Saturday, 29 July 2017

What are the important characteristics of a roadside verge

Following up on yesterday's post, I did a quick bit of thinking about the features that might contribute to a scoring system for roadside verges:
  1. Width (the bigger, the better)
  • 0
  • 1-2m
  • 3-5m
  • 5+m
  1. Hedge present (important buffer from usage further back)
  • Narrow (<1m), tightly trimmed
  • Narrow (<1m), gappy
  • Broad (>1m), tightly trimmed
  • Broad (>1m), Bushy
  1. Hedge composition (potentially important as both nectar source and food source for birds)
  • Monoculture
  • Narrow range of species (2-3)
  • Broad spectrum of shrubs and woody climbers
  1. Trees in hedge (may have a positive or negative influence on ground vegetation and overall ecology)
  • Recent planting
  • Mature with potential/actual saproxyic features
  1. Ditch present? (Important and potentially valuable structural variation)
  • With water
    • With wetland plants such as Typha and Mentha aquatica
    • Manicured
  • Dry
  1. Bramble and/or thorny species in the sward? (Negative impact - risk of swamping of open grassland features)

  2. Recently planted woody species? (Potentially negative impact on grassland features)

  3. Vegetation composition (important from both a strictly floristic perspective as well as for invertebrates)
  • Rank, MG1 or similar
  • Composed of 'finer' grasses with range of specialist phorbs
  • Presence of local or 'rare' plant species
  1. Supports good nectar sources:
    • Hogweed
    • Angelica
    • Upright Stone Parsley
    • Cow Parsley
    • Ground elder
    • Hemp Agrimony
    • Meadowsweet
    • Field Scabious
    • Devil's-bit Scabious
    • Knapweed
    • Creeping Thistle
    • Rough Hawkbit
    • Ragwort
    • Fleabane
    • Sow thistles
    • Creeping/bulbous buttercup
    • Dandelion
    • Mentha sp.
    • Vetches
    This is just a quick bit of thinking to try to come up with a way of scoring verge attributes, both positive and negative. It has largely been constructed from a Dipterist's perspective and I am aware that I have probably overlooked important nectar sources for Hymenoptera.

    Anyway, it is something for discussion by others. Meanwhile, I think I might perhaps give it a try! Turning it into an assessment tool is a bit more of a challenge but it seems to be a potentially worthwhile exercise.

    Friday, 28 July 2017

    Managing roadside verges

    In most recent years there have been aggrieved posts on the UK Hoverflies Facebook page lamenting the cutting of a favoured roadside verge or patch of hogweed. Quite right too! Roadside verges are a fantastic nectar source for all manner of insects and in some parts of the country (such as much of Lincolnshire) are probably THE major wildlife resource. Loss of this resource in July or August might well have a significant impact on insect numbers and may contribute to the overall decline in wildlife that we have seen in recent decades. The issue is, however, a lot more complicated than at first might appear.

    Let us start with the importance of roadside verges. In a landscape where fields are cultivated right up to the hedge line, verges provide the few bits of wild space and a lot of landscape connectivity. In some places, such as the areas around me in Stamford, they are immensely rich and display remarkable floristic diversity. Some are so rich that they have been designated SSSI in their own right. They definitely need protecting and conserving, but how do we do this efficiently?

    I am fortunate to live in an area where there are great wide drove roads with wonderful wide flowery verges. But, droving has long since passed into history and unless some other form of management is implemented, there will be a change from open grassland to scrub. Mowing is the only realistic answer.

    Unfortunately, mowing is expensive and requires organisation. The first concerns of those responsible will not be wildlife. Their concern is that sight-lines need to be maintained for road safety. They will want to minimise cost, so if sight lines are unimpeded then verges won't get cut. If they are impeded the critical issue is to get them cut. It does not matter what time of year that happens – it just needs to happen. So, if you have contractors that can do the job in July, then that is when you do it. Never mind that in doing so you remove all of the essential nectar sources for insects. Equally, if you can get hedges cut then cutting in October is of little consequence even if it removes food sources for birds!

    We know the problem and I feel sure that many in wildlife organisations are perfectly aware of the issue. The big question is what can be done to change existing modus operandi? Well, maybe it is time to start to develop a register of important roadside verges; not just those with designations? Perhaps this is something that could be done by volunteers using a graduated scale? Then, perhaps there is scope for working with the Highways Agency and local authorities to change working practices? Perhaps too, there is a case for using agri-environment money to make the essential changes and perhaps also to make sure that all verges get cut completely at the right time of year, rather than being left to turn to scrub?

