The future direction of the Hoverfly Recording Scheme?

The HRS was established in 1976, at a time when we knew a great deal less about simple issues such as distribution. Recorders were reliant upon the RES key by Coe, which was a classic lesson in how to make identification difficult (a key by a specialist for specialists with access to museum collections). The complexity of the key meant that there were very few recorders and most Dipterists regarded hoverflies as 'too difficult'. Early on, many species that we now regard as quite 'run of the mill' were thought to be scarce and special. The development of two generations of guide books has changed perceptions (and reality) so that hoverflies are now a mainstream interest for many field naturalists - it is an amazing paradigm shift.

In a way, that lovely innocence of 1976 has been lost. The low-hanging fruits have been picked and the excitement of new discoveries now comes after much more effort. Modern maps tell us a great deal about species' current distribution and, apart from filling in a empty gaps, mapping at a Great Britain level alone is unlikely to provide the stimulus for recording that it once did. There is plenty still to do at a local level, with a good many under-recorded areas of Great Britain. Unlike other popular groups such as butterflies, moths and dragonflies, the numbers of recorders are still comparatively small and there is still scope for developing local groups and for local mapping projects to emerge (a challenge or opportunity whichever way you look at it).

With the basic task of mapping substantially established, what sort of niche should the HRS fill? Clearly, climate change and changes in countryside management mean that we still need to continue the basic recording so that changes in distribution can be detected. There are quite a few species marching northwards. The most obvious ones are Rhingia rostrata, Volucella zonaria and V. inanis, but others such as Epistrophe diaphana are quietly pushing boundaries too. Some northward expansion may be subtle but detectable over several decades. At the same time there are a few species spreading southwards: Callicera rufa, Sphegina sibirica and Xylota jakutorum immediately spring to mind. These seem most likely to be a late stage response to coniferisation and to the felling cycle. What about declines or contractions in range? These are MUCH harder to detect so we continue to need to generate the best dataset possible.

Understanding trends

Modern data management and statistical modelling have enabled researchers to look at recording scheme data in ways that could only be dreamed of ten years ago. Stuart Ball started to look at HRS data in this sort of detail a bit more than a decade ago when he and I published an analysis of the distribution of Volucella zonaria. He also did some similar work on coincidence analysis back in the 1990s and was a key pioneer in this approach, doing some great work on climate change predictions and occupancy modelling. More recently, modellers at CEH have taken up the challenge and various groups are now using HRS and other data to investigate animal and plant distribution and trends. Their work is taking the ideas forward and demonstrates just how important it is to maintain and grow biological recording across the country. So much more can now be achieved with 'ad hoc' data.

Although the dataset of the HRS (and other schemes) is somewhat 'ad hoc', there are elements within it that are more structured. This structuring of data collection is something that I believe we need to pursue. Butterfly and dragonfly recording have the transect approach. Moth recording has the Rothampstead trap programme (and garden moth scheme). I think hoverflies also need something. Alan Stubbs proposed a garden monitoring scheme back in 1991 and various approaches have been trialled in recent years. Those trials have not been frightfully successful because of the vagaries of weather and low numbers of people involved. However, we are now seeing a significant growth in people who make a daily record of what they see in their garden or local nature reserve. This sort of daily recording is really very valuable and analogous to the garden monitoring scheme so I have great hopes for the future.

The big issue I think is not only to grow the data flow, but also to improve feedback to contributors. If people can see that their efforts are both valued and used, they will hopefully be stimulated to continue.

Feedback on yearly and longer trends is an obvious progression for the scheme, and is something that we are already doing to some degree. I think we need to take it further, and I know that Stuart has this in mind in the design of the new HRS website. We should soon be able to provide on-line access to such analyses. That will be a major step forward.

