Sorting litter at home and abroad

Since I finished volunteering on the BESS Earthworm Project I have been continuing to work in the Natural History Museum Soil Biodiversity Group sorting leaf litter samples on my day off. After the sieved leaf litter samples have spent three days in the Winkler bags the pots are removed and the alcohol containing the invertebrates (and hopefully not too much mud and debris!) is decanted into tubes ready to be sorted by volunteers. Each litter sample is poured into a petri dish and put under the microscope for sorting. If you are lucky the sample looks like this; a nice clean sample with not too much debris where the the invertebrates can easily be picked out and counted.

A nice clean Soil Biodiversity Group litter sample

A nice clean leaf litter sample ready for sorting

However sometimes the samples look like this! This one I had to split into parts and dilute in order be able to pick out the specimens from the murky alcohol. The invertebrates are identified to order level and each group counted into its own glass tubes which are labelled with the sample details and bundled together, some will eventually go on for species identification, and in the case of some tropical samples, DNA sequencing.

'Dirty' leaf litter sample - the stuff of volunteers' nightmares!A soil group volunteers’ nightmare!

I started off sorting litter samples from Borneo, these are from one of my many projects run at Stability of Altered Forest Ecosystems (SAFE). This site provides a gradient of forest modification, from primary rainforest to increasing levels of logging and fragmentation, and finally oil palm plantation. I was excited to work with tropical samples for the first time although I did not find them as different from UK leaf litter samples as I expected. Many of the groups were familiar, within the beetles there were Staphylinidae which I recognised as from subfamilies Pselaphinae and Aleocharinae; but every so often though I was reminded that I was ‘abroad’ when a sample turned up exotic invertebrates such as termites, scorpions and crickets.

Soldier termites in a Soil Biodiversity Group leaf sample from Borneo

Meeting soldier termites for the first time in a Soil Biodiversity Group leaf sample from Borneo
I also noticed that when samples had a lot of ants or termites they had very few other invertebrates, which was a striking illustration of how much impact these two groups have on tropical forest ecosystems. Sometimes the number of ants or termites in the samples can be very high indeed, this tube from one litter sample has over 200 individuals. A current joint project with the Soil Biodiversity Group and Kate Parr’s lab is investigating how termites and ants effect other soil and litter invertebrates by excluding them experimental plots. 
A tube of termites sorted from a Soil Biodiversity Group litter sample
Hundreds of termites sorted from a Soil Biodiversity Group litter sample
Some of my favourite invertebrates from the Borneo samples were these cute little scorpions and a fly with beautiful wing patterns. I am now back to sorting samples from the UK as we process those from the National Vegetation Classification project, which have a pleasing familiarity to my MSc leaf litter samples. Each sample has a different ‘character’ however so I never get bored, sorting Winkler samples to me as exciting as opening my stocking on Christmas morning – the old favourites are always there but you also never know what exciting new things there will be!
Scorpions and a pretty fly from Borneo leaf litter samples

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