VC37 (WORCESTERSHIRE) BUTTERFLY TRANSECTS ANNUAL
This Annual Review is based on information gathered from the transect walking data within VC37. Data is transferred from paper to the Transect Walker software, which is freely available from Butterfly Conservation's website (www.butterfly-conservation.org/features/transect_walker/). Individual transects can then be analysed to note trends according to changes in local habitat or fluctuations in species numbers according to yearly cycles. This data is then evaluated in the Butterfly Conservation's (BC) Regional Co-ordinator software (forming the basis for much of the data which can be found here).
This year we have compared this "Regional data" to the National Indices supplied from the "Butterfly Monitoring Scheme" (BMS). The national indices can be interpreted as indicators of national status, especially where BMS coverage is representative throughout the UK. The regional data, collated by the West Midland Branch of BC is based on 141,416 records since transects began in the region in 1982 of which VC37 has a significant part (32% of all transects ever walked in Gloucs, Herefs, Worcs, Staffs, Shrops and West Mids).
A full version of this document with comparison between Regional and National trends can be found at: www.WestMidlandsButterflyConservation.org.uk .
Once all the transect data is analysed, we can build a picture of the status of butterflies in the region, which can be compared to recent trends both regionally and nationally by use of an index value. A summary of this can be seen below. Although day-flying moths can be recorded using the butterfly transect method, there is very little data available. It is hoped in the future, more recording will be undertaken of day-flying moths, thus improving our knowledge especially of notable species such as the Drab Looper.
Small Skipper (14) - This has only been an average year, but increasing since the low of 1998. The regional data shows close agreement with the national data. In 2002 there were increases at 3 sites, decreases at 5 and 7 showed no change.
Essex Skipper (9) - Numbers at 3 sites have increased and 1 showed no change. This species continues to spread and is a good species to look out for in the coming years, although Small and Essex Skipper can be difficult to separate.
Large Skipper (16) - This has been an average year with good agreement with the national picture. 4 sites showed an increase, 3 a decrease and 9 showed no change.
Dingy Skipper (1) - Data is insufficient to generate a regional index as data comes from 1 site, where no change was observed. The national picture also shows a general downward trend.
Grizzled Skipper (1) - This species is recorded from 1 site, which showed no change. This year seems to have been quite a good one nationally with an increase over the previous few years.
Wood White (2) - BAP status: Species of Conservation Concern - No national indices available. One site showed an increase this year and 1 showed no change, but seems only to be an average year compared to the previous few years.
Brimstone (14) - A gradual decrease in numbers over the last 5 years has been seen. This decline has also been noted in other regions. Foot and Mouth affected the data from 2001. 5 sites increased, 1 decreased and 8 showed no change.
Large White (17) - This follows the national picture well year-on-year. This year 8 sites showed an increase, 1 a decrease and 8 showed no change, indicating it to be a good year.
Small White (17)- This follows the national picture, and proved to be a relatively poor year with an increase on 5 sites, decrease on 4 and no change on 8.
Green-veined White (17) - There is good agreement with the national picture for this variable species, this year being better than last. 8 sites showed an increase and 9 showed no change.
Orange-tip (17) - Numbers for his species mostly agree with the national picture. This year was a good year, showing some of the highest figures and a continual general increase after recent decline. Numbers increased in 2 sites, decreased in 2 and showed no change in 13.
Green Hairstreak (2) - Data for this species is now limited to only 2 sites, with 1 site loss (though not seen every year) and 2 sites showing no change. The national trend from the BMS shows a general increase over the last 14 years at monitored sites, although the BNM survey highlighted substantial declines in a number of English counties.
Brown Hairstreak (1) - BAP status: Species of Conservation Concern. This species is only found at 1 site and no national indices are available, as the species is poorly sampled by transects. It is a relatively stable species, with the most seen this year on transect. In 2002 there was the earliest ever sighting on a transect (15th Aug).
Purple Hairstreak (10) - Data is insufficient to generate a regional index. 1 site has lost this species, 3 showed an increase, 1 a decrease and 6 showed no change. The data does show this to be a relatively stable species.
White Letter Hairstreak (0) - No national or regional indices available for this butterfly, which is poorly sampled by the transect method. The data shows a general decline over the last 6 years. None were seen on transect at all in 2002!
Small Copper (12) - This follows the national indices nicely, showing its showing the cyclical nature of the fluctuations in abundance of this species. At the moment it is in quite a trough. This species has 2 generations per year in the West Midlands, but in the following years it appears to have had a partial 3rd generation: 1990, 1995, 1997, 1998 2001. This mostly correlates to the years with the and higher index values. There were 2 site extinctions, 3 increases, decreases and 4 sites showing no change.
