The Lyons Share

For the last two days I have carried out an aquatic invertebrate survey of Waltham Brooks. I  recorded seven species of leech there and have become quite taken with these bizarre animals. There are not that many leech species in the UK and they are not too hard to identify. So here are a few of my favourites and what they feed on. 

This is Hemiclepsis marginata. It feeds on fish and this is the only one I have ever seen. It has  a chequered margin to the body, is quite broad and has a large shovel shaped head and a big banded suction cup at the rear. Quite the looker.

When I used to do the electro-fishing for the RSPB, this is what I used to know as the Fish Leech Piscicola geometra (not knowing there was another species) regularly seeing it attached to fish. This is VERY thin and worm-like with a similar large head and suction cup.

Another one I had not encountered before. Glossiphonia heteroclita and this one feeds on molluscs. A different array of eyes to the following species.

And the darker Glossiphonia complanata which has  different eye arrangement of a 2 x 3 matrix. This also feeds on molluscs but Elliot & Mann states they get their first meal from...other leeches! That dark internal structure on these two species is the crop!

This is the Duck Leech Theromyzon tessulatum. I think someone needs to tell it that's not a duck. Wait, it's not a duck right? Actually it feeds on water birds, usually entering the nostrils. It has been known to even kill ducklings. 

This small leech has two eyes and a dot behind them called a 'callous dorsal scute' in Elliott & Mann. This is Helobdella stagnalis and feeds generally on aquatic invertebrates.

Last Saturday I ran a course for the Freshwater Habitats Trust's PondNet project up at Chailey Common. I've just got around to identifying everything. We only really had time to sample four ponds in detail but we also managed a quick diversion to a number of other sites around the common. We started with a couple of small man-made ponds full of Bog Pondweed, Floating Club-rush and Marsh St. John's-wort. These ponds are very acidic, with dark peaty water so we expected to find the more specialist aquatic invertebrates. I told everyone we would see the distinctive Notonecta obliqua, the most distinctive of our four backswimmers and it was indeed the commonest bug in the pools. We actually recorded all four of our backswimmers in these four pools. In the above image one of our (around 40) species of water boatman (this one of two species of Hesperocorixia recorded in this one pond) can be seen in the background. Most backswimmers are much bigger than water-boatmen, it helps to be bigger than things that you eat!

Nice to see some Marsh St. John's-wort and Floating Club-rush.

The first pool had two species of Dytiscus in and it was nice to be able to key these out in the field. Thanks to Fran Southgate for this photo of the commoner Dytiscus marginalis on the left and Dytiscus semisulcatus on the right. However the nationally scarce Hydrochus angustatus was perhaps the most interesting being a species I have not recorded before.

One pool had an adult 13-spot Ladybird in it and I'm pretty sure that this is also the larva but it looks a little bedraggled.

This is the most Floating Crystalwort Riccia fluitans (one of  our few aquatic liverworts) I have ever seen. You usually see a few little plants floating on the surface, not a huge mass like this!

We called in and had a look at the Marsh Gentians on Romany Ridge that have responded to the grazing there. A great success.

But the highlight for me has to be a diversion to Lane End to look for the Mud Snails that were relocated there last year after not being recorded for many years. The dried up woodland pool they were found in looked quite unsuitable for anything else. In fact next to nothing else was found in there but we did see two Mud Snails! This is typical for this scarce species. It was very dark and dingy in the woods by this time so apologies for the photo. Note to self: next time look for this first. Look at the state of the kit!

A big thank you to everyone who attended. a full species list will be send to the Freshwater Habitats Trust and the records synced with the SxBRC as always (I've nearly entered 10,000 records already this year!)

So, here is the full list which includes 14 aquatic bugs, 15 aquatic beetles but only two molluscs (acid sites are not so good for shell building). Here are my records for the day including a few random things like Devil's Fingers that are nothing to do with aquatic life.

Must be one of the best names in natural history and I found a couple of these tiny snails on Thursday at Filsham Reedbed. Alice and I have started an invertebrate survey there to inform management and I was pleasantly surprised to have recorded 53 species on a cold day in March! That's just the species I could identify quickly. We have adopted the 'timed-count' methodology which has been so useful at other sites. Sieving was the main method we were using this time though rather than beating or sweeping and it was really productive! 

So far I have identified 23 beetles, 8 snails, 8 bugs, 7 spiders, 2 leeches, one moth and earwig. Eleven of these were new to me but the species I was perhaps most pleased to see was this tiny snail, Vertigo antivertigo. At 1.5 mm long, it would have been really easy to overlook it. I did manage to 'ping' one specimen with my forceps as I was trying to count the teeth!

Other highlights included three nationally scarce carabids; Demetrias imperialis, Odacantha melanura and Pterostichus anthracinus. I managed to identify a couple of female money spiders too, including the oddly patterned Lophomma punctata. This survey will carry on until the September or October and is the first completely in-house invertebrate survey we have carried out at the Trust. I expect we will get quite a list and learn lots about the site. Also heard my first Bearded Tit at Filsham. My list stands at 4192 species.

What a difference a space makes. I am not referring to my own bouffant, rather the aquatic macrophyte Hairlike Pondweed. Not the most inspiring of photos I am afraid but a tick for me all the same. I have been at Amberley Wildbrooks today, discussing management issues there with the RSPB and a number of local experts. It was a great meeting and the rain held off. I managed five ticks including four vascular plants which was an added bonus. 

The rarest of which was probably Cut-grass, although I didn't manage a photo. I will have to go back and get another shot later in the summer when we do the ditch monitoring. We also saw the rather impressive Sharp-leaved Pondweed, another rare species that is common enough at Amberley.

And not forgetting Great Water Parsnip which was not in flower, yet another new species for me.

Finally, we were pretty sure this was Horse Leech. I know there are not that many species of leech in Britain, certainly not ones this big. Quite an ugly brute. I end the day on 3437 species.