Ocean Mist

Posted by Jes

Crabtree Reserve Report 2014

The Lullybeg transect was walked from April to the first week in October and the results have been forwarded to the National Biodiversity Data Centre. We have now submitted seven years of records for Lullybeg and the National Biodiversity Data Centre will be able to calculate a site-specific index so we will be able to track population changes specifically in Lullybeg, as well as having the national picture. The figures outside brackets refer to all butterflies counted on the site while figures inside the brackets are transect counts.

Species 2011 2012 2013 2014
Dingy Skipper

Green-veined White

Orange-tip

Large White

Small White

Cryptic Wood White

Brimstone

Common Blue

Small Copper

Red Admiral

Painted Lady

Small Tortoiseshell

Peacock

Dark Green Fritillary

Silver-washed Fritillary

Marsh Fritillary

Ringlet

Wall

Speckled Wood

Meadow Brown

Small Heath

Large Heath

17[11]

49[45]

45[41]

1[0]

4[2]

0[0]

14[5]

81[74]

18[17]

26[5]

0[0]

58[26]

22[13]

0[0]

1[1]

15[9]

185[125]

1[1]

7[3]

62[48]

88[70]

1[1]

31[28]

41[26]

11[11]

1[1]

4[2]

3[2]

36[14]

68[61]

23[10]

8[1]

1[1]

315[140]

168[53]

0[0]

4[0]

19[8]

154[104]

1[1]

49 [4]

180[126]

122[100]

1[1]

33[28]

106[86]

14[10]

1[1]

11[11]

1[0]

53 [21]

54[52]

17[8]

7[1]

2[0]

335[296]

233[123]

0[0]

7[3]

41[25]

550[405]

2[2]

38[8]

303[250]

231[199]

0[0]

23[23]

58[40]

37[25]

0[0]

23[19]

9[6]

44[26]

60[46]

8[2]

67[14]

1[1]

50[30]

111[79]

1[1]

22[8]

92[83]

685[519]

6[2]

30[6]

204[149]

229[155]

0[0]

Site Total 695 in 25 visits 1,240 in 25 visits 2, 039 in 26 visits 1,760 in 24 visits

.

The figures for 2014 come with a significant qualification; no counts were undertaken between 18/07 and 04/08/ when weather conditions were highly favourable. This period is part of the peak flight time which means that the figures omit many individual butterflies, notably numbers of the Peacock, Meadow Brown and Ringlet all species that produce high populations. Another factor that lowered the count was the cold weather during August which is an important month for the Common Blue, Small Tortoiseshell, Peacock and some whites.  The average temperature for the transect walks in 2011, 2012 and 2013 was 15.64 Celsius, 16.40 Celsius and 17.69 Celsius respectively. The average temperature for the transect walks in 2014 was 17.50 Celsius. The highest temperature recorded during a transect walk was 22 Celsius on 22/07; the lowest temperature was 12 Celsius on 24/04/.

The good conditions during much of the flight season during 2014 saw the general trends of abundance noted in 2013 continue. In 2014 April and May saw good sunshine and 127 butterflies were counted on the site compared with only 29 for these months in 2013. June saw beautiful weather while July’s conditions were benign throughout and especially sunny throughout the last two weeks providing ideal conditions for butterflies. As already stated August saw cool conditions but September was a beautiful month especially the last two weeks which saw beautiful summer weather return. September’s good conditions continued into October.

The notable features include the increase in numbers of Cryptic Wood White, Silver-washed Fritillary, Marsh Fritillary, Red Admiral and Wall Brown while the Dark Green Fritillary was seen for the first time since the transect was established. Big declines in the Small Tortoiseshell might be linked with its parasites while the Green-veined White, another common species, saw a dramatic but less drastic decline.

The management work carried out during the autumns and springs of 2011-2014 may have helped to improve the conditions for some species. Scrub clearing was carried out in February 2013 in an area that holds an abundance of Devil’s-bit Scabious (the food plant for the caterpillars of the Marsh Fritillary butterfly) in the hope that the Marsh Fritillary would breed there. A Marsh Fritillary butterfly laid her eggs on a plant in the cleared area in the summer of 2013, showing that conservation actions bear fruit. In 2014 three webs (larval nests) were found here and further clearing to increase the light reaching this area was carried out in November 2014. The most important finding is the continued recovery in the Marsh Fritillary population on the reserve. Only three Marsh Fritillary larval nests were found on the site in the autumn of 2012 and spring 2013. In the autumn of 2013, 15 larval nests were found. In the autumn of 2014 a record number of 37 larval nests were found including four on the river bank. The nests are currently more widely distributed than in all the years following 2007. While parts of the site remain in excellent condition there is significant scrub clearing needed especially on the southern side of the site while the grassland where most of the Marsh Fritillary nests are located is beginning to become rank and needs some attention; this can take the form of mechanical disturbance and grazing by cattle.

A final point to emphasise about the success witnessed at the reserve concerns habitat. Weather and climate which are important factors affecting butterfly populations  are beyond our control but habitat condition is capable of being influenced by human activity. There is little doubt that the Marsh Fritillary and probably other rarities would have become extinct on the site without our management. Thanks to our members and supporters including Bord na Móna for looking after the site and its wonderful Lepidoptera.

Note: The table published in the Annual Report 2013 contained errors that have been corrected. We apologise for any inconvenience.