Cost-effective environmental imaging services combining camera drone and cloud technology
As a drone pilot and operator registered with CAA in the UK I’m able to offer a variety of commercial services in open countryside locations, where a full PfCO is not required.
On one privately owned site in the Surrey Hills AONB I mapped 32 hectares (79 acres) of part ancient, mixed broadleaf woodland.
Thousands of individual images were stitched together to create an orthomosaic which was then exported as individual GeoTIFF tiles capable of being displayed in GIS software, and also as ultra high resolution single images.
Mapping missions were flown at different times of year to show seasonal variation.
Using spectral analysis techniques it’s possible to use aerial imagery for environmental monitoring at landscape scale. The image below compares visual spectrum vs. enhanced NDVI processing to study plant health.
Orthomosaic images can also be used to make accurate measurements to inform effective land management. The aerial map below quickly measured the extent of a heathland fire at Thursley Common NNR for Natural England.
In addition to orthomosaic still images I also produce aerial video footage showcasing natural landscapes.
By layering orthomosaic images created in different seasons it’s possible to create a wide area timelapse sequence, as shown below.
The animated video above shows ancient woodland in West Sussex photographed over the course of one year. It is prime habitat for the White Admiral butterfly.
More conventionally, the video below shows scenes from a Bluebell wood in early spring. Bluebells are an attractive ancient woodland indicator species.
In Sussex during the COVID-19 epidemic of 2020 I followed one very special butterfly through pupation to emergence
The White Admiral (Limenitis camilla) is a large woodland butterfly which glides effortlessly along forest rides. Its numbers in the UK have rebounded since the First World War, possibly due to the cessation of coppicing which, unusually, has benefited this species since its larvae require Honeysuckle growing in shady woodland.
My first, long awaited, encounter with ‘Camilla’ came on 28 May when my many searches of Honeysuckle vines finally bore fruit and this magnificent creature suddenly greeted me.
White Admiral caterpillars are entirely dependent on Honeysuckle for their survival, feeding on its leaves through all five larval instars and hibernating within their folds.
At more than 2 cm in length this was a fifth and final stage caterpillar, exotic in appearance compared to the majority of British butterfly larvae, adorned with branching red spines along its back and resting in a raised serpentine position.
When I returned 3 days later Camilla was already preparing to pupate, hanging beneath a Honeysuckle leaf, suspended from her hind claspers attached to a pad of silk.
48 hours later the pupa was now fully formed, with two prominent horns on the head and an odd protrusion further back.
“The pupa bears a close resemblance to a profile portrait of Punch.”
– Frohawk (1924)
The pupa darkened up a little in the next few days, its undulations mimicking the Honeysuckle leaves quite convincingly.
For the next two weeks few visible changes occurred and the weather turned cold and wet. A marauding army of small birds came and went, leaving Camilla thankfully undisturbed.
Around Day 22 the folded wing veins became a bit more pronounced beneath the pupal case and its body seemed to have plumped up a bit. Warm, sunny weather had returned to the woodland glade.
Revisiting on the morning of Day 23 I found Camilla had darkened up overnight, turning from green to brown, signalling that ‘eclosion’ of the adult butterfly was imminent.
By 5pm that afternoon my ‘White’ Admiral was now distinctly black!
From a different angle the butterfly’s wing structure and patternation could clearly be seen.
“Before emergence it turns to a bronze-black all over, losing almost all the metallic lustre of silver-gilt; the white wing markings of the imago show pale amber colour through the pupal skin.”
– Frohawk (1924)
I was hopeful the adult butterfly would emerge that evening and so remained until well after dusk, but as it grew dark I was forced to return home for the night.
Back on site very early next morning I was relieved to discover that the big moment had yet to arrive.
Camilla remained suspended from the Honeysuckle leaf until 09:11 on Day 24 when she suddenly popped out of her chrysalis in the blink of an eye, annoyingly while my back was briefly turned!
Camilla luxuriated in the warm morning sunlight streaming through the oak canopy, slowly expanding her glorious wings as she clung to the vacant ‘exuvia’.
By 10:50 her wings were fully expanded and at 11:12, two hours after emergence, she clambered nimbly up onto the Honeysuckle leaf which had supported her pupa through sun and rain, heat and cold, for the past 24 days. It would now become her launching pad.
And then 8 minutes later, at 11:20 she flew for the first time… and was gone!
Except that I strongly suspect she hung around…
I only witnessed one other adult White Admiral in the wood that summer. The individual photographed below frequented Bramble blossom within metres of Camilla’s hatching site, sunning itself on the woodland floor nearby and alighting on Honeysuckle, likely assessing suitable spots to lay her eggs for the next generation of White Admiral caterpillars to emerge.
To be continued…
Buy & license more White Admiral images from my photographic website.
After emerging from hibernation in early spring common toads (Bufo bufo) migrate back to their breeding ponds at night. Sometimes this involves crossing busy roads and many toads are sadly hit and killed by passing cars.