Making links to biology

The other crucial stage in the process is trying to make sense of what trends tell us. For that, we really need a much better understanding of hoverfly ecology and larval biology. That is where we have needed to make advances within the scheme. A great deal of work was done by Graham Rotheray and the Malloch Society. They have been the pace-setters for hoverfly ecology. More recently Graham's daughter Ellie has started to engage with a much wider constituency and, together with Geoff Wilkinson, has really got things moving with the UK Hoverfly Larvae Facebook page. That is a great advance that I think needs to start to be the nucleus of the way forward into a more holistic approach. There is plenty more to do, as the morphology and biology of about 60-70% of the British hoverfly larvae is known to some degree. Investigating larvae is something that can be pursued by lots of people if they have the inclination. You don't have to be an academic with lab facilities - basic field skills, tenacity and inquisitiveness are the most relevant skills.

Live animal taxonomy

Most keys were developed using preserved specimens. They are subtly different to living animals and until very recently live animal taxonomy was very tricky. Modern digital photography has revolutionised the imaging process (especially with stacking techniques) but identification of living animals has lagged behind. Many experienced specialists can discriminate between species in the field but actually explaining why two species differ is often a great deal harder to put into a structured approach to identification.

We need to develop is aspect of identification – something that a relatively small group of people have started to develop, with Ian Andrews and Joan Childs taking on the bulk of this challenge. Should we be creating better links with overseas specialists to try to develop a pan-European network of specialists working on new ways of describing how to identify live animals? The WILDGuide that Stuart and I wrote is a first stage in the process, but I am the first to admit that my approach would be a bit different today after experience of the last five years dealing with photographic records. That is not to say that I find fault with the WILDGuide - it is simply that with many more years practical experience of what people see and how they record, I think we might present some elements differently and focus on slightly different issues. Maybe this is something beyond what can be done by the HRS but it points to a direction that we might want to go.

Organisation for the future

When Stuart and I took on the HRS in 1991 it was really focused on dot maps. I'd like to think that we have taken it several stages beyond those early objectives and that the sorts of outputs that happen today are a logical progression from basic mapping. I think we probably have a little way to go before the scheme is seen as anything more than a mapping and data assembly project, but progress has been made. The next step is to embed those wider principles of data assembly AND analysis. For this, I think we will have to start to broaden the team further, so we have greater analytical depth. It is probably too soon to actually recruit further analysts – I am hopeful that in time Ellie will develop part of this portfolio, but we will doubtless need others. I have my eyes open for potential recruits!

The next important step is to develop a more secure data management structure. I have taken this as far as I realistically can, and am jolly pleased that Geoff Wilkinson has joined in and is tackling the data from the larval group. I hope that by Christmas Geoff and I will have developed a new protocol and system that allows a broader group of people to do the data extraction.

The bigger question is whether we should be actively promoting the development of local groups? My instincts are that there are probably too few people who might act as local 'shakers and movers' for there to be a significant network, but I do see potential for some growing nodes of activity, possibly as local Diptera groups rather than simply for hoverflies. This sort of local organisation is the place where I think we might look to recent graduates who want to establish credentials as potential shakers and movers for the future. I have previously said that I would like to gradually reduce my involvement so that there is a seamless transition from the 'old guard' to a new an vibrant generation. Geoff and Ellie are obvious successors, but I suspect we will need a much bigger team because there is so much more to be done than in the simple days of record cards and the microscope!

In setting out these thoughts, it is my intention to put down a marker that I have recognised a need to evolve the structure of the HRS in order to give it the resilience to survive beyond the Ball & Morris partnership. We need to be gradually taking more of a back seat so that new blood takes over and gives the scheme the impetus for a further generation.

Data for data's sake

Aaron M. Ellison's article in Nature (11 October) gave considerable food for thought. It got me thinking about the issue of data and what we use it for. Is there a tendency for researchers to call for more and better data even though the real power of data may not be at the level of minutiae? It is much the same as the usual caveats about monitoring after a development project.

