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 1987 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 When the scheme was launched, the only key was the RES key by Ralph Coe, which was very difficult to use, and highly out of date.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.

Wednesday, 28 June 2017

An exemplar of watch and record

This last weekend I visited John Bridges whose spectacular stacked shots adorn the UK Hoverflies Facebook page. John has been a passionate photographer for decades but as his mobility diminishes he has had to adapt to an increasingly difficult situation. It is hard for those of us who have no mobility problems to understand what it is like to have to stop every 20 or 30 yards to alleviate pain in one's legs; yet this is what John battles with each day. Nevertheless, he is dedicated to his cause and has developed an amazing ability to record hoverflies by photography and then retaining specimens for microscopic examination. In doing so, he has generated some impressive species lists for four or five locations within a five mile radius of his home in County Durham. The combined species list for these sites is now over 100 species, which that far north is impressive by any measure.

What really struck me about John's sites is how 'ordinary' they are! I don't mean that in a disparaging way – quite simply, they are sites that might be encountered in many urban and sub-urban settings. They are not top-quality nature reserves but include an urban playing field, a well-used plantation woodland that is afflicted by teenage firebugs and a steam down what appears to be a spoil tip. That said, two of them are a shade unusual because they lie in close proximity to the wonderful Durham coast where major efforts are ongoing to re-wild the land immediately to the rear of the Permian limestone cliffs. They include sections of old/ancient woodland that forms part of the classic 'Dene' landscape of the Durham coast: deeply incised wooded stream valleys.

John Bridges at work on the margins of the famous 'Dandelion Field' in South Hetton

John making best use of 'old faithful' at Grants Houses - a busy footpath that is a pretty familiar urban setting.
John's lack of mobility means that he cannot stray from the path and has to keep to a radius of perhaps 100 metres of his car. His limited mobility means that he pursues hoverflies in the full gaze of the public and is obviously a well-known local feature. Everybody knows him and stops to say hello. Whilst this approach to wildlife recording might not be everybody's cup of tea, it is one that might be followed by other people with disabilities.

I would really like to see a project developed to encourage the disabled to develop similar skills and interests: maybe a joint venture between wildlife organisations and a disabled charity? I think there is potential to develop a project that would attract HLF funding and might make a real difference to the lives of people with physical disabilities. In doing so, perhaps it would also alleviate some of the mental disability that can accompany physical problems. If somebody picked up the baton, I think it is essential that the project had at its heart a focus on helping the disabled as much as to improve biological recording. John has shown what is possible; perhaps others will follow his lead.

Damp situation at Horden with Equisetum telmateia - usually a sign of base-richness that can be great for soldierflies.

Sunday, 18 June 2017

What is involved in running a recording scheme?

Yesterday, a post on the UK Hoverflies Facebook page drew my attention to the possible need to set out what is involved in running a recording scheme. As a result, I wrote a quick list and then organised it according to a set of sub-headings. The list was quite a surprise to me because it really highlighted the depth and breadth of what was involved. My list covered all the jobs on the FB page and the others that go on in the background and comprised the following:

Identification service
  • Provide IDs for UK Hoverflies  and UK Hoverfies Larval groups .
  • Respond to ID queries by e-mail and by flickr pages.
  • Provide specimen identification service for non-academic recorders.
  • Provide specimen identification service for Universities.
Data management
  • Extract data from FB page- maintain yearly spreadsheets.
  • Chase posts that lack data.
  • Scan FB page each day to ensure all posts have been noted and responded to.
  • Trawl Flickr sites for records.
  • Trawl iSpot for data.
  • Check grid references and dates to make sure these are correct (get quite a lot in the sea!)
  • Digitise card data and e-mail lists to spreadsheet for upload to database.
  • Validate iRecord data.
  • Check over (validate) incoming spreadsheets and format them for upload (all sorts of permutations, including converting word files to spreadsheet).
  • Import data into HRS database.
  • Supply data to research groups and NBN.
General management
  • Provide sense of direction for the HRS.
  • Manage applications to join FB group.
  • Respond to e-mail enquiries from students and research groups – technical advice.
  • Develop & manage HRS website.
  • Manage applications to join HRS website and eliminate spammers.
  • Publicity for the Scheme .
  • Prepare intermittent feedback for Facebook group, including annual report.
  • Provide detailed responses to significant questions on FB concerning datasets/ecology etc.
  • Write HRS outputs (e.g. atlas) and evaluate maps to identify questionable records .
  • Write newsletter items (2x per year).
  • Conference presentations and talks to local societies.
  • Collect and prepare specimens for running training courses.
  • Act as interface with centres that want to run training courses.
  • Organise travel and accommodation for training courses.
  • Run training courses.
At the moment we have a team of eight: Ian Andrews, Stuart Ball, Joan Childs, David Iliff, Judy McKay, Ellie Rotheray, Geoff Wilkinson and, of course, me. Looking at what we do at the moment, it strikes me that the HRS has grown in a way that it is now analogous to a small society such as BWARS. The main difference is that, because we are not a subscription society, we don't have formal 'positions' that have to be filled. That is both an advantage and, possibly, also a drawback. On the plus side, we don't need formal officers such as 'secretary' or 'treasurer'; nor do we need committee meetings that are often highly time-consuming. On the downside, how do we ensure that there are democratic provisions so that the scheme does not become a personal fiefdom?

I am acutely conscious that I currently do a lot of the 'leadership' but that is by default and because I am naturally 'bossy'. It seems to work at the moment, but it also leaves a big question mark over the long-term organisation of the scheme. Stuart and I have now been at the helm for 26 years and we must start to think about a succession plan.

When we took on the scheme, it was moribund: the previous scheme organiser had retired and nobody had stepped forward to take over. Graham Rotheray took on the newsletter editorship (now David Iliff) but the scheme effectively died. At the time, recording schemes were a bit of a peripheral adjunct to wildlife conservation, but they now play a central role in the development of reliable wildlife data. The bigger schemes are mainly linked to formal societies (e.g. dragonflies and aculeate Hymenoptera). The HRS has links to Dipterists Forum, but the Forum has no say over the future of the scheme. This lack of oversight can be a problem because there is no way of replacing a scheme organiser who has ceased to drive the scheme. In the case of the HRS, we cannot afford to let things drift: hoverfly recording is so central to various initiatives, not least current interest in pollinators.

That makes me start to ask whether we should formalise the Scheme into a Society? My question at the moment is rhetorical, but it has a rationale. What happens when somebody wants to step down from a role? In a society, there is a mechanism for advertising for a replacement and a democratic process for making new appointments. In an informal recording scheme there is no such process. Who actually has a say in the replacements? Also, if there are formal roles, these can be quoted in people's CVs. This may be important for potential recruits amongst the younger generation who obviously need to show that they are doing something if they take on a role that may help to propel their career.

I leave this analysis as food for thought, but may return to it in due course.

Saturday, 17 June 2017

An insight into a day's square-bashing

For those who are unfamiliar with the concept of square-bashing, I thought it might be instructive to show how I approach the subject. The map below depicts the route I took on 9 June between Mallaig and Fort William. It involved a total of ten stops, mainly on roadside verges as real 'sites' are often hard to come by. Where I can, I try to stop by a stream or woodland so that there is potential to collect Nematocera for the Cranefly and Fungus Gnat schemes. In other places I stop for a matter of minutes when I spot somewhere that might yield a few hovers: after all, every record counts!

Map 1. Locations of sampling points when square-bashing on 9 June 2017. The first five sites took approximately 3 hours and the remaining sites were visited quickly on the return trip. I arrived at site 1 at around 10.15 and headed for home from site 10 around 3.45, reaching Kingussie at 5.45. The total round trip was about 180 miles. In the process, 6 ten kilometer squares were visited and a small number of hoverfly records was generated.
On this day, my aim was to cover part of the west coast that is very poorly recorded. The day was not ideal – a mixture of sunshine and showers – and there were very few nectar sources. So, apart from checking out the occasional roadside Rowan, it was a matter of sweeping to generate the majority of records.

