Thanet Coast Special Area of Conservation 2011 Intertidal Monitoring

THANET COAST SPECIAL AREA OF CONSERVATION 2011 INTERTIDAL MONITORING Thanet Coast Special Area of Conservation: 2011 intertidal monitoring. I.Tittley, B. Chapman, B. Hitchin, C.J.H. Spurrier, Kent Wildlife Trust T. Child Thanet Coast Project February 2012 A research report for Natural England Thanet Coast Project c/o Thanet District Council, PO Box 9, Cecil Street, Margate, Kent CT9 1XZ 01843 577672 [email protected] - 1 - CONTENTS 2 EXECUTIVE SUMMARY 3 1 INTRODUCTION 4 1.1 Background 4 1.2 Aims and objectives 5 2 METHODS 6 2.1 Introduction 6 2.2 Fieldwork schedule 7 2.3 Caves and cliffs 7 2.4 Reefs 7 2.5 Study area maps 9 3 RESULTS 15 3.1 Quadrat studies 15 3.2 Revised biotope maps 18 3.3 Climate change indicator species 38 4 DISCUSSION 39 4.1 Cave and cliff biotopes 39 4.2 Foreshore reef biotopes 39 4.3 Important biotopes 39 4.4 Re-classification of littoral cliff and cave biotopes 41 4.5 Climate change indicator species 43 4.6 Non native species 45 5 CONCLUSION 48 5.1 Favourable condition 48 5.2 Future monitoring 48 6 REFERENCES 50 APPENDIX 1 - Study area data 53 Epple Bay (EB) 53 Fulsam Rock (FR) 55 White Ness and Botany Bay (WN) 66 North Foreland (NF) 85 Dumpton and Ramsgate (DG) 97 Pegwell (PB) 109 APPENDIX 2 - List of photographs on DVD 115 APPENDIX 3 - List of algae recorded at Fulsam Rock 116 APPENDIX 4 – Contents of DVD 117 APPENDIX 5 – Point to point biotope surveys 118 - 2 - EXECUTIVE SUMMARY • The results of monitoring ‘reef’ and ‘sea-cave’ features in the Thanet coast cSAC in autumn 2011 are reported. • Study areas monitored in 2001 and 2005 were re-assessed. • Chalk cliff and cave biotopes at the study areas were as previously reported but with the non- native Caulacanthus okamurae present in lower cliff zones. • Foreshore reef biotopes at the study areas were largely as previously reported, but with some potentially significant changes resulting from non-native species. • Revised biotope maps for the six detailed study areas are presented. • Of the 35 biotopes recorded in 1997, the 15 most common were re-assessed in 2001 and 2005 (the remainder fell outside the study quadrat locations). • The important biotope ‘Kelp-dominated communities on animal-bored rock’ was present in most study locations and remained widespread in the Thanet coast cSAC; constituent species were largely as recorded in 2001 and 2005. • Of the seven important biotopes encompassing ‘red-algal turf communities’, two were not examined in the present study because they fell outside the study areas, and three were re- assessed at single study areas only. • The targets for ‘favourable condition’ status have mostly been met despite local impacting of sites and biotopes by non-native species which may increase in future. • Non-native algal and animal species (e.g. Sargassum muticum , Crassostrea gigas ) were more abundantly present in 2011 than in 2005, and Caulacanthus okamurae was found for the first time in this suite of SAC monitoring surveys. The impact of non-native species is reviewed in more detail, particularly in relation to alteration in main biotope features. • Although none of the climate change indicator species on the list were detected, comments are made on the occurrences some of the species likely to increase in abundance. The red algae Spyridia filamentosa and Griffithsia devoniensis (western species not previously recorded as far east as Kent) have been recorded in Thanet (in 2004 and 2011 respectively). Gibbula umbilicalis has become established since the 2005 survey. • Recommendations for future monitoring are made. - 3 - 1 INTRODUCTION 1.1 Background The Isle of Thanet, a small peninsula and outcrop of chalk rock at the extreme east of Kent (Figure 1), has a coastline characterised by a geomorphological structure in which subaerial and marine erosion creates a vertical rocky cliff face that abuts a horizontal wave-eroded platform. The coast of Thanet holds Site of Special Scientific Interest (SSSI), Special Protection Area (SPA) and Ramsar status, as well as Special Area of Conservation (SAC). The qualifying features of interest under the Habitats Directive are the submerged or partly submerged chalk sea-caves and reefs (Brown et al ., 1997; Tittley et al., 1998a; see also www.jncc.gov.uk/Protected.sites/SACselection/habitat/ ). Reefs include ‘submarine, or exposed at low tide, rocky substrates and biogenic concretions, which arise from the sea floor in the sublittoral zone but may extend into the littoral zone where there is an uninterrupted zonation of plant and animal communities’. In the present case the reef is a chalk wave-cut platform. A ‘Habitat Action Plan’ for chalk shores was prepared (Anon, 2000) as part of the United Kingdom ‘Biodiversity Action Plan’ (BAP). In 2001, English Nature