I have seen far too many cases where there has been a 'monitoring' package that is far too woolly and unfocussed to generate any real enlightenment about the impact (or otherwise) of a particular project. In development cases, what is proposed is often more closely aligned to what the developer is willing/able to pay for and not what is needed to pick up causal links. I concluded a long while ago that much of this monitoring was of very limited value and that conservationists rarely kept much of an eye on its outputs. In my experience, an agreement is made, the development takes place and a lot of expensive 'monitoring' is carried out. The resulting reports are rarely scrutinised by anybody in sufficient detail to determine whether they have actually served their purpose, and any critical lessons are rarely, if ever, learned.

As an example, I will use the monitoring for South Humber Bank Power Station back in the mid-1990s. ERM did an excellent piece of work that clearly showed that shorebirds were not affected by pile-driving – they habituated very rapidly. This same piece of work drew attention the the daft anomaly whereby a developer was expected to put in place millions of pounds of measures to protect birds from noise and human disturbance, whilst those same birds were constantly disturbed by dog walkers (and dogs), fishermen (beachcasting) and even by birders. The list of 'other' disturbances was shocking.

I certainly drew a lot of conclusions from this and regularly cited the report. I also marked it as a critical report when I left EN's Wakefield office. Two years later I wanted access to the report but the local team could not locate it. I went back to Wakefield to look for it and found it: when I left, I had carefully laid out all the the critical documentation with carefully compiled notes so that my successor had an idea of what mattered. The following day the they had simply piled all the documents up, put them in boxes and dumped them in a corner of a store cupboard. Nobody knew a thing and that explained why I was regularly rung up with queries. What a waste of three weekends on my part – I should not have bothered!

Do we need more data?

In the early days of English Nature many of us were shocked by the message from above that we had sufficient data and that there was no need to collect any more! That saw the demise of survey teams such as the 'England Field Unit'. In fairness, we were in a very difficult financial state but that does not justify the statement that we don't need new data. Subsequent events have shown that there is an ongoing need for new and better data, but that it must be collected and USED, rather than simply collected to sit in unread and forgotten reports.

That brings me on to what sort of data should we collect? In terms of biological recording, data on all taxa are needed. BUT, I would argue that there is a crying need for better data on more obscure taxa and, more particularly, people who actually understand what they mean. Thus, those who wish to pursue a career in conservation I think the critical issue is to be both a user and a contributor of data. That means developing field skills and then pursuing a course of investigation that takes you beyond the comfort zone of popular groups. If we don't see a significant expansion in skills in less popular taxa they will always be Cinderella subjects and will not gain traction when used to justify the case for conservation.

Yearly phenology signatures

A couple of days ago, I investigated the overall yearly data 'signatures' generated by records from photographers. I only went back over 3 years because it was not until 2014 that activity was sufficiently strong in the early and later parts of the year to present a comprehensive picture of hoverfly activity.  Prior to this, most of the data collected was opportunistic - gathered from various web sources such as iSpot and Flickr and the late-lamented Wild About Britain.

The emergence of the UK Hoverflies Facebook group has triggered much more detailed recording. There is now a group of 20-30 people who record on an almost daily basis. This sort of recording makes it possible to look at hoverfly abundance in a completely different way.

I took as a starting point the raw data for each day, plotted as a simple chart with a 30-day centred running mean superimposed. This approach has the obvious drawback that the dataset is bigger than the last one in each successive year (Figure 1). A second stage was needed to smooth out year on year differences in data volume - which I dealt with by turning daily plots into a proportion of the total records for that year. In this second stage I have simply presented the 30-day centred sunning mean (Figure 2).

So, what does this tell us?

In both 2014 and 2015 there was a steep rise in spring hoverfly activity that peaked in April before dropping off into May. This pattern looks to be consistent with recent years when a cold snap in late April and May has badly affected insect activity. In 2016 this pattern was not as obvious: activity started much earlier in the year, indeed it barely stopped at all throughout the winter. Numbers rose rather more gradually and the first signs of a stutter were in mid-May.