    I see a really nice project in the making – one that might generate a great HLF bid to combine the power of volunteer recorders with the influence of initiatives to improve pollinator numbers. There is something for the Wildlife Trusts to ponder. It requires a lot of skills and needs to involve botanists, ornithologists and entomologists. It could be exciting and might just make a difference.

    Saturday, 15 July 2017

    Key points in the evolution of the Hoverfly Recording scheme

    My last post elicited a number of threads of comments so I thought it might be helpful to chart the key stages in the scheme's development. The HRS was one of the first Diptera schemes and is now very much the flagship for British Diptera and Dipterists Forum. Its path has not always been smooth, and there are some important lessons to learn from the process. I have annotated the chart of total records per year to highlight key stages:

    Figure 1. Numbers of records for each year class since 1950
    1. The HRS was established in 1976 with Dr John Ismay (now specialist in Chloropidae) as its organiser. Dr Philip Entwistle replaced John some while later (I don't have the date for this) and ran the scheme until he retired from the Institute of Virology in 1987. When the scheme was launched, the only key was the RES key by Ralph Coe, which was very difficult to use, and highly out of date. Any serious student of the family had to use this in conjunction with numerous papers describing additional species.

    During this time, data were trawled from the collections of active dipterists of the day, and a small amount of data was extracted from museum collections. No formal programme of data extraction from museums has ever taken place and it remains one of the big jobs on the list. Likewise, there has never been a formal process of extracting data from journals, although some local groups have done this for their 'patch'.

    2. Stubbs & Falk's British Hoverfies: an illustrated identification guide was published in 1983. It resolved many of the critical problems with the literature and set the scene for a new approach to keys including thumbnail sketches for critical features. It was a game-changer in many ways and has become the model for most modern keys. In doing so, it opened up hoverflies to a much wider audience and interest in hoverflies grew substantially. The original print run was 1,000 copies: that rapidly sold out and a second print run was produced that incorporated a supplement detailing new species and new information.

    3. Around 1986 there was a 'call for records' in anticipation of production of a 'provisional atlas'. This led to a major push to improve coverage and resulted in a big spike in recording in 1987. However, at this point Philip Entwistle retired and also stopped running the scheme. Graham Rotheray took over as Newsletter editor but there was nobody at the helm of the scheme and interest rapidly waned.

    4. In 1991 Alan Stubbs persuaded Stuart Ball and Roger Morris to take on the scheme. The task was daunting because some 2 cubic metres of record cards had been amassed but there was no chance of their ever being computerised by BRC Monks Wood - they simply did not have the resources and there was ongoing austerity in funding for natural sciences. SB & RM therefore took the job on knowing that they would have to do the computerisation. It took 5 years. Some renewal of interest in hoverflies was stimulated but many of the most capable dipterists had become interested in other families and there was only a small blossoming of effort.

    5. By 1997 the data were in order and it was possible to draft a 'provisional atlas'. Once drafted it took two years to get to the printers and was finally published in 2000.

    Between 1998 and about 2005 SB and RM were not terribly active in promoting the HRS - various events influenced this period (RM being far from well). Furthermore, time was required to completely revise Stubbs & falk into the 2002 version that is available today.

    6. Around 2005 SB and RM realised that there was a need to reinvigorate the scheme and to give it impetus early indications of a proposed revised provisional atlas were circulated amongst scheme members. At this time, nearly all communication with recorders was via the Hoverfly Newsletter that was issued twice-yearly. Around the same time, it was also realised that the 'old guard' of recorders was becoming aged and a new generation was needed. More emphasis on training was therefore part of the initiative. At this point we did not have the capacity to provide microscopes so courses could only be run at venues that could provide microscopes.

    Around 2008-2009 the OPAL project was launched. It provided small grants to assist schemes and the HRS applied for funds to buy microscopes and to print teaching material. In two tranches, 13 teaching microscopes and camera microscope were purchased. This package has been the key to SB and RM running courses the length and breadth of the country. No count of courses or students has been kept so the absolute numbers are uncertain. However, it is estimated that around 400 people have attended hoverfly courses and probably a further 150 have attended the introduction to families course.

    7. The second 'provisional atlas' was published. Originally planned for 2010 it finally emerged in conjunction with the 7th International Conference on the Syrphidae held in Glasgow. Work on this atlas stimulated some additional effort, but the big improvement in data arose when Kenn Watt was persuaded to join forces so that his Scottish data could be merged with the HRS data.

