NECR195 Edition 1 a Review of the Status of the Dolichopodidae Flies Of
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Natural England Commissioned Report NECR195 A review of the status of the Dolichopodidae flies of Great Britain Species Status No.30 First published October 2018 www.gov.uk/natural -england Foreword Natural England commission a range of reports from external contractors to provide evidence and advice to assist us in delivering our duties. The views in this report are those of the authors and do not necessarily represent those of Natural England. Background Making good decisions to conserve species This report should be cited as: should primarily be based upon an objective process of determining the degree of threat to DRAKE, C.M. 2018. A review of the status of the the survival of a species. The recognised Dolichopodidae flies of Great Britain - Species international approach to undertaking this is by Status No.30. Natural England Commissioned assigning the species to one of the IUCN threat Reports, Number195. categories. This report was commissioned to update the threat status of Dolichopodid flies last undertaken in 2005, using the IUCN methodology for assessing threat. Reviews for other invertebrate groups will follow. Natural England Project Manager - David Heaver, Senior Invertebrate Specialist [email protected] Contractor - C.M Drake Keywords - Dolichopodidae flies, invertebrates, red list, IUCN, status reviews, IUCN threat categories, GB rarity status Further information This report can be downloaded from the Natural England website: www.gov.uk/government/organisations/natural-england. For information on Natural England publications contact the Natural England Enquiry Service on 0300 060 3900 or e-mail [email protected]. This report is published by Natural England under the Open Government Licence - OGLv3.0 for public sector information. You are encouraged to use, and reuse, information subject to certain conditions. For details of the licence visit Copyright. Natural England photographs are only available for non commercial purposes. If any other information such as maps or data cannot be used commercially this will be made clear within the report. ISBN 978-1-78354-332-8 © Natural England and other parties 2018 Contents 1. Introduction to the Species Status project .......................................................................... 1 2. Introduction to the Dolichopodidae .................................................................................... 2 3. The IUCN threat categories and selection criteria as adapted for Invertebrates in Great Britain ........................................................................................................................................ 5 3.1 Summary of the 2001 Threat Categories..................................................................... 5 3.2 Application of the Guidelines to Invertebrates ................................................................ 7 3.2.1 The two-stage process in relation to developing a Red List ................................ 8 3.2.2 The use of the Near Threatened category ............................................................ 8 4. GB Rarity Status categories and criteria ............................................................................ 9 5. Methods and sources of information in this review ......................................................... 10 5.1 Assessing the Dolichopodidae ....................................................................................... 10 5.2 Sources of data ............................................................................................................... 11 6. Red List of Dolichopodidae .............................................................................................. 13 7. Species listed by IUCN status category ............................................................................ 21 8. Species listed by GB Rarity Status Category ................................................................... 23 9. Criteria used for assigning species to threatened categories (see Annex II for criteria and categories) ................................................................................................................................ 27 10. Format of the species accounts ......................................................................................... 28 11. Acknowledgements .......................................................................................................... 30 12. The data sheets.................................................................................................................. 31 13. References and Further Reading....................................................................................... 94 Appendix 1. All Species reviewed in the Dolichopodidae .................................................... 105 Appendix 2. IUCN Criteria and Categories ........................................................................... 171 Appendix 3. Moderating criteria for NR/NS rarity status...................................................... 174 i 1. Introduction to the Species Status project 1.1 The Species Status project The Species Status project is a recent initiative, providing up-to-date assessments of the threat status of taxa using the internationally accepted Red List guidelines developed by the International Union for Conservation of Nature (IUCN) (IUCN, 2012a; 2012b; IUCN Standards and Petitions Subcommittee, 2013, 2014). It is the successor to the JNCC’s Species Status Assessment project (http://jncc.defra.gov.uk/page-3352) which ended in 2008. This publication is one in a series of reviews to be produced under the auspices of the new project. Under the Species Status project, the UK’s statutory nature conservation agencies, specialist societies and NGOs will initiate, resource and publish Red Lists and other status reviews of selected taxonomic groups for Great Britain which will then be submitted to JNCC for accreditation (http://jncc.defra.gov.uk/page-1773). This means that the UK’s statutory nature conservation agencies and JNCC will be able to publish red lists. All publications will explain the rationale for the assessments made. The approved threat statuses will be entered into the JNCC spreadsheet of species conservation designations (http://jncc.defra.gov.uk/page-3408). 1.2 The status assessments This review adopts the procedures recommended for the regional application of the IUCN threat assessment guidelines which can be viewed at http://cmsdocs.s3.amazonaws.com/keydocuments/Reg_Guidelines_en_web%2Bcover%2Bba ckcover.pdf. Section 3 and Appendix 1 provide further details. This is a two-step process, the first identifying the taxa threatened in the region of interest using information on the status of the taxa of interest in that region (IUCN, 2001), the second amending the assessments where necessary to take into account interaction with populations of the taxon in neighbouring regions (IUCN Standards and Petitions Subcommittee, 2013). In addition, but as a separate exercise, the standard GB system of assessing rarity, based solely on distribution, is used alongside the IUCN system. 1.3 Species status and conservation action Sound decisions about the priority to attach to conservation action for any species should primarily be based upon objective assessments of the degree of threat to the survival of a species. This is conventionally done by assigning the species to one of the IUCN threat categories. However, the assessment of threats to survival should be separate and distinct from the subsequent process of deciding which species require action and what activities and resources should be allocated. The current review period is 1990-2012, though some later records and species new to the UK up to early 2018 have been included where these substantially alter the conservation status position or the description of the extent of the UK fauna. Suggested Review date: 2025 1 2. Introduction to the Dolichopodidae The first account of threatened British Diptera was included in the British Red Data Books: 2. Insects (Shirt, 1987). This listed 827 species of Diptera, including 58 Dolichopodidae (see Table 1) and provided a single data sheet, for Poecilobothrus ducalis. Table 1. Red List Categories for species covered in Shirt, 1987 Family Category 1 Category 2 Category 3 Category 5 Appendix No Endangered Vulnerable Rare Endemic post 1900 records Dolichopodidae 18 15 25 This was followed by the publication of A review of the scarce and threatened flies of Great Britain (Part 1) (Falk, 1991) which gave statuses but not data sheets for 121 species of Dolichopodidae, of which 55 were included in Red Data Book categories (or extinct) (see Table 2), and 66 were Nationally Scarce (Notable). JNCC adopted revised IUCN Guidelines (IUCN 1994) in 1995, which were subsequently updated (IUCN, 2001), making it necessary to revise the status of all species. Table 2. Red List Categories for species covered in Falk, 1991 Family Category 1 Category 2 Category 3 Category K Appendix No Endangered Vulnerable Rare Insufficiently post 1900 Known records (RDBK) Dolichopodidae 13 13 25 2 2 In A review of the scarce and threatened flies of Great Britain. Part 3 . Empidoidea, Falk & Crossley (2005) provided the first comprehensive review of the Dolichopodidae using the IUCN criteria (see Table 3). As well as providing the criteria for threatened or near threatened species, the category of nationally scarce was retained to provide both some historical continuity and to maintain an