The peaks for hoverfly activity seem to have been in mid- to late-July in both 2014 and 2015, whereas there were two peaks in 2016. The first was in late June. A brief spell of fiercely hot weather in July clearly suppressed hoverfly numbers and many FB members commented on the apparent absence of hoverflies all over the country. A second peak followed in September, which was one of the warmest in several decades.

The autumn fall in hoverfly abundance also differs: in 2014 it was fairly precipitous and by the end of October there were very few incoming records. 2015 was far warmer and the decline was much more gradual.

The 3 year signatures also show how in 2015 and 2016 the season of high hoverfly activity was much broader, illustrating the effects of the warm winter of 2015-2016. Obviously it is too soon to comment in any detail about the Autumn of 2016 but the numbers of incoming records are still high.

Figure 1. Daily records of hoverflies based on the photographic dataset with a 30-day centred running mean

Figure 2. 30-day centred running mean of records presented as a % of the yearly totals

Brexit and its significance for wildlife

As we start to get used to the idea that 'Brexit means Brexit' an important question for those with environmental concerns must be 'what will be the impact of Brexit?'

During the referendum campaign some very dubious promises were made by the Brexiteers. £350m per day would be repatriated and spent on the NHS and all sorts of pet projects such as scrapping VAT on energy. Well, the Brexiteers have Teresa May's feet in the fire so she will have to deliver some of these wild promises or else she will be booted out of office!

Where will the savings come from? You can bet your last GB Pound that environmental and science budgets will be at the bottom of the wish list so hang on to your hats as we see a massive change in land use. We must anticipate huge declines in wider countryside wildlife as the farming world tackles the challenge of working in world markets without subsidies. or, perhaps more likely, that agricultural subsidies will focus on giving UK agriculture leverage in world markets. Either way, we must work on the assumption that there will be little or no money for wildlife and it will be the natural environment that takes one of the biggest hits.

We cannot do much about the political decisions that lead to the loss of wildlife but we can do something to chart the effects of Brexit on Wildlife. That means that we MUST make sure that the changeover period is well-documented. So, anybody who cares about wildlife needs to start to properly record what they see. If we have an army of recorders whose combined data are there to tell a story, then we can at least show the environmental cost of Brexit and thus the need for new action.

This post is therefore a rallying cry to field naturalists to sharpen your pencils, get the specimen tubes and cameras ready and make sure that the data for the next ten years is as comprehensive as possible. Wildlife needs you more than ever - please don't let the natural environment down!

Why record common species?

We heard on the radio today that the 'Common Toad' was in serious trouble. Sadly, its name suggests that it is still common, and yet the evidence points in quite a different direction. My experience in Mitcham strongly points that way. When my team surveyed the common in 1984 we did regular assessments of the breeding population of both frogs and toads. There were literally thousands of toads that spring. Sadly, a major fire some 500 metres from the main breeding pond killed a substantial part of the toad population that autumn. Crows had a magnificent feast for a long while afterwards!

Toads continued to breed in the ponds for several years but numbers declined; both within the main pond whose population had been catastrophically damaged, and elsewhere. Regrettably, nobody did regular counts in subsequent years so the impact of the fire is difficult to assess. Was this event the start of the decline or did something else happen? I cannot help feeling that the introduction of common carp and the destruction of weed beds in the ponds played an important part in the Toad's decline, but maybe there were other factors too?

The loss of such a thriving population is a tragedy but it has wider implications. I recall that in the late 1970s and early 1980s I occasionally happened across dead toads with infestations of the Calliphorid Lucilia bufonivora. That too is regarded as 'common' but I rather suspect that is no longer the case (NBN data seem to indicate a contraction but I cannot be sure). Had we had the levels of biological recording that we have today back in the 1970s, perhaps we could say a lot more about the decline of the 'Common Toad' and what has happened to Lucilia bufonivora.

This sorry tale has numerous parallels, such as the demise of the Passenger Pigeon - a once abundant bird in North America that is now extinct!

