Heart of the Levels Local Area Group of
the Somerset Wildlife Trust. March 2012
Report on our Botany Study Group field
field work visit to Batty's Piece, Curry Rivel, March 6th
2012.
Members were given an introduction to
vegetation identification techniques. In other words , how to
identify in
the absence of flowers. Identification is the key to
any surveying technique and is most difficult when plants are not in
flower.
Batty's Piece is a 4 acre private
nature reserve off Holdens Way owned by a group of local residents
and maintained as an unimproved grassland meadow.
With fine weather it was ideal for this
introductory session. The field was purchased in 2005 and
professionally surveyed soon after. Approximately 120 different
flowering and grass plants have been recorded. It was declared a
Local Wildlife Site in 2007. A County Council Grant was obtained in 2008 for planting a new 200m hedge on the north side of the field. The planting was carried out by members of the Syndicate.
Members of the Group were introduced to
a range of surveying
techniques commonly used by amateur and professional
surveyors. Anne and John Bebbington led the session.
Members initially spent 10 minutes or
so to looking closely at the two areas selected for our field work
and then all were given a brief description of the general principles
of surveying and the methods to be used on this visit.
Members worked in
pairs and were tasked with surveying two 7 metre square plots, at
widely separated parts of the field which appeared to differ in their
vegetation. Pairs first carried out a subjective assessment of 16
selected species in each of the two areas using a modification of the
Braun-Blanquet scale (ACFOR).
A total of 12, 25
x25 cm square metal quadrats were then placed at 12 random
co-ordinates in each plot and the presence or absence (frequency) of
the selected species recorded. This sample size gave us an
acceptable coverage of between 1-2% of the total plot size.
The data was
collated over lunch in Drayton Village Hall and then discussed. The
subjective assessment showed some differences between the two areas
and this was confirmed by the frequency data. There were some
discrepancies between the results recorded by the two methods and
reasons for these were considered..
In further
discussion the relative accuracy of the two methods and how and
when they should be used was discussed . Members were also introduced
to techniques used by the Somerset Botany Group and in National
Vegetation Classification Surveys. We hope to spend a field day
using National Surveying techniques next year.
The fine weather made the day a most
successful and enjoyable experience. The next session in April will
be looking at spring wild flowers at a different venue.
David German 12.03.12
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