When the new reception hide and facilities were built in
2016 the pond, that is now referred to as the reception pond, was created. It
was excavated in a clearing created from the removal of windblown larch and the
resulting clay topsoil was used to form the access ramp to the reception hide.
The pond is up to 2m in places and is mostly self-lined by natural clay but
there are pockets of peat around the edges, so some areas had to be bunded by
conventional pond liner and puddles clay. It was left to fill naturally, which
continues, from rainwater and the roof run off from the reception hide, acting
as an ‘aqua green’ to contain any excess water before it is released into the
surrounding ditches. When there was only 30cm of water the first inhabitants
were recorded; great diving beetle, several species of dragonfly, midge larvae
and the ‘endearing’ marsh frog. Since then the aquatic wildlife has been left
to colonise.
When schools visit, they have several activities that they
can choose to take part in and one of those is pond dipping. This gives the
children a great opportunity to do some very valuable scientific sampling. They
learn how to use the simple equipment safely and correctly to sample the water
from the dipping platform. They then use identification keys (FSC charts) to
name all the organisms that they catch, which they then record. The
identification key is not detailed to species level for many of the
invertebrates, but it is an appropriate tool for primary age pupils to use as
they rarely have undertaken pond sampling before, so most organisms are new to
them. Once back in the classroom we record everything centrally giving an
indication of species diversity and abundance. The counts are not accurate full
counts, they are recorded as present or absent across the ten working groups,
eg a score of 1 is given if only one group found that species, regardless of
how many they actually caught. Since its creation the pond has only been
sampled by visiting school children, so their role is key in recording the
changing biodiversity of the pond and in so doing values the importance of
their work as visiting scientists on the reserve.
For last year, 2019, I have collected all the data and it
provides an interesting picture of how the pond changes over the year, starting
in April right through to November. In that time 25 species have been found; 23
invertebrates, 1 fish and 1 amphibian. The most common species throughout the
year, seen in every class sample, are lesser water boatmen, ramshorn snails,
stickleback and damselfly larvae. Some species; burrowing mayfly nymph,
stonefly and hairworm have only been recorded once over the year. Certain
species are found at certain times; marsh frog tadpoles are not seen until early
July as would be expected, whereas damselfly larvae numbers peak in the autumn,
suggesting that these individuals are overwintering in the pond, contrasting to
dragonfly larvae which are seen in abundance in June but are not recorded in
October and November. Stickleback numbers reach a peak in June and July, but
the data does not specify whether these have been adults or fry. The number of
pond skaters drop from the end of July and are not recorded in autumn. Ramshorn
snails and lesser waterboatmen as well as being recorded in every class sample
during the year are also the most abundant throughout the year, being seen by
large numbers of the groups in the class; in July all groups in the class
caught lesser waterboatmen.
From these records the pupils can see the biodiversity of
life in the pond and appreciate that some species are more common than others.
Their favourites have to be the sticklebacks and the marsh frog tadpoles, maybe
because these are species they are more familiar with. Research shows that
children are able to learn and retain specific species names and so introducing
them to burrowing mayfly nymphs and hairworms is beneficial to their subsequent
recall of a pond habitat and its feeding relationships. Highlighting the
tremendous jaws of a dragonfly larvae or the pincers of a pond stick insect
engage pupils with an unfamiliar but equally fascinating pond organism,
widening their knowledge and understanding of the pond as a habitat, adding value to the simple activity of pond dipping.