Even so, I did find two very nice localities. The first was a lovely iris flush running to the shoreline, which is very characteristic of the west coast of Scotland Location 6 (photo 1); the second (Location 9, photo 2) was a delightful section of stream with adjacent meadows covered in pignut and with localised patches of brambles and dog rose. Both were pleasant and the second site yielded a reasonable list of hoverflies. Nevertheless, hoverflies were thin on the ground and I did far better for Nematocera.

Photograph 1. Flushed shoreline with iris beds abutting saltmarsh in a continuous transition.

Photo 2. Damp meadow with bramble and dog rose.

When recording Nematocera I simply hoover up everything that flies like a cranefly or gnat and then sort them when I get home. I often end up with a pooter full of small flies and refer to it as 'black grot' – which is frowned upon by Peter Chandler as he loves fungus gnats. Photographs 3 and 4 show the results – the pile of specimens for sorting, and the subsequent piles of gnats and craneflies. I'm afraid neither shot is terribly good as it was taken in the rather restricted light of my hotel room and there was probably an element of camera shake given long exposure time (I'm no photographer!). Out of this morass I also identify what I can from other families, and pin a small amount of specimens for identification in the winter (or a winter!). The end result often yields records of Lauxaniidae, Empididae, Dolichiopodidae, Tephritidae and Larger Brachycera, so lots of schemes benefit in the long-run.

Photo 3. Sample of flies collected before sorting. Whilst predominantly Nematocera (standard bird-food) there are also a range of other families and Orders, with a large green sawfly prominent on the right hand side, and several yellow Lauxaniids in the pile.

Photo 4. sample of Nematocera separated into craneflies and fungus gnats.
This is the sort of recording that others might wish to try. It is arguably the most effective way of making sure that one uses one's time efficiently and makes sure that as many schemes as possible benefit from what is a very expensive trip. I will post more on the results when I get data back from Alan and Peter.

Low-hanging fruits

It has always struck me that people such as me were probably born in the wrong century. So much is now known about the natural world that the cutting edge of ecology lies in DNA bar-coding and ecological modelling. The straightforward natural historian has a rather constrained palate and, although we might be just as competent as our forebears, our mark on history will be far less pronounced.

I am one of the lucky ones. I got into hoverflies at a time when they were still relatively unknown. By dint of good fortune and hard work, I have managed to make my mark in traditional aspects of natural history: expanding our understanding of the distribution and ecology of a charismatic group of animals. I cannot claim to have done this alone! Without Stuart Ball's phenomenal brain, I would never have made as much of the subject. But, this has left me wondering what there is to draw in the next generation? Where are the big gaps that they can address?

Natural history has evolved and will continue to evolve. New 'names' will become the leaders in the field, but they need a niche to get established. If the easy niches are filled, then how do they make their mark if they are not blessed with mathematical or computing prowess? Some may find potential in organisms that hitherto have received much less attention, but many of these animals are unlikely to gain wider attention, so there will doubtless be space to grow skills and to occupy the inquiring mind.

BUT, we do still need these brains to continue to look at popular taxa. Monitoring changes in animal and plant abundance and distribution is a fundamental part of monitoring the health of our planet. We need this as never before. Populations of invertebrates are declining at a frightening rate and we need to be able to articulate this and trigger changes in societal behaviour before the World becomes a dull and monotonous place that is devoid of those bright flashes of excitement.

We must therefore make space for the young and we need to give them the tools to get excited and committed. I see this as absolutely essential if we are to give recording schemes long-term sustainability. In this respect it seems to me to be essential that those of us who are well-established should be mentoring our possible replacements. We need to be thinking about the unanswered questions that could be tackled by our potential replacements. So, here are a few ideas:

