A new paradigm in biological recording? Monitoring hoverflies with digital photographs Roger Morris Hoverfly Recording Scheme www.hoverfly.co.uk With photographs by John Bridges http://northeastwildlife.co.uk/
What is a hoverfly? • Order: Diptera (Di – two; ptera – wings) – the second pair of wings is modified to form the ‘halteres’ – turn and bank indicators. • Family: Syrphidae
What makes it a hoverfly? Photo Stuart Ball
The UK Hoverfly fauna • 283 species (2 confined to Ireland) • Adults are recognised as important pollinators of flowers, but also • Wide range of larval biology, including: • aquatic filter feeders; • saprophages, including dung, fungi and decaying wood; • leaf, stem, root and bulb feeders; • predaceous upon aphids and other larvae; and • associated with nests of bumblebees, Myathropa florea social wasps and ants.
Foundations of biological recording • Victoria County Histories – accounts of species known from many (all?) counties. • Journals of Natural History Societies and some specialist journals. • County atlases – predominantly botanical and birds. • National atlas schemes – with the bar set by Perring and Walters (Atlas of the British Flora – 1962).
Hoverfly Recording Scheme • Established 1976 • 1976-1987 two scheme organisers – John Ismay, followed by Philip Entwistle. No scheme organiser from 1997 to 1991 when Stuart Ball & Roger Morris took it on. • Atlases published in 2000 & 2011 and another due out soon! Chrysotoxum arcuatum
Traditional administration of recording • Largely voluntary using a network of non- vocational specialists. • Central co-ordination and publication by the Biological Records Centre (formerly Monks Wood and latterly at CEH, Wallingford). • Local records centres – variable in manpower and who runs them.
Traditional data capture • Traditionally – paper based – using record cards or conventional letters/publication. • Relied on one or more Recording Scheme Organiser to interface with the contributors. • Data digitised centrally at Monks Wood. • Not all taxonomic groups had (have) a recording scheme – dependent upon there being a willing and interested specialist.
And then came easy access to powerful computers! • Database technology. • Electronic data transfer. • Shift away from paper-based technology and towards RS organisers managing the scheme’s data. • The first paradigm shift!
Data submitted by traditional routes
And then: Digital photography • Jepson, P. (2005) ‘Natural History Re - mastered’. British Wildlife , 17(1): 27-31. • Suggested that Digital photography would replace traditional recording and the need to retain preserved specimens. • A second paradigm shift?
New data capture systems • Web-based facilities to upload photographs. • Crowd-sourced identification (WAB, iSpot). • Potential for interactions with a different cohort of biological recorders: • Casual observers with a camera. • Photographers who want their subject matter named. • Keen recorders who branch into new disciplines but do not want to retain specimens. • Those who want to make a contribution to the state of knowledge about wildlife but lack the experience to tackle difficult taxa.
Recording hoverflies from photographs • Started around 2007 but became a major activity of the HRS by 2009. • Data extraction entirely by RKAM (at the moment) from: • iSpot • Wild About Britain • Flickr • Ipernity • Picassa • Other blogs and websites
Basic progress
Yearly data growth
Relative contributions of data sources (Log 2 )
Scale of individual photographic contributions
Contributors to data sources
Key messages • There are substantial numbers of people who take at least a passing interest in hoverflies as a photographic subject. • Data from such sources have grown in response to new data capture systems. • The establishment of the Facebook site and ‘community’ has played a big part in fostering interest and participation.
But ... • Crowd sourced identification still relies upon a small number of specialists. • The UK Hoverflies FB Group relies upon 3 ‘resident specialists’ who have many years experience using microscopes and keys. • Data extraction takes up nearly all of the time of one specialist from May to September. There is no additional specialist capacity!
