Holyrood and Duddingston/Bawsinch Damselflies and Dragonflies - 2005

Introduction

This document provides a species account of the distribution of Odonata in Holyrood Park and Duddingston/Bawsinch for the summer 2005 season. It is a summarised version of the original, excluding as it does the recommendations for further work, the detailed species records and the maps showing the locations of the ponds themselves. A full length electronic copy can be obtained from the author.

Background

The Scottish Wildlife Trust Invertebrate Survey of Bawsinch and Duddingston Loch (Hawkswell and Sommerville, 2003) recorded the presence, at least historically, of Blue-tailed Damselfly (Ischnura elegans), Azure Damselfly (Coenagrion puella) and Common Darter (Sympetrum striolatum) in the reserve. The only Odonata recorded during the survey itself was Black Darter (S. danae), but historical records for this species were also mentioned in the report. Also, anecdotal evidence suggested that at least two species, namely Emerald Damselfly (Lestes sponsa) and Black Darter, had been lost from the Bawsinch reserve in the recent past with Large Red Damselfly (Pyrrhosoma nymphula) as a gain. Within Holyrood Park itself, the SWT Invertebrate study of Holyrood Park (Saville and Sommerville, 1991) refers to “50 Common Blue Damselfly (Enallagma cyathigerum) at Dunsapie Loch” but after that date only incidental observations indicated the presence of any Odonata in the park.

In addition to the above, discussions with the Bawsinch convenor, the Historic Scotland Ranger Service and the Lothian Wildlife Information Centre during early 2005 suggested that while there was a body of knowledge extant on the Odonata of the area, little if any systematic survey work had taken place for a number of years.

In order to at least partially rectify this situation a survey was undertaken in 2005 to identify the Odonata species currently present in the area and to gain an understanding of their current distribution and breeding behaviour.

Methodology

The areas surveyed were:

St Margaret’s Loch
Hunter’s Bog
Wells o’ Wearie (3 ponds south of the Innocent Railway)
Duddingston/Bawsinch reserve
North side of Duddingston Loch from the Boat House to Hangman’s Rock
Dunsapie Loch
Accessible slopes between the Crow Hill / Nether Hill tops of Arthur’s Seat and the Duddingston to St Leonards Road

In each case, as well as the water bodies themselves, the surrounding vegetation areas were also examined to determine the limits of Odonata movement away from actual or potential breeding sites. Please note that while Holyrood Park is a site of Special Scientific Interest this does not guarantee unrestricted access to any of the areas mentioned.

Constraints

Time constraints did not allow the Glebe Meadow, the 4th Wells o’ Wearie pond or the west end of Duddingston Loch north from the Innocent railway to Hangman’s Rock to be surveyed in 2005.

Methods and equipment

Surveys were carried out in line with the weather condition parameters employed for the Butterfly Monitoring Scheme (BMS, 2005). Counts were only made under suitably warm and bright weather conditions, when wind speeds were light, and between the hours of 11am and 4pm. The minimum BMS criteria are either 13-17ºC with at least 60% sunshine, or 18+ºC without rain (can be cloudy).

Counts were taken by species for each location along with separate counts of any Odonata copulating or ovipositing. Visits were made from 30th May to 5th September, but due to time constraints they were made with highly varying frequency. Also, again due to time constraints, where a site was noted as clear of Odonata for more than two visits it was excluded from subsequent survey work during the season.

Binoculars (Swarovski EL 8.5x42) were used to examine the Odonata seen and the species identification was subsequently checked against Dragonflies and Damselflies of Great Britain and Ireland (Brooks and Lewington, 2004). Where a species could only be identified down to “Common Blue / Azure” this is included as a comment in the detailed records section, but has been excluded from the sections on results and commentary. In practice it was generally found possible to make the above species split for adult males at a range of up to 5 metres, with the darters and hawkers being spotted and identified at up to 30. In a few cases photographic records were obtained of species ovipositing, allowing retrospective identification when none had been possible in the field. Few solitary adult females could be identified with confidence.

Analysis methods employed

Due to the variable frequency and unequal number of visits to each location, the analysis carried out to date is a simple illustration of peak counts by species and location. A more systematic scheme of visits in the future might allow the production of a year on year “abundance index” for individual species.

Results

Peak Species Counts

Large Red Damselfly - 5
Blue-tailed Damselfly - 26
Common Blue Damselfly - 37
Azure Damselfly - 5
Common Hawker Aeshna juncea - 3
Common Darter - 21

Breeding Activity Observed (Copulating pairs / ovipositing females)

Large Red Damselfly - Yes
Blue-tailed Damselfly - No
Common Blue Damselfly - Yes
Azure Damselfly - Yes
Common Hawker - No
Common Darter - Yes


Noted range of flying periods

Large Red Damselfly - Seen from 30/05 to 05/07
Blue-tailed Damselfly - Seen from 24/05 to 25/08
Common Blue Damselfly - Seen from 03/07 to 01/08, but incomplete counts in early season
Azure Damselfly - Seen from 24/05 to 26/07, but incomplete counts in early season
Common Hawker - Seen from 13/07 to 01/08
Common Darter - Seen from 22/07 to 05/09, but could be present through into early October depending on weather conditions and habitat

Discussion

Methods

Site surveys would be better continued for all sites through to the end of the season in order to avoid the possibility of the emergence of any late broods.

Issues around the identification of female Odonata are not considered a major constraint to understanding at this stage as there were no instances of a site only being populated by unidentified females or a high preponderance of females over males.

Duddingston/Bawsinch

The area of Butterbur north and west of the Carse Pond and the Butterbur north and east of The Outlet (between the Carse Pond and the Gunn Pond) appear to provide important early season resting areas for Damselflies. These areas were gradually abandoned as the Butterbur grew, after which time the Damselflies tended to be seen over the Carse, Gunn, Rock Trap and Volunteer Ponds, with a single Common Hawker being seen over the latter pond in late July. Hangman’s Rock and the area of short grass immediately to the east provided a major resting and copulating area for Common Blue Damselfly through into July.

The Rock Trap pond was noted as an ovipositing site for Large Red and Azure Damselfly, with the Gunn pond being used for ovipositing by Common Darter.

It should be noted that the area of Butterbur between the Carse Pond and The Outlet will be removed as part of the planned reed bed extension during winter 2005/6. The effects of this change will need to be monitored in subsequent surveys.

Holyrood Park

Dunsapie Loch continues to provide a breeding site for Common Blue Damselfly, but numbers appear to be significantly reduced from those reported in 1984 (Saville and Sommerville, 1991).

Hunter’s Bog now appears to support Blue-tailed Damselfly, along with some Common Darter and an occasional Common Hawker, although there is no evidence to date to confirm the breeding of any of these species.

The west and east ponds of the Wells o’ Wearie south of the line of the Innocent Railway support breeding Common Darter, with Common Blue Damselfly and a single Common Hawker also being noted. The water quality of the middle pond appears to be different from the other two and this issue has been raised with Joe Muir (the Historic Scotland Park Manager).

This survey suggests that St Margaret’s Loch remains entirely empty of Odonata for reasons unknown.

Conclusions

The summer 2005 Odonata survey of Holyrood and Duddingston Bawsinch in Edinburgh established the presence of six species. This list included Large Red Damselfly (Pyrrhosoma nymphula), a local biodiversity action plan priority species (Edinburgh Biodiversity Action Plan, 2004). This survey recorded no Black Darter (Sympetrum danae) at any of the sites suggesting that this species has been lost to the area at some point since 2003.