    Since 2011 the HRS has been comparatively more active. Apart from training courses, SB and RM have spent a fair amount of time 'square bashing' in remote places. We started doing this from around 2004, with a major expedition to Harris and Lewis in 2006. RM has also done a significant number of trips alone.

    8. in 2013 two events completely changed the way hoverflies were perceived amongst natural historians. Firstly, a new indroductory guide in the WILDGuides series was published. The UK Hoverflies Facebook group launched a few months later.

    Membership of the FB group has grown exponentially and now stands at around 3,070. This initiative has seen the numbers of records entering the scheme grow very substantially, but only because RM has made a serious effort to ensure that data are extracted from the FB page. This growth in interest and effort has also led to changes in the organisation of the HRS. The scheme is now run by a group of eight: Ian Andrews, Stuart Ball, Joan Childs, David Iliff (Newsletter editor), Judy McKay, Roger Morris, Ellie Rotheray and Geoff Wilkinson. We anticipate that the suite of organisers will have to grow yet more because there is so much to do.

    There have been plans to revise the 'provisional atlas' and that remains a key objective that SB and RM are working on at the moment. Quite when it will emerge is as yet uncertain!

    Friday, 14 July 2017

    updated hoverfly records

    All of the data extracted and received for 2016 have now been uploaded into the HRS database. They largely speak for themselves but I thought it was worth doing a short piece to explain the graph and maps. Almost 52,000 records were added this week, mostly covering records from 2016 but also a few dating as far back as 2005.

    The headline really should real HRS reaches 1 million records, but we fall a bit short of it officially (there are about 5,000 2016 personal records on my database still to go in). As it stands, the database currently holds 994,838 records. There is about 10% duplication within the dataset so the true number of 'unique' records is probably about 900,000. That leaves us a bit short of the million in strict terms but at the current rate 1 million 'unique' records should be achieved within the next two years, and 1 million records in total will be reached very soon – just as soon as I sort myself out and download my data to Stuart (just over 5,000 records for 2016 and a further 3,000 for 2017). I will also pass on the data I hold for 2017 so I suspect the total will reach 1,010,000 records in a few weeks time. The other big omission from these data is records submitted to LRCs - at some point Stuart will do a trawl of new data on the NBN.

    This upload included MapMate synchs but not data on iRecord which we have still to work out what to do with. iRecord data cause us a bit of a problem because a LRC that shall be nameless uploaded its entire dataset and flooded it with data that we already have but that now we are not sure which to use – there is an awful lot of cross-checking to do before we can extract those data that are genuinely new and those that are re-determinations and queries. Even so, I think there are probably around 12,000 further records within iRecord to incorporate.

    The most obvious feature of the data is the dramatic rise in the number of records received since 2013. The top four peaks for the most records received fall into the years 2016 (53,669); 2015 (48,708); 2014 (41,917); 1987 (39,442) respectively. We know the 1987 peak was stimulated by a 'call for records' in advance of atlas production that took a further 13 years to materialise!
    Figure 1. Total yearly records within the database. The HRS was launched in 1976 and a major boost to recording occurred with the publication of Stubbs & Falk in 1983.
    The current peaks can be attributed entirely to the UK Hoverflies Facebook group. It really goes to show what can be done when schemes encourage participation by people who might not be traditional recorders. As I recall (without going back to data) data extracted from FB probably comprises about 60% of the data received in the last few years (I must get Stuart to do a chart). This is reflected in the numbers of contributors to the dataset, up from 8,482 in 2016 to 8,865 now.

    Coverage in 2016 shows that there is much more to do, with most recording concentrated in England. To a great extent this reflects the centres of population which inevitably means that recording effort will be more concentrated. A lot of Central Wales is both sparsely populated and difficult to work because easily accessible sites are more scattered and the geology is unhelpful (very poor acid conditions that limit species diversity). The same holds for much of Scotland, but it does surprise me just how few records we get, comparatively speaking.

    The coverage maps are, however, simply a snap-shot of one year's effort and over a series of years the gaps do get filled in to a large extent. Nevertheless, there will be parts of the county where there will always be a shortfall in coverage without deliberate 'square-bashing' – something I have tried to do over the years, but I fear my efforts will be severely curtailed for the foreseeable future.
    Figure 2. Record coverage (all sources) for 2016.
    Figure 3. Number of species recorded from individual 10km squares in 2016.