produced a management scheme (see below) through a stakeholder process. Since then, the ‘Thanet Coastal Project’ was established, and with stakeholders, has prepared guidelines to coastal activities that aim at protecting coastal habitats and biodiversity (Anon., 2005a). A comprehensive survey of chalk cave, cliff, intertidal and subtidal reef biotopes of the Thanet coast SAC was undertaken in 1997 (Tittley et al. , 1998). This study has provided much of the baseline information for monitoring the marine biotopes and associated fauna and flora at sites along the 23km stretch of coast. Fowler & Tittley (1993) reviewed the importance of coastal chalk cave and cliff habitats in Britain. Their extent in Thanet was described and mapped by Tittley (1985) and this provides an important baseline for comparison. The structure and composition of the associated algal communities was analysed by Tittley & Shaw (1980). Since 1997 additional coastal biotope mapping has been undertaken in the Thanet coast cSAC between Walpole Bay and Foreness Point (Anon., 1998). An appraisal in 2004 looked at the occurrence and impact of the non-native alga Sargassum muticum in Thanet (Vahid, 2004). More recently, studies have been undertaken on the impact of non-native species with particular emphasis on Crassostrea gigas (McKnight, 2009 and 2011). In addition to the present series of monitoring studies, marine biodiversity information for the Thanet SAC can be found in Tittley & Peckham (2004), Rogers (2005), and electronically via the NBN Gateway (www.searchnbn.net/siteinfo/site Data.jsp ) and the Kent Environmental Information Database (KEID) (http://www.kmbrc.org.uk/enquiries/keid/aboutkeid.php ) Natural England has a duty to monitor and assess the condition of the reef and cave features in order to report their conservation status. Natural England ’s advice as to the conservation objectives, and objectives which may cause deterioration of natural habitats or the habitats of species, or disturbance of species for the North East Kent European Marine Sites (which includes the Thanet coast SAC) has been prepared (Anon., 1999). This fulfils its obligations under Regulation 33(2) of the Conservation (Natural Habitats, &c) Regulations 1994. A management scheme for the North East Kent European marine sites was prepared (Anon., 2001, summarised in Anon., 2005b), and the actions were reviewed and updated in 2007. The conservation objectives for the reefs and caves of the Thanet coast cSAC are: • subject to natural change, maintain the reefs in favourable condition, in particular, intertidal chalk cliff algal communities and lichen communities, intertidal red algal turf communities, kelp dominated communities on animal bored rock; • subject to natural change, maintain the submerged or partially submerged sea caves in favourable condition, in particular, intertidal chalk cliff algal and lichen communities. - 4 - A first re-evaluation of the condition of the reefs and caves in the Thanet coast SAC was undertaken in September 2001 (Tittley et al ., 2004, based on a report submitted in 2001); sites monitored in 1997 were re- assessed and additional monitoring sites were set up and studied. Overall the study revealed little significant change and the targets for ‘favourable condition’ status were met. A second re-evaluation was undertaken in 2005 that again confirmed ‘favourable condition’ status but drew attention to the impact of non-native species. Two in particular, the brown alga Sargassum muticum and the Pacific Oyster Crassostrea gigas , had caused changes to the biotopes in the SAC with the potential for changing the features of the intertidal reef of importance for the SAC. Since the last report field studies have revealed that both Sargassum muticum and Crassostrea gigas have become more abundant and extensive in the SAC. The spread and abundance of C. gigas was of such concern that a suite of studies was undertaken to assess its occurrence, distribution and abundance and trial possible means of controlling the species in the SAC and North East Kent Marine Sites area. (McKnight, pers. comm.). Since the 2005 survey, Kent Wildlife Trust’s ‘Shoresearch’ programme has undertaken many field surveys in the SAC. These have contributed many new species records, undertaken the mapping of biotopes using a different approach from that used in SAC monitoring (Tittley et al . 2008), and confirmed rossworm (Sabellaria spinulosa ) reefs at Birchington, a habitat feature of conservation importance, which contributed to the Thanet Coast being included in the Balanced Seas’ suite of recommended Marine Conservation Zones (MCZs) (Anon., 2011). 1.2 Aims and Objectives The aim of this study, as in the 2001 and 2005 surveys, is to monitor and assess the condition of the

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