Scottish Natural Heritage Archive Report No. 175 LACON: Lake Assessment for Conservation Version 1 Manual ARCHIVE REPORT Archive Report No. 175 LACON: Lake Assessment for Conservation Version 1 Manual For further information on this report please contact: Alison Lee Scottish Natural Heritage Silvan House 231 Corstorphine Road EDINBURGH EH12 7AT Telephone: 0131 316 2620 E-mail: [email protected] This report should be quoted as: Palmer, M.A. 2008. LACON: Lake Assessment for Conservation – Version 1 Manual. Scottish Natural Heritage Archive Report No. 175. This report, or any part of it, should not be reproduced without the permission of Scottish Natural Heritage. This permission will not be withheld unreasonably. The views expressed by the author(s) of this report should not be taken as the views and policies of Scottish Natural Heritage. © Scottish Natural Heritage 2019. 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LACON: LAKE ASSESSMENT FOR CONSERVATION CONTENTS Page SUMMARY iv ACKNOWLEDGEMENTS v INTRODUCTION 1 Background 1 Data requirements 2 The LACON evaluation system 2 Testing the LACON scoring system 5 Interpretation of the output 5 Possible future work 7 CONSERVATION CRITERIA 8 PHYSICAL DIVERSITY 8 Concept of Physical Diversity 8 Calculation of Physical Diversity Index 9 PDY 1. Littoral substrates 9 Table PDY 1. Littoral substrate types found in lakes 9 PDY 2. Structure of aquatic vegetation 10 Table PDY 2. Growth form categories of standing water vegetation 10 PDY 3. Other habitat features 11 Table PDY 3. Other habitat features of lakes 11 NATURALNESS 12 Concept of Naturalness 12 Calculation of Naturalness Index 13 NA 1. Physical features 14 NA 2. Aquatic macrophytes 15 Table NA 2.1. Alien aquatic vascular plants established in standing waters in Great Britain 16 Table NA 2.2. Aquatic vascular plants native to Great Britain but not to Scotland, established in standing waters in Scotland 17 Table NA 2.3. Standing water vascular plants native to Great Britain that are restricted in natural distribution, but are introduced elsewhere 17 NA 3. Adjacent habitat 18 Table NA 3. Natural and artificial Phase 1 Habitat Survey categories 19 REPRESENTATIVENESS 20 Concept of Representativeness 20 Calculation of Representativeness Index 22 RE 1. Aquatic macrophyte complement 23 i Table RE 1. Most typical submerged and floating macrophyte taxa in Lake Groups 24 RE 2. Plant Lake Ecotype Index ( PLEX) 26 Table RE 2.1. PLEX scores for submerged and floating macrophytes 27 Figure RE 2. Range of PLEX scores for Lake Groups 29 Table RE 2.2. Range of PLEX scores for Lake Groups 29 RARITY 30 Concept of Rarity 30 Calculation of Rarity Index 34 RA 1. Bern Convention / Habitats Directive plant species 35 Table RA 1. Standing water plant species native to the UK listed in Appendix I of the Bern Convention and Annexes IIb and IVb of the Habitats Directive 35 RA 2. Scheduled plant species 36 Table RA 2. Standing water vascular plant and charophyte species included in Schedule 8 of the Wildlife and Countryside Act 1981 and protected under the Nature Conservation (Scotland) Act 2004 36 RA 3. Red List plants 38 Table RA 3. Standing water vascular plants and charophytes included in British Red Lists 39 RA 4. Habitats Directive Annex IIb plant species common in the UK 41 RA 5. Near Threatened, Nationally Rare and UK Biodiversity Action Plan priority plant species 41 Table RA 5. Standing water vascular plant and charophyte species that are Near Threatened, Nationally Rare or UK Biodiversity Action Plan priority 42 RA 6. Nationally Scarce plant species 43 Table RA 6. Standing water vascular plant, charophyte and liverwort species that are Nationally Scarce 44 RA 7. Plant species for which Britain has International Responsibility 45 Table RA 7. Standing water plants for which Britain has International Responsibility 45 RA 8. Plant species Uncommon in England, Scotland or Wales 46 Table RA 8.1. Standing water plant species Uncommon in England 47 Table RA 8.2. Standing water plant species Uncommon in Scotland 48 Table RA 8.3. Standing water plant species Uncommon in Wales 49 RA 9. Regionally Uncommon plant species 50 Table RA 9.1 Regionally Uncommon