  1. Developing detailed habitat-specific assemblage data. We have a broad picture of what occurs where, but can we start to determine whether there are particular levels of assumed phyto-sociology that are relevant to hoverfly populations?
  2. Understanding localised abundance of hoverflies and how this fits into modern thinking about 'landscape-scale' habitat restoration?
  3. Investigating mate-searching strategies – can we develop a clearer picture of the strategies species use, so as to understand the 'guilds' of behaviour. I think there are essentially three strategies: Territorial, Lekking, Active Searching. Some of these can be broken down into sub-classes. For example territorial species may occupy air-space or a vantage point. Do such species do both?
  4. Investigating new ways of identifying live animals. I think there is an awful lot still to do. We have grown used to the characters developed by past taxonomists that are based on preserved specimens and designed for identifying preserved specimens. BUT, live animal taxonomy IS different and to some extent unquantified and in need of description.
  5. Linking DNA analysis to high resolution morphological analysis to determine whether there are good characters at high magnification that will help to resolve conundrums in species determination.
  6. Understanding the way hoverflies (and other invertebrates) use the landscape matrix to disperse. What are the impediments to dispersal and at what scale do they become significant?
  7. Understanding host-parasite interactions. Each year there are differences in the abundance of individual species. Some of these differences may be climatic, but are there examples of parasites acting as a brake on populations? Intuitively, it seems likely that there are, but do we really know what they are? (this one could be nice for people who are interested in rearing larvae).
  8. Some basic ecology – finding larvae of species whose larval stages are as yet unknown. There are, I guess, 80-100 species in this category in the UK.
  9. Investigating the impact of altitude and micro-climate at a local scale to help to determine more about landscape changes that might be made to improve hoverfly abundance in the uplands.
  10. The value of different woodland types and layouts in uplands. This could be very valuable in helping to shape land management policies as marginal land becomes economically inactive.

This list was constructed after relatively little thought. Doubtless it could be expanded many times over, and critics will immediately say that I have not mentioned pollinators. I have not, for very good reasons: there are plenty of pollinator initiatives, but hoverfly ecology and taxonomy is about so much more than plant pollination! Equally, somebody will doubtless say that other elements of the list are already known; perhaps they are, as I cannot claim to be the font of all knowledge. But, if they are, then we need to make sure that the information is readily available to help policy-makers and practical ecologists use this information to conserve the natural world.

Tuesday, 13 June 2017

Square-bashing in Scotland - some basic statistics

Between 31 May and 10 June I made my way through Scotland, staying at four localities: St John's Town of Dalry, Moffat, Tarbet (Loch Lomond) and Kingussie. Conditions were far from ideal, with several spells of wet weather and most of the time there was a risk of rain. This severely attenuated what I had intended, especially my wish to do some serious recording at Rowan in the Spey Valley. It meant that I spent far more time sweeping and relatively little time watching Rowan flowers. The records reflected this, with Bacchines and Chrysogastrines dominating the catch Table 1).
Table 1. Composition of the records at Tribe level.

The dominant species in most samples were the genera Melanostoma, Platycheirus and Sphegina, which is not entirely surprising bearing in mind that sweeping tends to yield far more of these genera than basic visual searches. Generating a decent list does, however, involve retaining quite large numbers of specimens because there is always a dominant species and a tail of species that are far scarcer. The lists tell their own story, with good representation of species in Platycheirus, including many of those that one sees relatively infrequently further south (Table 2). One that I would single out is P. podagratus, which I think is a relatively early species and was probably on the wane when I arrived. My records mainly comprise females, so I suspect males were substantially over.

What is especially noticeable from the records is the relative lack of Syrphini, which are far more likely to be recorded as flower visitors and by active searching. Similarly, the Cheilosini were relatively poorly represented; I think for similar reasons.

Table 2. Species list for the trip, with numbers of records (record = occurrence of individual genders, so the actual numbers will be lower)
The final tally of coverage was relatively good, with 49 10km squares visited (Figure 1). Had conditions been better I would have expected the coverage to have been closer to 60 10km squares and a lot more records, but I made up for the lack of hoverflies by recording other taxa. There are a lot of fungus gnats and craneflies for identification by Peter Chandler and Alan Stubbs, and I have lots of sawflies, a few beetles and a scattering of other Diptera families to deal with. So, overall, the trip should have been reasonably productive. I will write more on other aspects of the trip in due course.

