Saturday 19 August 2017

Freshwater Life in Malham Outflow Stream

Have you wondered what little Ellie (in the Water Babies) would be finding when searching for water creatures with her tutor, Professor  Pttbmllnsprts?

Craven Conservation Group members set off to find out. - Sat 19  - a windy wet day in August.

On the way we found the patch of Spring Sandwort flowering with its pink anthers. (Yes is was the Sandwort - obviously thought it was spring and not summer weather)

Our equivalent of the professor was Sharon and Peter Flint.

We left the cars just south of the Tarn and marched down to find where the outflow stream would be sinking today.  A little way back up we found a wooden post lying in the stream. Sharon, with help, enthusiastically levered it up to see what was clinging on to it. "Such wood adds diversity" she said. "When beavers gnaw at trees and fell them, the trunks fall into streams and add diversity."

We put our finds in a tub - and then collected more organisms from the mosses and algae on the rocks of the stream.

We found a longer than wide snail: Bithynia tentaculata 

Everyone except me (for some reason) saw a Fingernail clam: Sphaerium corneum. These are bivalves (have two shells)  Their primary food sources are diatoms and other phytoplankton
Sharon told us how they are filter feeds and  "hoover up" gunge, and keep the lake clean.

Here is a Mayfly nymph called Serratella ignita  (Thanks to Sharon for the picture) 

We also found some stonefly nymphs. Mayfly nymphs have three tails and can swim and so move very fast in water. Stoneflies just walk or run in water. The stonefly nymphs we found were quite small - but they would be quite young, having just been laid earlier n the summer. They would grow bigger and shed their skins several times before next summer.

For one species we found Sharon said the male did not fly. When it emerges it crawls around on the rocks, waiting for a female fly and visit it. The females emerge from the water with their eggs ready developed.They visit a  male and then then eventually crawl back into the water to lay their eggs.

This is a picture of an empty pupa case of the caddis Ceraclea nigronervosa    The stone particles are held together by silky material. If the case had been closed, the pupa would have been inside. When the pupa needs to emerge it chews its way out.  These cases are relatively flat and can fit under rocks.

Oh, Sharon has just sent me a photo with the larva inside

There are 199 different species of Caddis in Britain, and one third of them can be found in and near Malham Tarn. 70. Not bad!!

The Yorkshire Naturalists Union did a lot of surveys and research over a period of five years in Malham Tarn in 1960s(?)
Peter and Sharon spent a year last year or rwo

Below is a cranefly larva or leather jacket. (See video)  "It bit me" said the finder. "Well a few cranefly larvae  are carnivorous  - though many eat plant roots   And and a few do live in water " said Peter.

Due to  concern that we might get sunstroke due to the intense heat,  (???)  we had a shorter trip than planned - but hope to arrange another day shortly. Let us know if you would like to come.

Moorland Art and Nature Walk

There's more to Yorkshire Moorland Ecology than Hats and Ducks.  A group of us set off on a small patch of moorland ten miles west of Ilkley Moor to find out. It is a day sponsored by North Yorkshire Open Studios.

We are led by artist Bridget Tempest who has the idea of linking art and all that goes on on moorland. She has enlisted the help of myself (botanist), Nancy (Landscape person),  a team of neighbouring young explorers and four aspiring artists

We met at Rushbank on the side of Broughton/Elslack Moor.

We have our sketchpads ready. "Look for the big shapes. Divide the page up into the main shapes - maybe sky, background area and foreground. Look at the patch of rushes above us. What shape does it make?"

An excellent demonstration of dividing the paper into shapes - by B aged 5.
And look, he's drawn Tufted Hair-grass in the foreground.

Sue has brought water colours.  Bridget gives positive feedback

The Heather is in full bloom

Before coming I have asked my friends in Craven Conservation Group "What animals we might find?"

"Oak Eggar Moth." they say.

Yes! We find one. - a male - and rather battered - but it is mid August.
 "The Fly that fishermen like" said Rae: "The Heather Fly or Red-thighed St Mark's Fly   Bibio Pomonae "

Yes! we find one. 
Several in fact, clutching on to Rush and Wavy Hair-grass stems, waving in the wind.- and they do look very, very juicy. This one comes back down to the studio - but we release it afterwards.

We find Heather-Beetles, Grass-Moths, a frog, owl pellets and various droppings.. rabbit, sheep, grouse, pheasant?

In my earlier visit I had noticed how the soil under the heather was clearly marked in different layers:-

Black at the top
Black line on top of
Red 1 cm thick hard pan
Grey with occasional red mottling
Crumbly grey sand and clay and bed-material

Yes it is a podzol!!

And not a worm (or duck) in sight.

This is because the soil made by the dead heather leaves is too acid for bacteria. So too acid for the soil to rot down, so nothing for worms to eat. So the worms don't mix the soil up and the different layers remain clearly separated.
We measure the acidity of the soil with BDH Universal Soil Indicator and the solution goes bright red - indicating a pH of 4 (very acid) 

When we get down to the track, surfaced with limestone chippings, the boys notice a molehill.

And in the molehill 

- a big juicy worm!

We measure the pH of the Molehill - the chemical goes green this time - pH 7.5 Yes, this soil is basic (the opposite of acid). So bacteria grow on dead vegetation and the worms have something to eat.

The boys point to the worm in the molehill

 We admire the view. Can you see Ingleborough in the distance - far left? And drumlins in the midground? (lots of little egg-shaped hills)

 Doris draws

I draw. 

Come out with us if we go again next year

Up above the Dale in the purple moorland patch
Pop up a possy of people - Look at them - Watch
One is pulled up by a rope.. attached to straining dog
The second flings hands in air shrieking  "Look, Look! a Frog!"

The third drops down from view, lost amonst the rushes
The fourth struggles on with wellingtons, through the boggiest of flushes
The fifths clambers ever upwards without a care or worry
through heather and cotton-grass and every type of berry (cran - bil - crow)

The sixth finds  pellets from an owl and droppings from a grouse
And searches and searches for hole of vole or mouse. 

The seventh has settled comfortably with sketchpad, paint and brush
The wind stops momentarily, there is a kind of hush
A red-thighed March-fly dangles precariously from an arching Hair-grass stem
Then flies off into space - No problem

Into space ...

That illusive cavity between interlocking spurs.. 
Above the hedge lined drumlins and the sycamores and firs
As far as Rye Loaf Hill and Ingleborough beyond
Up to the hanging clouds  hanging clouds 
hanging clouds.. hanging clouds..

to be finished at a later date.


Everything is interlinked.

Special fungi around heather roots can fix atmospheric nitrogen and make it into "fertilizer".

Air > Mycorrhizal fungus > Heather > bee > honey > Human > sewage sludge > Agricultural fertilizer..
Actually honey only contains a very tiny amount of protein..
I'll have to think through this one again

Air (As N2) > Mycorrhizal fungus > Heather > Sheep > Human > sewage sludge > Agricultural fertilizer > Air (As NH3 or NO) > Klebsormidium crenulatum.

Kebsormidium is the velvety green alga we saw growing on the gritstone walls, that is growing more and more each year.

Air > Mycorrhizal fungus > Heather > Heather Beetle > Meadow Pippit (or frog) > Owl > Owl Pellet > 

Hey we live in a marvelous world!