Sunday, 16 October 2016

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.

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