Figure 1. Coverage at 10km resolution

Monday, 22 May 2017

Feedback on noteworthy records

A thread posted on the NFBR Facebook group concerning noteworthy records provides food for thought. The important line is: 'You collect a species in a group with which you are not very familiar. Straight away you wonder - is it an interesting record? Would anyone be interested in hearing about it?' Responses to the thread frequently emphasised that all records are interesting, but of course the main point is whether the level of interest is enough to encourage an outsider to contribute?

The occasional record of something interesting may be an incentive to do more, but that really depends upon feedback. So, the critical issue is for Recording Schemes to make sure that contributors get regular general feedback, and individual feedback  either when they find something unusual or when the organism is fairly commonplace.

Feedback I have had from recorders suggests that they are discouraged when we, the specialists, don't put enough effort into giving the feedback that they want. The common complaint concerns iRecord where lots of posts do not get looked at because the scheme organiser(s) is/are not willing to participate or has/have not got the capacity to do verification on a daily basis. I am very guilty of that! If pictures are posted on Facebook pages, the common complaint is that nobody looks at them or, in my case, that I don't adequately spend time explaining why something is, or is not, what its contributor thinks it might be. One contributor took the trouble to express their frustrations (paraphrased) 'I put a lot of work into cropping these photographs and you could not be bothered to comment more than 'Syrphus sp.'.

We need to think about this. In the case of that particular contributor, I now try to write a bit more on each post. It adds to my time commitment, whilst not necessarily improving the numbers or quality of records entering the recording scheme!

The challenge we face is, therefore, how to provide the necessary feedback to enthuse potential new specialists, whilst avoiding burn-out amongst the existing specialists. I am afraid there is no simple answer. What we can say is that modern communication has raised expectations. Recording Schemes need to provide updated maps almost in 'real time'. We don't have the luxury of working for several years to produce an atlas – we really need that atlas to be on-line and regularly updated. Likewise, we need to engage on interactive media and make ourselves available to provide advice on a daily or even hourly basis.

These demands are a different paradigm to the days when a scheme organiser had the summer out in the field, spent the winter checking specimens and corresponded with those contributors that sent in record cards or sought help with identification of problem specimens. They were far gentler times. Today, organisers of schemes that generate large volumes of records must expect to spend several hours a day providing advice and verifying records. I don't notice a great rush of people who have the skills to do this and are willing to take on the job. I do see a gradual growth in skills and the development of a small cohort of people who will be able to take on aspects of mentoring that are essential. Mentoring is a skill in itself and we need to avoid pitfalls such as elitism or dogmatism.

This takes me to the nub of the problem. Where there are lots of capable specialists who are prepared to spend their time helping with ID and providing feedback, it may be possible to do more to provide the necessary encouragement. In many cases, however, there are very small numbers of people capable of providing technical advice and consequently the demand often outstrips the capacity to provide. Increasing interest in a group of organisms does not necessarily lead to a commensurate growth of specialists – that takes many years!

In the case of hoverflies there is no chance of providing a specialist County Recorder for all counties. I recall that when I tried to encourage one very capable recorder to take a more prominent role in the Hoverfly Recording Scheme the response was: 'I like the fieldwork but don't want to take on the administration'. Wise man! But we do need people who are willing (and able) to take on the administration.

Somehow we must cross this hurdle, but we must do so without sacrificing quality.

Sunday, 7 May 2017

It is worth reflecting on progress

Stuart Ball and I took on the Hoverfly Recording Scheme in 1991 and issued our first progress report in March 1992. At that time we had a huge pile of record cards to digitise and there were innumerable datasets to trawl and incorporate into a single entity. So, the first coverage maps comprised a small part of the data: around 100,000 records. The maps we published (Maps 1 & 2) showed the scale of the job to come. Not only were there around 2 cubic metres of record cards to digitise, but the records all had to be checked and erroneous elements resolved. As the early maps show, grid reference errors were commonplace (and still are!).
Maps 1 & 2. Map from the first newsletter in 1992 - overall coverage at 10 km resolution and the numbers of species per 10km square using a graduated scale.

 The most recent coverage maps that I have access to are for the middle of 2015. They provide a clear picture of the progress that has been made. At this point, the dataset comprised around 940,000 records, most grid reference errors had been resolved and the maps look pretty respectable (maps 3 and 4).

