Invertebrate Survey of Moorend Common 2013
Total Page：16
File Type：pdf, Size：1020Kb
Invertebrate Survey of Moorend Common 2013 Lawrence Bee December 2013 Invertebrates of Moorend Common, Buckinghamshire Prepared by Lawrence Bee* With Lane End Conservation Group Client: The Chilterns Conservation Board Part of the Chilterns Commons Project *Lawrence Bee - Ecological and Environmental Education Consultancy 7 Oakmead, Witney, Oxon OX28 1EF 07870854106 email: [email protected] Contents Introduction 1 Objectives 3 Survey methodology 4 Invertebrates recorded 8 Spiders Beetles Centipedes, Millipedes and Woodlice Other Groups Recommendations 11 Acknowledgements 14 References 15 Survey results o Spiders 16 o Beetles 19 o Centipedes, Millipedes and Woodlice 21 o Other Groups 22 Front page: The ground beetle Agonum sexpunctatum – a NotableA species in the UK (see text p.9)©entomart Introduction A view of Middle Meadow at Moorend ©Rob Rowe - Natural England Common National Grid Reference: SU 801 907 (north section) & SU802905 (south section) County: Buckinghamshire Local authority: Wycombe District Council. Parish: Lane End Area: c. 21.58 ha Moorend Common is a Site of Special Scientific Interest (SSSI) notified under Section 28 of the Wildlife and Countryside Act 1981. The full S.S.S.I. citation provided by Natural England is available online at: http://www.sssi.naturalengland.org.uk/citation/citation_photo/1001497.pdf The NE citation for Moorend Common states that, in addition to areas of secondary tree growth, scrub and wetland, the key indicators are U4 acid grassland and W10 and W14 woodland. All are encompassed within the recognised habitat types of either Lowland 1 Heathland and Acid Grassland or Woodland within the Buckinghamshire and Milton Keynes Bio-diversity Action Plan (BAP). U4 Grassland – a habitat composed of a mixture of grasses and herbs which exists on acidic soils or substrates. This grassland type is increasingly rare within the Chilterns and is diminishing as methods of land management have changed away from regular grazing or mowing. W10 Woodland – a habitat composed of oak woodland predominantly on acid soils or substrates. Typical species, in the Moorend Common SSSI, include pedunculate oak and silver birch, an understorey of hazel and hawthorn and a ground flora of bracken and bramble. W14 Woodland – a habitat composed of beech woodland on relatively base poor to acidic soils and substrates. Typical species, in the Moor Copse, include beech and an understorey of holly and bramble with a sparse ground flora owing to the dense shade created by the mature beech canopy. Detailed ecological information can be found within the ‘Heathland’ and ‘Woodland Habitat’ sections of the Buckinghamshire and Milton Keynes BAP of 2000 and the Chilterns Conservation Board’s draft BAP of 2006. (LEPC & MCCC - Surveys Brief 2012-2015/1st draft 2012). 2 Objectives The survey formed part of the Heritage Lottery funded Chilterns Commons Project managed by the Chilterns Conservation Board. The work was part of a larger project which included historical research and ecological studies alongside monitoring conservation practices to determine their effectiveness. The Lane End Parish Council and the Moorend Common Conservation Committee produced a Management Plan in 2012 and within it there is mention of survey work being carried out on butterflies, moths and aquatic macro invertebrates (LEPC & MCCC - Surveys Brief 2012-2015/1st draft 2012). Survey work on other invertebrate groups was planned in 2010 but did not actually occur. The survey reported in this document was designed to address this omission in covering invertebrate groups where little or no records existed. 3 Survey Methodology 4 locations for siting pitfall traps were identified and established on 13 May 2013. Each location comprised 4 separate pitfall traps set at corners of a square metre and it was agreed with the volunteer team that traps would be emptied and reset approximately every 2 weeks through the summer to finish around the beginning of September. For each location captures from the 4 traps would be treated together but divided into separate containers of (1) spiders & harvestmen, (2) beetles, (3) woodlice, centipedes & millipedes and (4) other miscellaneous captures. Lane End Conservation Group Volunteers setting pitfall traps 4 The 4 locations were chosen to represent different habitats and locations within the Moor End Common site as a whole and were sited as follows (see Maps 1 & 2 ): Site A – SU 80179056 – Just off the edge of the northern section of Middle Meadow amongst leaf litter under mature oak Site B – SU 80219049 – Open area of wet grassland within compartment F Site C – SU 80099075 – Open grassland within North meadow Site D – SU 79969062 – Amongst mature oaks adjacent to stream on N edge of compartment B Site A Site B Site C Site D 5 In addition to the pitfall trapping programme a number of yellow pan traps to capture flying insects was supplied to the volunteer team to set up on site when pitfall traps were being emptied and reset. As it turned out, time availability of the volunteer team made the setting and collection of pan traps impractical and none were set by the volunteers. Just one pan trap was set on a collecting visit made on 13 May 2013. Map 1 : Compartment Map of Moorend Common. (LEPC & MCCC - Surveys Brief 2012-2015/1st draft 2012). 