Monday, 29 October 2012

Photographic records - some further analysis

As the winter races towards us the numbers of hoverfly photographs being posted on the web has greatly reduced. In mid summer I can spend as much as two hours a day extracting data. Today it took me ten minutes! And, for my troubles there were no new hovers but a couple of other fly families. I shall hopefully write the exercise up in detail for a peer-reviewed journal later this winter, but it is worth sharing ideas at a much earlier stage.

The number of records secured from websites and occasional records sent as photos by e-mail has just passed 10,000 and the number for 2012 has exceeded 3,000. The graph (Figure 1) tells an amazing story of how photo-recording has taken off. The rate of change is phenomenal, but what it does not show is the numbers of records that later come in from people who now maintain a separate record of what they see and send me a spreadsheet.  There are several people who now do this, so I don't need to extract their photo-data. Thus, there is a gradual transition from photo recorder to active recording scheme contributor. At least five people have made this transition and they now contribute significant numbers of records each year.
Figure 1. Numbers of records gathered from photographic websites over the period to October 29 2012.

Gaining a new active recorder is a great boost to the scheme and this can be exceptionally valuable when they make a note of everything they see. So much more can be done with big datasets and it is the relatively widespread or abundant species that are often useful for analysis of issues such as responses to climate change. Of course there are exceptions as I have previously shown with Volucella, but species such as Epistrophe eligans, Leucozona lucorum and Rhingia campestris all tell important stories about responses to environmental variables. That reminds me that Stuart and I really need to write up some of these formally!

As I highlighted the other day, photo recorders can occasionally turn up exceptionally important records and so I am keen to encourage new participants.  That is not to say that everything can be identified, but even if a confirmed ID cannot be given, the hint of a rare species' presence may be sufficient to get somebody to take a closer look at an area.

It is quite staggering just how many people do take photographs of wildlife and put them on the Web. ISpot has been exceptionally successful, but I find Flickr a very useful source too. My great regret is that around 50% of photos still have no details of where and when they were seen. So, if you take photos and place them on Flickr do put some data with them. Geotagging is great as I can usually find a 6-figure grid reference from this but even the name of the place is often enough to get a ten kilometre or one kilometre grid reference.

Figure 2. Numbers of recorders and the numbers of phot-records. One person has generated 1000+ records and one just over two hundred.
Relatively few people regularly photograph hoverflies as can be seen from Figure 2. But a few are amazingly prolific. I'm always delighted when I find a new active photographer but these days that is quite rare because I have spent so much time syrphing the net this year.

This graph shows how a relatively small minority regularly photograph hoverflies but that minority has made a very substantial contribution to the overall dataset. This is little different from the main data reaching the Recording Scheme where just 21 people contributed 50% of the data that was used in the last atlas.

No comments:

Post a Comment