Small Blue (1) - BAP status: Species of Conservation Concern - No national or regional indices available. In 2002 there was the earliest ever sighting on a transect (23rd May) as well as the latest ever (20th Aug). This species is only recorded on one transect, which showed no change.
Brown Argus (4) - Data is insufficient to generate a regional index. In 2002 there was the earliest ever sighting on a transect (21st May). This species has been lost from one site, numbers decreased at one and showed no change at 3. The regional picture shows a bad year with the 2nd . lowest ever index in the West Midlands. The regional picture does show a good similarity to the national variable trend over previous years.
Common Blue (13) - This agrees with the national picture and shows a rising index again this year from the low in 1999. Numbers at 5 sites have increased, decreased at 1 and showed no change at 7, although are still well below the previous highs in 1990 and 1996.
Holly Blue (16) - Fluctuations in the regional indices for this cyclical species correspond nicely with the national figures, with a recent low in 2000. There is a rising trend over the past 2 years with increases at 6 sites and no changes at 10.
|White Admiral (7) - This species has
again shown another poor year at the 8 sites on which it
is recorded. One site showed an increase, 1 a decrease
and 5 showed no changes. This is the 4th year in a row to
show a decline, roughly in line with the national picture.
Red Admiral (14) - This species has populations boosted from migrants, which were poor this year. Only one site showed an increase with 9 showing a decrease and 4 showing no changes this year. This gave the 2nd lowest index ever in the region, whilst a general rise has been seen nationally recently.
Painted Lady (12) - In 2002 there was the latest ever sighting on a transect (9th Oct). This species, like other migrants, shows great variability from year to year, with the last major invasion being in 1996. Although the data shows an increase this year on those in the 90s, few were recorded, with 1 site increase, 2 decreases and 9 showing with no changes.
Small Tortoiseshell (16) - The regional and national pictures are similar, with a gradual increase over the past 5 years. 5 sites this year showed in increase, 2 showed a decrease and 9 showed no change.
Peacock (18) - In 2002 there was the latest ever sighting on a transect (9th Oct). The fluctuations in the regional index are similar to those of the national one. This year was average with 5 site increases, 1 decrease and 12 showing no changes.
Comma (16) - This year was average for this species. It closely follows the national picture, with 6 site increases, 5 decreases and 5 showing no changes.
Small Pearl-bordered Fritillary (2) - BAP status: Species of Conservation Concern. Data is insufficient to generate a regional index. This species is recorded on only 2 sites, with 1 site showing an increase and 1 showing no change. As in the national picture, it was a good year with rising numbers compared to the low of 1999. However, BC nationally collated data highlights alarming declines from monitoring sites over the last 15 years. The butterfly remains widespread in Scotland, where remarkably it is the 8th most common species!
Pearl Bordered Fritillary (2) - BAP status: Priority Species. Data is insufficient to generate a regional index. This species is recorded on only 2 sites, 1 of which showed an increase and the other showed no change this year. Monitoring shows a general increase over the past 4 years and is similar to the national picture. We can be cautiously optimistic for this butterfly, which has undergone a massive UK range contraction in recent decades.
High Brown Fritillary (1) - BAP status: Priority Species. Data is insufficient to generate a regional or national index. This species is recorded on only 1 site (Malvern Hills), and continues to show a sad decline despite much conservation effort.
Dark Green Fritillary (0) - Data is insufficient to generate a regional index. The species was recorded on no sites this year. It has shown to be in decline since 1997 nationally and 1995 regionally.
Silver-washed Fritillary (1) - BAP status: Species of Conservation Concern. This species also continues to show a decline since the peak in 1996, although numbers increased on the 1 site where it is recorded.
Marsh Fritillary (1) - BAP status: Priority Species. Data is scarce and insufficient to generate a regional or national index. This was recorded on only 1 site this year, where no substantial change was seen.
Speckled Wood (16) - The general increases and decreases in the national indices are reflected in the regional indices, except that the general regional trend shows stability rather than a general rise in recent years. This year has shown an increase in 6 sites, a decrease in 1 site and no change in 9 sites indicating that it was only an average year.
Wall (0) - The species was recorded on no sites this year. Nationally, it has declined drastically from the peak in 1989, and there is a similar regional picture.
Marbled White (9) - Fluctuations in the regional indices for this species correspond well with those nationally, with a general increase over the past 15 years. This year, numbers have increased at 2 sites, decreased at 4, showed no change at 3 and was lost from 1 site. This year was only average although numbers increasing from the 1989 low.