Each year volunteers working with charities such as Froglife and local Amphibian and Reptile Groups attempt to ferry migrating toads, frogs and newts to safety at known crossing points.
Male toads grasp females in a position known as ‘amplexus’ as they attempt to fertilise her eggs. Often a mating pair can be found together before they reach the nearest pond. When this happens males hitch a free ride!
I was delighted to see my work featured in Erica McAlister’s new book on diptera: ‘The Inside Out of Flies’, published by London’s Natural History Museum last month.
The photograph in question shows hundreds of eggs laid by a member of the horse fly family (Tabanidae).
Erica uses the reproductive strategy of horse flies to illustrate r/K selection theory:
r-selected species are seen as more opportunistic and are able to propogate more quickly if the environment is suitable, whereas K-strategists spend more time investing in a few offspring to give them whatever competitive advantages they can to prosper in what are often already crowded niches
The original image from my archive is shown below:
The fly orchid (Ophrys insectifera) is usually found on chalk and limestone soils in open deciduous woodland and scrub, but is also recorded from grassland and chalk-pits. It is rare in the UK and even at known locations can be difficult to spot.
Fly orchids in woodland clearing. Surrey, UK.
Fly orchids are in flower between May and June. At this time they attract male digger wasps (Argogorytes mystaceus) with a scent which closely resembles the female wasp’s pheromone.
Males attempt to copulate with the orchid and during this process pollinia become attached, which may be carried to the stigma of another flower, completing pollination.
Digger wasp attracted to fly orchid flower.
Male digger wasp pseudo-copulating with fly orchid.
Fly orchid pollinia attached to the head of male digger wasp.
I was finally lucky enough to observe and document this behaviour in the Surrey Hills earlier this year.
Advancing conservation science through public engagement on digital platforms
Working for the local branch of Butterfly Conservation I developed an online system to document sightings of butterflies submitted by members of the public in Dorset.
This ‘citizen science’ project encourages engagement in nature conservation and adds to our knowledge of these vital environmental indicator species.
In 2018 more than 44,000 butterflies were successfully recorded using this method.
Initially butterfly spotters are directed to a web form which collects personal info, location details including grid reference, and species observed.
This information is then inserted into the Dorset Branch web sightings database.
Local experts are given password-protected access to a record management interface on the branch website. Recently submitted butterfly sightings can be reviewed and verified with a single click.
Questionable records can be studied in more detail and recorders contacted to clarify information as necessary.
Verified records are instantly published to the branch website, using a number of graphical representations for easy interpretation.
Butterfly sightings received via the website are archived online for the public to explore in greater depth.
Casual sightings received via the branch website provide a useful snapshot of butterfly activity in Dorset. But for research purposes it’s necessary to combine them with data from formally structured butterfly transects and other recording schemes within the region and nationally.
Website data is exported to the national society’s database annually. National butterfly recording cycles run for 5 years, at the end of which an ‘atlas’ is produced, showing the updated distribution of species and population trends.
To encourage recording in under-represented areas an interactive ‘White Holes’ map is published on the branch website. This combines data from the national database with more up-to-date regional web sightings.
It’s possible to use this map on a GPS-enabled mobile device to locate the nearest White Hole for observation. A list of previously recorded species for each 1km square is also presented.
Over the past 4 years this recording system has gathered more than 180,000 individual butterfly records, contributing to our understanding of these beautiful creatures and the changing environment they inhabit.
Experiment in environmental monitoring using a small consumer drone
For a few months now I’ve been experimenting with the use of a small camera drone for environmental monitoring. The quality of the resulting images and the unique perspective it offers have been pleasantly surprising. Its potential applications at relatively low cost are impressive I think.
In late 2017 Surrey County Council, in collaboration with Surrey Wildlife Trust, decided that this Site of Special Scientific Interest (SSSI) would be a suitable venue to pilot their commercial felling operations in the county.
A licence issued by the Forestry Commission permitted them to extract 30% on 2 occasions over a 10 year period. Upon visiting the site however the impact at ground level looked far more extensive than I would have expected.
Concerned that contractors may have exceeded their remit and damaged the Scheduled Ancient Monument in the process I mapped an area to the north of the site, flying the drone in parallel lines at a height of 60 metres with the downward-facing camera set to take pictures at intervals every few seconds.
With the help of DroneDeploy’s internet cloud software I then stitched the resulting 139 overlapping images together to create an orthomosaic map layer.
Tracks left by the contractor’s heavy machinery can be seen running across the circular ‘henge-like’ earth bank feature.
To help peopIe unfamiliar with the site to visualise the monument in context I then generated a 3D model from the visual point data using DroneDeploy’s online competitor, Pix4D.
For terrain features and dense canopy this technique works well, but it struggles to accurately represent isolated trees and finer features. Without resorting to an expensive aerial LiDAR platform it would be difficult to achieve better results however.
The little drone done good on this occasion, and with minimal disturbance to this historically and environmentally sensitive site ironically.