Maps 3 & 4. Overall coverage at 10km resolution and graduated scale for the numbers of species in 2015. The overall coverage map is graduated with clear circles and grey circles reflecting older records. Black spots represent the most recent records.

Both sets of maps provide important context for the achievements of the UK Hoverflies Facebook group in 2016. The final pair of maps show the coverage achieved from Facebook. iSpot and iRecord in 2016. These data and a substantial number of other datasets have yet to be completely incorporated into the database, so I cannot show precisely what was achieved in 2016. Nevertheless, these maps show some important achievements; not least how much new coverage has been achieved in south Wales (Maps 5 & 6).

Maps 5 & 6. Overall coverage and numbers of species recorded from Facebook, iSpot and Flickr in 2016
Each year there will be variation in coverage. New recorders will emerge and others will cease activity. Over time the maps will be filled in. So, I think we should look very positively on what was achieved in 2016. The maps for 2017 will be different, and when all of the 2016 data are incorporated I am sure we will see much more extensive coverage. The big challenge remains the need to recruit active recorders in the least well-covered areas.

Do we need a new approach to Hoverfly ID?

For a long while, I have felt that we are missing something with hoverfly ID in the UK, and especially in the case of live animal photography.

Stubbs and Falk has served us very well for over 30 years, but it comes from another era in which it was assumed that species identification would be based on specimens. Today, that is no longer the case, as photography has advanced and the numbers of people recording hoverflies has changed out of all expectations. The HRS was one of the first recording schemes to recognise the potential of photography and the Resident Team on the Facebook page have been active in this field for perhaps ten years. As such, we are pretty experienced. Nevertheless, we regularly encounter good photographs that we cannot take to species. Sometimes we are assisted by Gerard Pennards who we really ought to consider as a member of the team. Gerard brings a much-needed and valued European perspective.

This experience brings me to the nub of the challenge we face. Our current understanding of the UK fauna is based on a sub-sample of the European fauna. Although in places the keys do take account of possible European species, they don't tackle the fundamental problem of how to distinguish tricky photographs where you cannot change the angles to see critical characters. Sometimes we need to see a bit more, and sometimes, perhaps, there are perfectly good features that we don't recognise because our keys are geared to a restricted fauna. European keys often add in couplets to sort out overlaps that don't occur in the UK. This was brought home to me this weekend with a shot of a Parasyrphus that might either be P. mallinellus or P. lineola. The UK key simply concentrates on leg colour but van Veen makes a further separation based on antennal colour. That could be very useful when checking photographs. There are lots of other places where such splits might be helpful.

I therefore think we need to be working towards a new approach to identification of hoverflies in Britain. The current guides serve us well, but we might just do that little bit better and might find ways of improving the level of identification from photographs. That is not to say that we don't need taxonomy based on specimens; clearly there are many places where we cannot avoid the need for specimens. BUT, I think we might just enter a new paradigm if we start to tackle the question of ID from a live animal and photographic perspective.

All I need now is the time to think out the approach! I think it is the sort of thing that could be a really nice opportunity for collaboration between UK and European specialists. There is no doubt the UK would learn a great deal from our European counterparts, but we would also bring important experience to the table.

Tuesday, 2 May 2017

Data verification - how is it done?

A question posed on the NFBR Facebook group today raised an interesting question ' Do BWARS, or any other recording scheme or BRC, publish any guidance on verification for their species group?'

I have never tackled this problem directly but have given some guidance to novices about self-verification after making an identification. Once you have made your diagnosis, it is important to check some basic data:
  • Does the animal conform to the detailed descriptions given in major monographs such as Stubbs & Falk or Van Veen.
  • Does the species occur in your general vicinity? It may not have been previously recorded from your 10km square but if you live in NW Scotland and the determination you have made is of a species that is confined to southern England, you can be pretty sure your ID is either wrong or the record is highly aberrant. Range is important!
  • Does the date recorded coincide with the core phenology range? If not, there must be doubt, although there are exceptions.
  • Is the species common or rare? Bear in mind that rarity does not mean that you won't find such an animal, but the vast majority of records are of common species, and many rare species have peculiar habitat associations. If the species is rare, make extra checks and seek the view of a specialist.
  • Can a firm identification be made using the medium you have chosen? If you are basing ID on photographs, you need to be aware that a lot of hoverflies can only be identified with certainty using microscopic characters that either don't show in photos or are on a part of the animal that cannot be accessed using conventional live-animal techniques (e.g. the male genitalia).
  •  Are there other species with which it might be confused?
  • Does the habitat match the descriptions in the guide book?

