MELROSE MEADOW 2001 BUTTERFLY TRANSECT
MANAGEMENT OF MEADOWS FOR INVERTEBRATES
Ian Duncan, Butterfly Conservation, Chairman West Midlands Branch
Butterfly Conservation Transects
Since 1976 Butterfly Conservation has been coordinating a number of butterfly transects throughout the UK. At present there are 19 walked in Worcestershire covering a wide range of habitats. These transects are a way of measuring the number and variety of butterflies present at a site from year to year. As butterflies are sensitive environmental indicators they can also give information on the quality of a particular site.
Recording takes place once a week from April 1 to the end of September. Walks are only carried out between 10.00 and 17.00 and only when a particular set of sunshine and temperature conditions are met. The same route is followed each week and all the butterflies are counted within 2.5 metres on both sides and 5 metres ahead. At the end of the season the data are collated in the form shown in the table to provide an annual index (total number seen) for each species.
Transect walkers may also record other invertebrates. I usually count moths, grasshoppers, crickets and bumblebees as well as butterflies.
Melrose Meadow Wildlife Reserve
Melrose Farm meadows comprise two unimproved grassland meadows and an old orchard covering 2.2 hectares and form a reserve owned by Worcestershire Wildlife Trust. They lie within the Parish of Hanley Castle 2.5 miles WNW of Upton on Severn. The main interest of the reserve lies in its unimproved grassland of NVC type MG5 (neutral-grassland). Traditional management of the site involves cutting hay in July followed by autumn grazing.
My usual transect is on Castlemorton Common mostly across unimproved grassland which is never mown, only grazed. I switched to Melrose Meadow this year as Castlemorton was out of bounds due to the foot and mouth outbreak. My main purpose in writing this note is to highlight the striking differences between these two grassland areas and in particular to record the devastating effects of the July mowing on the invertebrate population.
I recognise all my observations are based on circumstantial evidence only however I think in a general sense they are noteworthy.
The main points are as follows:
|I recorded many fewer invertebrates on Melrose Meadows than Castlemorton Common.|
|Numbers of Orthoptera were particularly low, so low in fact I only recorded a handful. This is in marked contrast to Castlemorton.|
|Crambid numbers were also orders of magnitude lower than on Castlemorton.|
Bumblebees were in reasonable numbers until the hay meadow was cut; they then disappeared almost completely in the absence of nectar sources which had been cut.
However, the biggest change occurred after the mowing of the meadows in mid-July see table. This week was probably the peak for butterfly numbers and the population crashed following the hay cutting which unfortunately left no uncut margins to the meadows.
Numbers declined by almost 40% in the following week and had declined by over 80% in three weeks. This contrasts with a typical season on Castlemorton where three weeks after the peak, numbers have only declined 12-20%.
I appreciate that these meadows are nationally important and must be managed for the main interest i.e. the grassland. However I think the results above raise some fundamental questions about the management of hay meadows. Can we not do more to help the invertebrates?
I suggest the following are considered:
|Leave an uncut margin around the meadow and an uncut "headland".|
|Leave some nectar sources uncut throughout the meadows.|
|Does the meadow have to be cut around the peak of the butterfly season?|
|Does the meadow need to be cut every year?|
I would welcome any thoughts on this subject.
PS HELP WANTED: We are always looking for new transect walkers . Please give me a call on 01684 568415 if you are interested. We would like to find walkers for Trench Wood and Perry Wood (Worcester) for 2002.
|MELROSE MEADOW TRANSECT 2001|
|No. of Species||2||0||4||2||3||1||6||5||5||6||11||9||8||6||5||5||6||5||2||2|
|No. of Butterflies||2||0||7||4||16||8||13||16||43||160||226||230||145||109||40||76||19||11||8||7|
|NR = Not Recorded|
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