In 1991 David
Wheeler was appointed reserve manager, and set about familiarising
himself with the site and the existing plans. He made an assessment
of the condition of the rhos pasture on the western block as marsh
fritillary habitat and concluded that it was generally in poor
condition. Although the average sward height was 17cm in September
1991, there were some areas of rank sward above 30cm in height, and
there was more than 5cm of dense plant litter over much of the
pasture. Of particular concern were a number of large patches of
purple moor grass Molinia caerulea that showed vigorous growth
around the patch edge and appeared to be expanding. However, adult
index data showed that the butterfly population had recovered from
a crash following the high count in 1983, and the index of 1204 in
1991 was the highest it had been since 1984 (Fig. CS 4.3). The
first larval web data since 1984 was recorded in 1991. In 1984, the
web index was 95, which suggested a total of around 3.870 webs on
the site. In 1991, the web index was 154, confirming the high
population.
David decided that
larval web data should be collected annually. The web index would
be a useful compliment to the adult data. Much of the data would be
collected by David Woolley, who was the immediate NNR neighbour and
farmer at Llawrcwrt Farm. This was extremely fortunate as David had
an intimate knowledge of the site dating back to the early 1980s
and was an enthusiastic amateur entomologist. David Woolley
was also the main grazier for the NNR and was sympathetic to the
needs of the conservation management programme.
A period of
'recovery management' was required. The NNR had been grazed lightly
by cattle under grazing licence during the period June-September.
Stocking rates for the western block for 1991 were only 0.14
lu/ha/annum. I determined to increase the stocking levels, but the
condition of the pasture made this an unattractive prospect for
graziers, and no extra cattle were available. David Wheeler opted
to use winter grazing by ponies to break up the litter layer, and
in the winters of 1991 and 1992 a herd of up to 20 ponies spent
around 4 weeks on the western block during December/January. This
was only possible because there was suitable fall-back land on the
NNR in the form of agriculturally improved pasture. The ponies
spent the majority of the winter months here, and without the
improved pasture there was insufficient incentive to attract the
pony grazier to stock the NNR.
The first revision
of the management plan started in 1992 and was written in the
Conservation Management System (CMS. An objective was produced for
each of the SSSI features. Guidance at the time did not require
that the objective described a required condition for the feature
and so the use of a standard phrase 'maintain and enhance' merely
recognised that the status of each feature should be maintained and
implied that, if possible, it should improve. Attached to this
objective were a number of surveillance projects. Sward height data
and data on the status of the larval food-plant had also been
collected from The larval web transects. This data had the
potential to inform management and so it was logical to attach this
to the following objective statement.
1992 marsh
fritillary
'To maintain and
enhance the marsh fritillary population at Rhos
Llawrcwrt.'
