Monitoring of the Invertebrates of the Turf-Stripped Areas of Iping Common with an Emphasis on Heath Tiger Beetles – a 2013 Base-Line
Total Page：16
File Type：pdf, Size：1020Kb
Monitoring of the invertebrates of the turf-stripped areas of Iping Common with an emphasis on Heath Tiger Beetles – a 2013 base-line. Graeme Lyons & Shaun Pryor February 2014 Contents………………………………………………………………………………………………………………………………………………….Page Summary…………………………………………………………………………………………………………………………………………………… 3 Introduction…………………………………………………………………………………………………………………………………………….. 4 Methodology…………………………………………………………………………………………………………………………………………….. 6 Results………………………………………………………………………………………………………………………………………………………. 8 Conclusions……………………………………………………………………………………………………………………………………………….. 21 Acknowledgements…………………………………………………………………………………………………………………………………… 24 References and bibliography……………………………………………………………………………………………………………………. 25 Appendices Appendix 1: Raw data for identification difficulty rating 1 species and grid references of scrapes…….. 26 Appendix 2: Raw data for identification difficulty rating 2 species……………………………………………………….. 28 Appendix 3: Raw data for identification difficulty rating 3 species……………………………………………………….. 31 Maps showing locations and numbers of the scrapes………………………………………………………………………………..35 2 0 – Summary Heath Tiger Beetles were re-released onto Iping Common in the last known area they were known to inhabit there, Fitzhall Heath. In 2007 and 2009, a total of 22 individuals were released on two areas. These areas (known as sites A & B) were created using turf-strippers. They consisted of clusters of scrapes varying from tens of square metres to hundreds of square metres with the majority of the scrapes on the smaller side. When writing a summary of the re-introduction for Natural England in winter 2012/13 it was discovered that our record keeping had not been detailed enough and at best records consisted of single individuals annually often without accurate grid references. The total number and locations of scrapes was also unknown. All scrapes were mapped using a GPS and or aerial photos in ArcGIS. They were measured and aged and this shapefile was to be the basis for an invertebrate survey focusing on Heath Tiger Beetles but also including all other species associated with bare ground. Once a month between May and August the scrapes were visited and all species of invertebrate were recorded and counted where possible. As it was always intended that this project could be passed to a volunteer, an index system was applied to all species so that different levels of ability could tackle different difficulties of species. Only the stillest, hottest and sunniest days were surveyed. Heath Tiger Beetle was found to be abundant and widespread. It was recorded in all four months, peaking in August, where 67 individuals far outnumbered Green Tiger Beetles on any other visit and a maximum of 14 were found on one individual scrape, the original release site A. The species was also widespread, being found on 28 scrapes in all. During August they were also found 200 m away on release site B where none had been seen since their release there in 2009. The species can now be considered well established at Iping Common. A total of 54 species were recorded and 32 of these were thought to be using the scrapes. This included the first site records of the Na BAP carabid Anisodactylus nemorivagus, the first records of the Nb jumping spider Talavera petrensis in Sussex for 45 years and a species of rove beetle Acidota crenata, usually associated with mountains, was new to Sussex. Other. The most widespread species was Green Tiger Beetle and the most abundant species was the nationally scarce wasp Ammophila pubescens. Scarce species not associated with bare ground included Hornet Robber-fly and Dotted Border Wave Analysis of the size and age of scrapes in relation to the species-richness associated with them was made but any conclusions drawn are made with caution as there are many variables at work. The scrapes which seem to provide the greatest biodiversity return are in the 100 m2 to 500 m2 size range and it is thought that by increasing the number of scrapes inside this size range is likely to have a positive impact A site visit in late 2013 used the findings of this survey to place approximate locations for future turf- stripping areas. Some of these areas consolidate the existing areas while others connect them. All are placed about the same distance from the woodland to the south as it is not yet known how important the shelter aspect is. The survey was thought to be a success as the distribution of the Heath Tiger Beetle at Iping is now known as is the presence of some very scarce invertebrates that are also benefiting from the scrapes. An up to date scrape map that can be added to as new scrapes are created underpins the monitoring which means all of the objectives have been met. In addition, some very knowledgeable volunteers have come forward to take on the work which will go through a hand-over with the author in 2014. 