So, how do I verify records?

If a record is accompanied by a photograph I can start by saying:
  •  Is the animal sufficiently well depicted to make an ID? We do see a fair selection of photos that are at low resolution and cannot be used to look at key features; many photos are also from angles that don't capture the critical features, and some are obscured by glare and colour casts that give rise to uncertainty.
  •  If it is potentially identifiable, can I conclude the genus? if so:
  • Can I take this animal to the correct couplet in the key? if so:
  • Can I arrive at a firm conclusion either at specific level or for a species pair (e.g. Platycheirus scutatus sl. or s.s.)
  • If the affirmative can be given for the above then I can either verify the diagnosis made by the recorder or make my own diagnosis.
Where records are not accompanied by a photograph (or supported by a specimen) I follow a pretty standard routine:
  • Is the recorder and their abilities known to me? If so, how experienced are they? For experienced recorders that are a known quantity I probably don't need to do much for common and readily identified species. If not, it is helpful to see a full list of their records to get perspective of what they are recording. Each time I see a dataset I build a picture of the competency of the recorder.
  • Do the records coincide with the known distribution and phenology for the relevant species? If on the limits of these ranges then one might want to check further.
  • If a single record then obviously one cannot do much more than say 'is this record potentially believable? In many cases one has to use a significant element of trust. To my mind this is not really verification it is just a broad-scale quality assurance process but in no way says that all records are correct. We all make mistakes, so all datasets are likely to contain glitches. For the most part, a low level of mistakes has little or no impact on the reliability of the data.
  • Are there tricky species? If so, I may go back and ascertain the presence of a specimen. If there is no specimen and the recorder has relatively low levels of experience then the record may not be reliable. An awful lot of verification is based on trust and a knowledge of individual recorders, so that is something that only happens over time.
  • And, in knowing recorders I often ask myself how bold they are in their diagnosis - the more caution I see, the greater assurance I have that records are likely to be reliable if not perfect.

So what about verification of iRecord?

I get frustrated with iRecord and much prefer spreadsheets. My reasons are focussed on data that are not supported by specimens or photographs. Analysing a spreadsheet is a relatively quick process, whereas trying to sort out the odd few records entered intermittently on iRecord involves a lack of context.

When I receive a spreadsheet I quickly scan for certain indicators. For example, if I know that a recorder does not take specimens and their lists contain species that cannot be done from photos or in the field, then the data is suspect. Does the list contain 'Chinnery' mistakes? There are glitches in Chinnery that are giveaways that the data are suspect - I won't give these tricks out because they are so useful to me! Are there records of females that can only be taken to aggregate but are listed as a segregate?

Similarly, do the lists contain habitat indicator species that are clearly out of range. A classic is to see inland dry sites with lists that include species such as Platycheirus immarginatus (it does happen and shows that the data have been created using the pictures in Stubbs & Falk).

There is no guaranteed way of ensuring correct identifications and with lists it is a matter of trust. Having spent a lot of time developing data from photographic photographs, I now have a big dataset that has improved the parameters for species phenology. I also know a lot more about the potential problems that people encounter - the list of mistakes is huge, as my previous post on iRecord data has shown.

And, there is a lesson for us all

On one occasion I accepted a record that was not supported by a photograph but came from the right sort of place and was not terribly difficult to ID, so I accepted it. Shortly afterwards, the originator posted a photo of the animal and extolled the virtues of iRecord as a means of confirming the identity of a specimen. The photo and the determination did not match - this made me look a fool! It just goes to show that unless the verifier checks a piece of chitin on a pin, the record can only be said to be likely to be reliable and not a correct ID!