Grayling (1) - Data is insufficient to generate a regional index. This species is located at only 1 site (Malvern Hills), where no apparent change was seen this year compared to last. Its numbers have increased from the lows at the end of the 90s, reflected in the national picture. In 2002 there was the latest ever sighting on a transect (4th Sept).
Gatekeeper / Hedge Brown (15) - The fluctuations in the regional Indices for this species correspond well with those of the national indices, except for the greater growth in the end of the 80s. This year though was average showing a slight downward trend, with increases at 1 site, decreases at 5 and 9 sites showing no changes.
Meadow Brown (15) - Fluctuations in the regional indices correspond well with those of the national indices with a general decrease over the past 3 years. There is evidence from the indices of an approximately 5-yearly cyclical pattern of increases followed by decreases. Numbers increased on 2 sites, decreased on 8 and showed no change on 5.
Ringlet (15) - There is fairly close agreement between the fluctuations in the regional and national indices. The species shows a general regional increase since 1987 with this year having nearly the highest ever. Numbers on 4 sites increased, decreased on 2 and showed no change on 9. In 2002 there was the latest ever transect sighting (12th Sept).
Small Heath (3) - This species continues to show decline in the region and corresponds well to the national picture from BMS data. Data recently collated by BC from 388 UK Small Heath transect sites shows a mean annual decline from 1991-2000 of 4.4% per annum. If the trend continues, this would equate to 66% over 25 years, and the species would qualify as a BAP Priority! This year figures for the region showed all 3 sites with no change.
Transects Walked in 2002
|Transect||Recorder||Started||Principal Habitat||Conservation Status|
|Blackminster||Terry Knight||2000||Mixed edges|
|Briar Hill Droitwich Spa||Neil and Corinna Gregory||2001||Mixed edges||Wildlife Trust|
|Castlemorton Common||Ian Duncan||1998||Marshy grasslands||SSSI|
|Chaddesley Wood New||Steve Harper||1989||Mixed Woodland|
|Cleeve Prior||Terry Knight||1984||Broadleaved||LNR|
|Grafton Wood||John Tilt||1998||Mixed Woodland||SSSI|
|Honeybourne||Terry Knight||1998||Bare ground|
|Knapp and Papermill Reserve||Garth and Pam Lowe||1984||Neutral Grassland||SSSI|
|Malvern Hills North||Colin Dolding||1999||Dry grassland|
|Malvern Hills South||Digby Wood||1987||Bracken||SSSI|
|Melrose Meadow||Ian Duncan||2001||Neutral Grassland||SSSI|
|Monkwood 1||Claire Turner||1986||Broadleaved||SSSI|
|Monkwood 2||David White||1996||Broadleaved|
|Trench Wood||David White||1987||Woodland||SSSI|
|Uffmoor Wood||David White||1996||Broadleaved|
|Windmill Hill||Terry Knight||1982||Dry grassland||SSSI|
|Wyre Forest East||Terry Higgins||1984||Broadleaved|
|Wyre Forest West||Frank Lancaster||1988||Broadleaved|
Data Status on Transect Walker Software
This Map above produced from MapMate software shows the locations at 2km resolution of the VC37 transects.
|Transects Ever Walked||Total Years of data||Years of Full Weekly Data||Years of Annual Summary Only||Years of Annual Index Only||No of lost Years|
|32||290||181 62.4%||75 25.9%||3 1.0%||31 10.7%|
The table above shows the amount of data that has been
processed onto the Transect Walker Database. The ideal data set
is that with Full Weekly Data because individual sections of the
transect can then be studied.
Recording on the Transects
At present there are a few Transects where there is no walker(s), including Perry Wood, Shelfheld Coppice and Bredon Hill. If you would like to walk one of these transects or set up your own please contact Neil Gregory as soon as possible.
The West Midlands Branch of Butterfly Conservation are holding a Transect Training Day on July 27th at the Wyre Forest. If you are interested in setting up a butterfly transect or already carry out a transect but would like to learn how to use transect walker software please do join us for the day for a classroom session in the morning followed by an afternoon practical session in the Wyre Forest. Meet at the Wyre Forest Visitor Centre at 11.00am. Contact Jenny Joy on 01952 245684.
All-sites collated indices are produced by the Butterfly Monitoring Scheme run by the Centre for Ecology and Hydrology Monks Wood, Huntingdon and are used with permission. Our thanks go to all the recorders for all their hard work in 2002, BC Conservation Office, DEFRA and to Ian Duncan with help with this review. Transect Walker (1.3) and Regional Co-ordinator (1.33) software have been developed and made available thanks to DEFRA research funding to Butterfly Conservation.
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