So, moving on to today's world in which there is increasing capacity to maintain all records, why don't we record common species more consistently? Only this morning a a major contributor to the Hoverfly Recording Scheme commented to me that he was unsure how much I would value repeated records of commoner hoverflies. My answer - to the contrary, we are keen to get good date runs of records. This is one reason why I now make an effort to log everything I see when out on my daily walk. Daily fluctuations are an important body of information that can be stored quite easily but cannot be reconstructed once the time has passed. We just don't know what our data might be used for in the future so the wise course is to log what one sees.

In a broader context, Brexit poses quite a serious risk to our wildlife. We really need to be on top of the issue and able to detect any changes that result from the loss of agri-environment schemes and intensification of farming practices. Making sure we record common species is an important first step - if we don't record common species we may not pick up problems in the countryside until the effects are extreme and even more difficult to reverse.

Composition of the photographic dataset of hoverfly records

A recent thread on the NFBR Facebook page drew attention to a piece of work looking at the differences between identification by 'experts' and various (relative) novice recorders. This paper generated a range of comments and stimulated me to reflect on the advent of photographic recording. I took the view that the glass is definitely half full and probably a good deal more full than the most sceptical specialists might think!

I have written previously on the importance of modern media as a way of bringing 'new blood' into biological recording and the need to embrace this new paradigm. The Hoverfly Recording Scheme has done so for many years and I think the dividends are there for all to see: we have seen a massive increase in recorder effort but have also started to recognise that this sort of effort is unsustainable without a fundamental change in the way recording schemes are organised, taxonomic guides are written and perhaps even in the way taxonomists work to describe species.

Live animal taxonomy is a challenge, and probably cannot be taken to the refinement that is possible with preserved specimens and modern molecular analysis. BUT, it is likely to be the major source of data in the future and we really need to understand its implications for data analysis and for conversion of these analyses into land management policies. This paradigm shift has been the driving influence behind my interest in photographic recording and trying to understand and quantify what is possible.

After at least eight years of data extraction from photographs, I think we are in a strong position to analyse the potential of photographic recording for hoverflies. The sheer scale of the data arriving is obvious (figure 1), but what does it really mean in terms of the spread of species recorded? Furthermore, are the numbers of records translated into something useful for land management policy? More analysis is needed to come to any firm conclusions but the data do suggest that at least for hoverflies there is potential to use photographic recording for certain analyses. The spread of species is substantial (over 150 species in 2016) and, as can be seen from Figure 2, the tail of irregularly reported species is long. At the moment I am far from clear how this compares with traditional data and will have to access the full dataset to gather a better understanding of this relationship.

Figure 1. Monthly records of hoverflies based solely on photographs extracted from Flickr, iSpot and Facebook

The spread of species is substantial (over 150 species in 2016) and, as can be seen from Figure 2, the tail of irregularly reported species is long. At the moment I am far from clear how this compares with traditional data and will have to access the full dataset to gather a better understanding of this relationship.

Figure 2. Composition of the 2016 dataset (23,790 records)

 Figure 3 (below) also illustrates how the dataset is dominated by an ever-shifting range of species throughout the year, with some obvious surprises amongst the listings of the top 20 species for each month. There must be a health warning, however, as data from traditional sources who retain specimens have yet to be analysed. My past experience has found that there are substantial differences and that one has to be clear about the source of data before drawing any conclusions about species abundance and distribution.

Figure 3. The 20 most frequently reported species each month in 2016 organised in rank order for each month.

More analysis will be provided in due course, but I hope that these three figures alone will act as a stimulus to other recording schemes to engage with photographic recorders. There is plenty of good will out there and lots of potential for growing our knowledge of Britain's wildlife. My one word of caution is that the level of interest can be overwhelming and consequently we need to change the way in which recording schemes are run. In future we will have to look far more towards a team effort rather than one or two people working on their own. That means that over time some of the contributors must be given the opportunity to play a more active role in data management and mentoring; something that the Hoverfly Recording Scheme is currently working to address.