6 C D A B Map 2 : Locations of pitfall traps on Moorend Common 7 Invertebrates Recorded Spiders 60 species of spider were recorded during the survey period. As well as the pitfall samples, other surveys were carried out on 18.10.12, 13.5.13, 5.8.13 and 18.9.13 - these consisted primarily of suction sampling sessions with some sweeping of low vegetation and beating of gorse and lower branches of oak. The pitfall samples were, surprisingly, not very productive for spiders and harvestmen. During pitfall sampling at Chimney Meadows Reserve in Oxfordshire between 2005 and 2010 the traps yielded considerably more individual spider specimens with the total number of species being e.g. 57 species recorded from 103 sample sets in 2009. At Moorend, even though the total number of species recorded was similar in 2013 (to that for Chimney Meadows quoted above), over half of these records came from collecting methods other than pitfall sampling. It is difficult to explain why the pitfall traps captured such a low number of arachnids. In conversation with other arachnologists they too had experienced low numbers of arachnids in pitfall surveys they had conducted in 2013. Possible reasons for the low numbers were the very cool temperatures recorded throughout the spring and early summer of 2013. One of the predominant spider families collected from pitfall traps is the Lycosidae. These ground moving wolf spiders tend to reach maturity in the late spring and early summer and cooler than average temperatures during this period may well compromise the successful maturing of young spiders into mature adults. Amongst the spiders recorded the following species is of interest: • The jumping spider Marpissa muscosa. National Status ‘Notable B’: uncommon in Great Britain and thought to occur in between 31 and 100 10km squares of the National Grid. Collected from underneath the bark of a fallen branch in compartment G/South Meadow. The species is recorded throughout south-eastern England with a few scattered records further 8 ©Andy Callow Jumping Spider Marpissa muscosa west and north. In Dorset it is common under flat stones on the tops of dry stone walls but elsewhere it occurs mostly underneath loose bark on trees, on posts and paling fences. Many specimens collected using the suction sampler were immature and therefore impossible to identify down to species (apart from a very few instances of immature specimens having distinctive markings enabling identification to species). These unidentified immatures indicate a richer spider fauna for Moorend which, if further funding were available, could be surveyed in the future. Beetles 41 species of beetle were recorded from the pitfall traps. Of these 22 were ground beetles and in terms of numbers of individual beetles collected were by far the most dominant group. The three commonest species were Pterostichus madidus with 393 specimens, Abax parallelepipedus with 241 specimens and Carabus problematicus with 116 specimens. Of particular interest was the green and bronze ground beetle Agonum sexpunctatum. The national status for this species is ‘Notable A’ - uncommon in Great Britain and thought to occur in 30 or fewer 10km squares of the National Grid. The preferred habitat for this species is ‘On damp open ground near water, on sandy soils in heaths and open woodland’ (Luff 2007) which corresponds well with the location of site B – the 9 only pitfall trap site where it was found. This record caused some excitement when it was identified by Lloyd Garvey at the University Natural History Museum in Oxford where Lloyd was identifying the beetles. Unfortunately, due to prolonged immersion in the propylene glycol solution many of the beetles began to disintegrate and so preserving specimens was not possible. Lloyd did a great job in identifying the material and only had problems distinguishing between 2 very similar species. The entry in the species list for Pterostichus nigrita/rhaeticus is the one record where it was impossible to distinguish between the 2 species – they are only separable by examination of the genitalia and the fragmented state of the specimens made this impossible. Centipedes, Millipedes and Woodlice All but one of the centipede and millipede species recorded from the pitfall traps have the national status of ‘Common’. The exception, the stone centipede Lithobius muticus, has a national status of Notable B and is regarded as scarce nationally. In the Chilterns, however, it is a locally common species, Moorend providing a suitable deciduous woodland habitat. Five species of woodlice were recorded. The Carr Slater Ligidium hypnorum is locally common in the Chilterns but is nationally only found in the south east and south central regions - not being recorded north of a line between the Wash and the Bristol Channel.