with fungi that infect decaying timber and David Nash commented that it also appears to be linked, but by no means exclusively, to hornbeam woodland. •Just one nationally scarce species of beetle was collected from the newly planted woodland. This was the flea beetle Longitarsus ganglbaueri which feeds on ragwort (Senecio sp.) in a range of disturbed sites. Although the beetle has previously been recorded from East Suffolk this was a new record for West Suffolk. It also raises a conservation dilemma in terms of whether the new woodland is of more value than the disturbed ground it is replacing. It could be argued that areas of disturbed ground with the relevant food plant are in abundance for this beetle but clearly not many such sites are suitable if it remains nationally scarce. It would be interesting to know how widely distributed Longitarsus ganglbaueri is on Milden Hall farm and adjacent land.
On the botanical side the most interesting record was that of the moss, Brachythecium populeum. Richard Fisk found this species growing on a tree root on the edge of Long Wood. Although not a nationally rare species this bryophyte is scarce in Eastern England and there are only six records from Suffolk. In the Norfolk flora Robin Stevenson declared it to be very rare and cited only one recent record.
In summary, as might be expected at this stage of the experiment the newly sown field supported a very different community to the surrounding woodlands. Whilst this community may have been very diverse e.g. 103 species of flowering plants compared with just 82 in Long Wood, it generally lacked species of conservation interest (with the exception of the flea beetle Longitarsus ganglbaueri). Such species were mainly associated with the woodlands and it is just these organisms that the experiment is intended to benefit. It will be interesting to see how long it takes them to become established as the new woodland matures. In theory the more common woodland species, such as the speckled wood, are likely to move in fairly quickly but any colonisation by supposed ancient woodland indicators would not be expected within our lifetimes. Will this be the way the area is colonised in practice? We may start to get some of the answers when the SNS return to the site for another field meeting in 2008.
Acknowledgements
Thanks to Juliet Hawkins for making all the arrangements with the landowners to visit the woodlands and for allowing use of the farmyard for parking and use of the toilet facilities in the barn. Adrian Chalkley, Richard Fisk, Justin Gant, Stuart Gant, Colin Hawes, Alan Hubbard, Paul Lee, Rob Parker, Tony Prichard, David Nash, Barry & Jane Ruggles, Neil Sherman and Arthur Watchman supplied records and comments. Copies of all of the records submitted to me have been supplied to SBRC and to the relevant landowners.
Reference
Morris, R.K.A. & Ball, S.G. 2003. The changing distribution of Volucella inanis (L.)
(Diptera: Syrphidae). British Journal of Entomology and Natural History 16 (4): 221-227.
Paul Lee, Oakdene, The Heath, Tattingstone, IP9 2LX
On a cool and damp Sunday in the middle of summer twelve members and two guests defied the odds against fine weather and thoroughly enjoyed themselves. The primary objective of this workshop, organised by Michael Kirby, was to study a range of plant galls and look at their causative agents. There was more to it than just collecting and identifying. Microscopes and other accessories were provided to examine the external and internal features of a range of galls, along with a good collection of guides and keys and, most important of all, experts to help.
The event was held in Dunwich Reading Room, a very suitable venue. The morning session offered opportunities to learn. Spangle galls (three species), marble galls, nail galls, artichoke galls and others, on a range of plants such as nettle, oak, goat willow and lime were examined. The mixture of novices and specialists worked well, the latter providing guidance for the former in a relaxed and friendly way.
Not all questions were answered however, particularly those concerning detail of how gall-causing agents stimulate the changes in the normal morphological development of plant tissue to produce the gall structure. So there is plenty left to study for those with an appetite for investigation!
After lunch the group went into the forest nearby to look for ant lions. No one appeared to notice the precipitation, including the ant lions. We were fortunate to see a large number of pits under the eaves of the sandy banks, one of which housed a larva in the process of grabbing a wood ant. Michael’s running commentary was clear and illuminating, especially details of the ant lion life cycle and his study of their behavioural responses to high temperatures. Apparently in the USA ant lions are known as ‘doodlebugs’ because of the concentric patterns they make in the sand of the cone-shaped pits they dig (using a corkscrew-type movement of the posterior end of the abdomen). We also learned that they are good at weight lifting as they regularly eject large grit particles or other debris many times their own size, throwing them several centimetres out of the pit. Joan Hardingham turned out to be an ace at spotting the pincers of the larvae projecting from the bottom of the pits. Some serious gall hunting followed. Specimens collected were taken back for further study to the reading room where a cup of tea and a chance to dry out were gladly accepted.
As often happens on these occasions someone finds something unexpected to get excited about – this time it was a very small form of Cat’s-ear in the forest ride. The meeting was a departure from the normal format. Everyone enjoyed it and I learned a lot.
David Walker
© 2004 Suffolk Naturalists' Society
used by kind permision.