 |
| Brown Argus - A Scarce Species at Attenborough - © Sean Browne |
If the soggy summer is getting you down, spare a thought for
your local wildlife – in particular the butterflies. Prolonged wet weather
during the spring and summer months can literally spell disaster for these usually
abundant insects. A recent walk around the Reserve produced only a handful of individuals
including ringlets, meadow browns and a single red admiral thus giving an
indication of the true impact the weather might be having.
Whilst wet summers are not uncommon in the UK, this year we
have seen unprecedented levels of rainfall along with localised flooding and below
average temperatures. It is this combination of events that has started to have
an impact on many species of British butterflies – drowning and washing away
eggs, reducing food availability and grounding adults so that they are unable
to seek a mate.
Around 20 species of butterfly are typically recorded on the
Nature Reserve each year along with a few local rarities such as the purple
hairstreak and brown argus. Some of these, including the purple hairstreak,
have flight periods of just a few weeks – giving them a very short window of
opportunity to find a mate and lay eggs and putting them more at risk from
inclement weather. Most other species are more fortunate and have two generations
within a single year (usually one in the spring and one in late summer) or a
longer flight period. Many would have taken advantage of the warm and dry start
to spring to successfully lay their eggs, however those butterflies emerging
during the warm spell towards the end of May would have been confronted with
downpours throughout June.
As adult butterflies will not emerge from their cocoons until
the conditions are just right there are further concerns that if the cold and
wet summer continues it could result in delayed emergence of second generation
adults. The length of time that they will have to find a mate and lay eggs will
be subsequently reduced and this will in turn lead to further population
crashes next spring.
Butterflies in the UK are already suffering huge
declines through habitat loss with almost three quarters of species having
reduced in number over the last ten years. The recent wet weather can only add
to this situation. Whilst we have had wet summers in the past (one of the
wettest Junes locally being in 1982) wildlife habitats were once better
connected, via green corridors, and gave butterfly populations the opportunity
to recover more quickly.
How can you help?
The ‘Big Butterfly Count’ organised by Butterfly
Conservation runs between Saturday 14th July and Sunday 5th August 2012 and is
a survey that members of the public can get involved in to help build up a
picture of butterfly populations across the UK. These results will give the
first indications of the impact that the recent weather has had on butterflies
on a national scale. It only takes 15 minutes to complete and a full list of
information can be found at www.butterfly-conservation.org