3 1 - Introduction 1.1 – Summary taken from ‘Lyons, G. (2013) Heath Tiger Beetle Cicindela sylvatica at Iping Common. Unpublished report to Sussex Wildlife Trust’. Heath Tiger Beetle Cicindela sylvatica is a Na BAP species. The last unsubstantiated records of this species occurred in the Fitzhall Heath area of Iping Common. A re-introduction programme was initiated in 2007 and ended in 2009 and was comprised of 22 individuals. A history of the introduction and consequent records was as follows. See figure 1 below for details: • 2007. Six adults released at site A. • 2009. End of June 2009. No sign of progeny on the release site from the 2007 release. Another 16 adults released in 2009. Ten on the 3rd July 2009 (five each on site A and site B) and six on the 31st July 2009 (three each on site A and site B). Before releasing the three specimens on site A on 31st July 2009, five specimens were recorded in this area using the scrapes (including a mating pair). • 2010. Recorded in the large scrape at site A. rd • 2011. On the 23 June a single specimen was recorded somewhere in the release site A but NOT the larger scrape. • 2012. On the 23rd July a specimen was spotted 75m west of the original release site A and photographed. The specimen was seen to use all three scrapes in a small complex ESE of release site A. As accurate records have not been kept it is not clear when these scrapes were put in but based on the lack of vegetation within them it is the author’s opinion that they were made over the winter of 2011/12 (this has since been proven to be correct). • 2012: invertebrate survey. The author and Andy Phillips carried out an invertebrate survey of Iping Common focused around a grazing trial plot at Iping that encompassed introduction site B and much of the heathland to the north of this area. Despite four visits throughout the field season, no specimens were seen in or near this area. 1.2 – Reasons for monitoring The report (Lyons, 2013) highlighted some gaps in record keeping. • Firstly, a far more robust strategy for mapping and recording scraped areas at Iping is necessary in order to guide where future scrapes should be placed and as a record for the management planning process. • Secondly, better record keeping of Heath Tiger Beetle sightings is required in order to understand how well the re-introduction has gone but also to understand what other invertebrates are using the turf-stripped scrapes. A standardised survey is required so that spatial changes over time can be assessed. 4 Fig. 1. The original release sites and location of recent records with minimum potential range based upon maximum distance of recent records from original release site. 5 2 – Methodologies 2.1 – Mapping, measuring and aging the turf-stripped areas During the early part of 2013, all turf-stripped areas were mapped with a GPS or by plotting them on recent aerial photographs in ArcGIS. With the help of Bruce Middleton and Dan Cornell, the scrapes were all aged and along with the approximate area of the scrape, and an identification number, this information was stored in a single shapefile in ArcGIS that can be both added to and printed on a map to take into the field. 2.2 – Invertebrate survey The primary aim of the survey was to see how successful the reintroduction of Heath Tiger Beetles had been. No structured monitoring had been at all and single records of Heath Tiger Beetles ere often the best that was achieved in most given years. By covering ALL/as many the turf-stripped areas as possible in a single visit was desired over trying to record fewer sites in more detail. It is thought that this method is certainly suitable for monitoring Heath Tiger Beetles and for many larger invertebrates. Although some very small species were detected, they are likely to not have been covered in as much detail as the larger ones. This balance though is thought to be acceptable as the primary reason for doing the work is the Heath Tiger Beetles and therefore searching should be carried out at this scale. Anything additional is a bonus but the list of invertebrates is not thought to be comprehensive. Despite a very cold and late spring, it was not difficult to find suitable days from May onwards. Four visits were made to the site and these were as follows. 1st May, 5th June, 5th July and 1st August 2013. Rather than just work on days that were suitable for surveying invertebrates (i.e. not raining or windy) it was better to carry out the surveys on still, warm and sunny days. i.e., the very best days of the season were used to carry out this survey. This was done to maximise the chances of seeing as many warmth loving invertebrates as possible. Individual scrapes were used as individual sampling units. Many of the scrapes at Iping are small enough for one person to cover in between 30 seconds and a minute.