Lots of data but is it any use? • Critical review yielded the following comments: • ‘Outrageous’ and ‘grossly misleading’ to suggest that so many species can be identified from photographs. • ‘Only about 30 species can be reliably identified from photographs’. • ‘It is a waste of time extracting data for a few common and easily identified species’. • ‘very little scientific value in this paper’.
Let us test the validity of these assertions • Records so far of more than 150 species, including several rarities (e.g. Callicera aurata , Callicera spinolae , Eristalis similis , Meligramma guttatum , Meligramma euchromum , Pelecocera tricincta ). Critical identifications often checked with Meligramma guttatum European specialists.
Is it worth collecting data for ‘common’ species? • Trend analysis calls for large volumes of robust data. • Records of rare species will always be sparse. • Commoner species are therefore often the most useful bellwethers of change. Episyrphus balteatus
Is rarity always what it seems? • Some species are there but occur at times when recording is difficult (e.g. Spring) – need more recorders. • Species’ abundance can change – what is rare now may not be in 20 years time – need lookouts to spot the change. Cheilosia grossa – photographic data
Dominant species • ~ 35 species make up 90% of the dataset. • Poor coverage of difficult genera – Cheilosia, Pipizini, Platycheirus and Sphaerophoria. • But good coverage of many species that have responded to climate Helophilus pendulus change.
Uneven recording Tribe GB Fauna Species % GB fauna Identified Unidentified Total % recorded in sample records records records Identified Volucellini 5 5 100 886 5 891 99.4 Xylotini 20 14 70 647 11 658 98.3 Eristalini 28 19 67.9 3488 380 3868 90.2 Callicerini 3 2 66 4 0 4 100 Syrphini 84 45 53.6 3352 1031 4378 76.6 Bacchini 30 15 50 860 291 1158 74.3 Cheilosini 43 17 39.5 634 170 804 78.9 Chrysogastrini 29 10 34.5 108 49 157 68.8 Merodontini 7 2 28.6 188 15 203 92.6 Microdontinae 4 1 25 1 0 1 100 Pipizini 20 3 15 9 63 72 12.5 Paragini 4 0 0 0 4 0 0 Pelecocerini 3 0 0 0 0 0 0
Lessons • It is a misconception to think that photographers will only encounter ‘common’ species. • Increased recorder effort will change perceptions of ‘rarity’. • But, there are limits to what can be achieved from photography. • A significant proportion of the fauna is either not encountered or unidentifiable from photographs. • The positive message is that a bigger recorder base can be grown from photographic recorders.
Use of biological records • Mapping – traditional atlases BUT – so much more: • Red lists • Site-based conservation • Climate change indicators • Phenological change • Aspects of species’ biology • Pollinator ecology?
So, what sort of data are required? • High resolution • Reliable • Verifiable • Repeatable
Outcomes 1 - coverage 2014 Photographic 2014 data species per HRS species per Photographic hectad hectad coverage
Outcomes 2 • Good yearly data-sets for 2013 about 40 species, which can be used to investigate 2014 phenological change or differences. Phenology of Episyrphus balteatus in 2013 and 2014
Outcomes 3 Phenology of Epistrophe eligans in 2014 • With sufficient records it is possible to detect North change both within and between years. • Needs lots of recorders across the country and for Midlands those recorders to be active at critical times. • Photographers are different because they South will look for all sorts of subject matter.
Outcomes 4 • Investigating autumn and winter hoverfly activity. • There is a lot more going on than we knew hitherto!
Potential of new working • Think of a photo as a voucher specimen – it conveys important data: • Gender • Numbers • Activity record – flower visits, predation, oviposition. • All data need to be extracted but many recorders don’t do this when entering data onto iRecord.
If you have the data you can do so much more! Volucella zonaria Male Volucella zonaria Female
And even change people’s lives! • Create a virtual community with people that know one another electronically. • New interests for photographers – at least two have commented that this new interest has greatly brightened their lives. • Need to recognise this paradigm as a challenge for traditional societies – not a threat but a new opportunity.
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