standing water plant species: Environment Agency Regions 52 Table RA 9.2. Regionally Uncommon standing water plant species: Scottish Environment Protection Agency (SEPA) Areas 53 ii SPECIES RICHNESS 54 Concept of Species Richness 54 Calculation of Species Richness Index 54 SR 1. Aquatic macrophytes 56 Table SR 1. Checklist of native aquatic macrophytes of standing water 57 SR 2. Marginal vegetation communities 63 Table SR 2. National Vegetation Classification swamp and tall-herb fen communities associated with standing water 64 IMPACTS 65 Quantifying impacts 65 Calculation of Impacts Index 66 IM 1. Acidification 68 IM 2. Eutrophication 68 IM 3. Water abstraction and water level management 69 IM 4. Recreational, educational and/or military pressures 69 IM 5. Introduced species 70 IM 6. Surrounding land use 70 IM 7. Modification of lake morphology 71 ADDITIONAL FEATURES OF IMPORTANCE (AFIs) 72 Concept of Additional Features of Importance 72 Table AFI 1. Additional Features of Importance 72 Table AFI 1.1 Some established alien vascular plants of wetlands and water margins 78 REFERENCES 79 ANNEX 1 The standard loch survey method 82 ANNEX 2 Results of tests on the LACON scoring system 83 ANNEX 3 Maps showing the distribution of Lake Groups A to J in Britain 93 ANNEX 4 Key to Lake Groups 104 ANNEX 5 Constancy table for Lake Groups: submerged and floating vegetation 106 ANNEX 6 Rarity status of standing water plants in Britain 107 ANNEX 7 Maps of Environment Agency Regions and Scottish Environment Protection Agency (SEPA) Areas 118 iii SUMMARY LACON (Lake Assessment for Conservation) is a semi-quantitative method of assessing the nature conservation interest and value of standing waters in Great Britain. It is modelled on SERCON (System for Evaluating Rivers for Conservation), which was developed by the UK statutory nature conservation agencies, in conjunction with a number of other bodies, for the assessment of river conservation value. LACON is based on the most important and well-used of the 'classic' nature conservation evaluation criteria: naturalness, representativeness (typicalness), rarity and diversity. LACON elaborates this approach by using a range of attributes under each criterion and applying a scoring system to achieve rigour and repeatability in the assessment. Thus, the value of a site for a particular criterion is quantified in relation to that of other sites. LACON also attempts to quantify the impact of human activity on a water body. A comprehensive 'library' of reference data, on which the scoring is based, is incorporated in this manual. Since the mid 1970s, the British statutory nature conservation agencies have carried out botanical surveys of approximately 3500 standing waters throughout England, Scotland and Wales. These water bodies include lochs, lakes, meres, ponds, pools, lagoons, reservoirs and gravel pits. Most are fresh waters; a few are slightly saline. The data from these surveys are now incorporated in a computerised database held by the Joint Nature Conservation Committee (JNCC). LACON is a tool for assessing the nature conservation value of these and other lakes, using data collected in a standard manner. This manual deals mainly with habitat features and aquatic and marginal plant communities. It is hoped that other taxonomic groups might be more fully incorporated into LACON in the future. iv ACKNOWLEDGEMENTS Thanks are due to Chris Preston and Henry Arnold, of the Biological Records Centre, CEH Monks Wood, for drawing up preliminary checklists of plants in Water Authority regions and SEPA areas. Phil Boon and Mary Hennessy, of Scottish Natural Heritage, commented on drafts of this manual. Nigel Holmes and Phil Boon provided invaluable insights into the intricacies of SERCON. The Joint Nature Conservation Committee (JNCC) gave permission for the use of distribution maps of Lake Groups (Annex 3) and other information from the lake classification work (Annexes 4 to 5). The Scottish Environment Protection Agency provided the map of SEPA areas (Annex 7). v INTRODUCTION Background LACON (Lake Assessment for Conservation) is a method of assessing the nature conservation value of standing waters.