Scientific Illustrator Out & About – Biolblitz and Freshwater Life - July 19th 2013

Story posted: Friday, 19. July 2013 by Lizzie Harper

I recently went to a “bioblitz” day organised by Radnorshire Wildlife Trust at their nature reserve in Tylcau hill.  For a natural history illustrator, such an event is inspiring and educational.

I enjoyed the whole day enormously, and learnt a tremendous amount, especially about insects, thanks to the endless knowledge and enthusiasm brought by Phil Ward of RWT who also happens to be the entomologicval recorder for the county.  I now know my reed beetle, dock beetle, upland click beetle (a beauty), and have got a great deal better at spotting animals of all descriptions; including little froglettes which we encountered repeatedly.

Lizzie Harper natural history illustration of the life cycle of the common frog

Life cycle of the common frog, including froglette stage

Towards the end of this extremely interesting and enjoyable day, we took on the task of seeing what was living in the stream that runs through the reserve.  We did this by stirring up a prescribed length of stream (which related to the stream width) for exactly three minutes, and catching everything we disturbed, then going through and identifying it to family level (further classification to genus or species was done by Phil Ward and other keen entomologists later on).

Idealised illustration of an upland stream done for Natural England by Lizzie Harper

Idealised illustration of upland stream done for Natural England showing species common in similar habitats

We were surprised not to find any bullhead fish as they’re common in streams such as this one; the reserves manager for RWT was keen to see if we could spot any fish at all – to no avail on this occasion, bar one tiny fry.

Lizzie Harper scientific illustration of European Bullhead fish

European Bullhead

However, the invertebrate life we gathered was vibrant, diverse, and fascinating.  The number of mayfly nymphs was amazing (and encouraging.  They tend to thrive only in very clean and oxygenated streams); and we learnt that these can be burrowing, free-swimming, or live flattened against rocks.  Nymphs graze on plants or algae; the burrowers may feed on silt in the mud.  The adults have no mouth parts and all emerge simultaneously.  No-one is sure why, but the final stage of mayfly nymphs emerge from the water, and are able to fly, before they turn into mature adults.

Lizzie Harper natural history illustration of adult mayfly

Adult mayfly

We found many different caddis fly larvae; some had built pebbly homes flat on the underside of stones; others had constructed intricate turrets from tiny grains of sand,; others had cobbled together a home from pebbles, and another species favoured snippets of twig, all laid vertically together, to make their homes.  Each type of case was created by a different species of caddis fly larvae.

Lizzie Harper natural history illustration of caddis fly larvae

Caddis fly larva

We also found stonefly nymphs, and alderfly larva (who differ in appearance to mayflies in having a single, feathery tail rather than three long tails).  Freshwater shrimp were in evidence too.

Lizzie Harper scientific illustration of stonefly larvae

Stonefly nymph

 

Lizzie Harper natural history illustration of freshwater shrimp

Freswater shrimp

Fired up by this day out, I immediately became a family member of RWT, then I ordered a whole clutch of fold-out charts, produced by the Field Studies Council.

Thus armed, I went stream dipping a little closer to home, in the little river Edw near Erwood in Powys, and found some new organisms as well as caddis fly and mayfly nymphs.  The most fascinating were the leeches.  Only one species of leech will take human blood, the medicinal leech, and this is unfortunately now very rare (and not present in our sample).

Lizzie Harper scientific illustration of the medicinal leech

Medicinal leech

Watching the leeches move in the Tupperware tub was a treat; the way they extended and contracted themselves was incredible, and their undulating swim was beautiful to behold.

We also found beetle and fly larvae, and large rafts of blueish springtails.

Consulting the FSC Guide “The Freshwater name trail” I followed the instructions on how to calculate a biotic index for the habitat.  This is done by adding up a series of “scores” given to stream animals, then dividing the total by the number of animal types found.  Scores vary from 0 (no life) to 10 (clean and unpolluted stream).  Our score at Aberedw was 6.7, and so I realised this stream was a little more polluted than the one we examined in Tyclau Hill with RWT.

I’d expected to come across dragonfly and damselfly larvae

Lizzie Harper scientific illustration of Large Red Damselfly adult emerging from its nymph case

Large Red damselfly adult emerging, leaving exuvia of nymph behind

but a little research shows these are uncommon in streams (although you do get demoiselle nymphs and adults in running water).

Lizzie Harper natural history illustration of beautiful demoiselle

Beautiful demoiselle

Not only have I learnt lots from the biolblitz, and been able to re-visit past natural history illustrations of freshwater life, but I’ve also rekindled my passion for seeking out life in streams and ponds; I can’t describe how thrilled I am to be paddling about in streams with a guide-book and a magnifying glass again.  I tell you, this is the life!

Category:  Scientific Illustrator out and about   |   Comments:  2   |   Viewed:  2495

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A grand day out

Thursday, 18. July 2013, 23:21:24 – Erica cinerea:

It's a tough job, Lizzie, but someone has to do it! Sounds like a great day, and very educational too. Great that you were able to have a look in your local streams afterwards. I've always loved caddis-fly larval cases - they seem so improbable! And who couldn't like dragonflies. Your illustrations are wonderful as always. Thanks!


A grand day out

Thursday, 18. July 2013, 23:22:04 – Erica cinerea:

It's a tough job, Lizzie, but someone has to do it! Sounds like a great day, and very educational too. Great that you were able to have a look in your local streams afterwards. I've always loved caddis-fly larval cases - they seem so improbable! And who couldn't like dragonflies. Your illustrations are wonderful as always. Thanks!