Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat General introduction Mark Lang, Christopher Blair-Myers, Bruce Lascelles Hyder Consulting

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Presentation overview Overview of the Integrated Habitat System (IHS) South East Strategic Regional Coastal Monitoring Programme Project aims and objectives Methodology Change – habitat change, boundary change Field survey verification Results from Pagham Harbour

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat The Integrated Habitat System (IHS) IHS was developed by the Somerset Environmental Records Centre (SERC) Integrates Biodiversity Habitat Types with Annex 1 Habitats Directive. A hierarchical system of classification LEVEL 1: LS3 – Coastal salt marsh LEVEL 2: LS32 – Spartina swards LEVEL 3: LS321 – Spartina maritima swards Priority habitats form the basis of the Natura 2000 system SAC in the UK Conventional classifications, Phase 1 and NVC don’t really address these habitat types - this system used to map coastal BAP habitats

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat South East Strategic Regional Coastal Monitoring Programme (SESRCMP) 2006 Mapping (through BRANCH project): Coast from Isle of Grain to Christchurch Harbour mapped Aerial Photograph Interpretation (API) from 2005 flown photos Other datasets such as County Phase 1 data also used to supplement and inform the API process

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat South East Strategic Regional Coastal Monitoring Programme (SESRCMP) 2009: Review SESRCMP 2006 habitat mapping data in relation to 2008 aerial photographs Rectify in order that errors are not propagated Mapping to be produced to IHS Level 1 and where possible to Levels 2-4 Undertake field survey in sample areas focusing on habitats that cannot be classified solely by API Quantify habitat change between 2005 (aerials on which 2006 mapping based) and 2008 Quality Assure all data and correct as appropriate Survey area Isle of Grain, Kent to Christchurch Harbour Dorset Hyder Consulting engaged by the Environment Agency (EA) to review habitat data mapped in 2006 overlain on 2008 aerials. Interpret aerial photographs for the survey area assign the habitats to one of 18 categories defined by the IHS. The habitat parcels identified will then be digitised using GIS to produce a series of shape files using a different layer for each of the BAP habitats. Where possible the survey work would attempt to quantify habitat change by comparing habitat data between 2006 and 2008, with particular focus on thos habitats which cannot be classified solely by API.

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Methodology Stage 1 Aerial Photograph Interpretation Review of the 2006 habitat mapping data (and 2005 aerial photographs where available) against the 2008 aerial photographs Potential habitat change (type and extent) and mapping errors identified and flagged Once the review of each ‘Project’ completed, those polygons flagged revisited to confirm changes required Stage 2 API Changes noted in Stage 1 made Differentiation in the database of whether the change related to the classification or the habitat (polygon) boundary, or both

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Methodology Stage 3 Field Surveys (Ground Truthing) Large scale maps showing the 2006 habitat mapping used Binoculars used to identify habitat where access not possible Verification that the habitat types present in 2006 are still present in 2008, are mapped in the correct location and with the correct extent Included some areas in the Regional Habitat Creation Programme (RHCP) Maps marked up with amendments as required Changes to boundaries or habitat classifications made as for Stage 2 (i.e. updated geodatabase)

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat 2006 Pagham representative of survey area and most of it has been surveyed in the field 488.95ha of Pagham ground surveyed.

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat 2009 Pagham 2008 Little apparent change

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Pagham well mapped to Level 1 Some mis-maping of saltmarsh sub-communities but they are broadly similar The increase in both the area of saltmarsh due to more accurate mapping and mapping of new saltmarsh accretions and mudflat are probably due to more accurate mapping of intertidal shingle and mudflat and overlapping polygons outside of the cut off for Pagham harbour Sea wall grassland assigned (GN6 rather than GNZ previously) These figures relate to pagham and may not be representative of whole project area

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Relatively little change required with field survey confirming accuracy of data Again, it’s worth noting that these figures relate to Pagham Harbour and may not be representative of whole project area

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Least confident about habitat change although would consider changes in vegetation communities will be limited over a three year period Where we have made a habitat change to a polygon we can in some instances be sure its real change (e.g. we have created a new polygon or habitat lost to development) Comparison with the 2005 aerials gives some indication if change is a result of mapping error For the majority it is not known if the habitat change is real change, mapping error, error in supplementary data used in the 2006 mapping project or other factors

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat We can be more confident that boundary change is a result of real change by direct comparison with the 2005 aerials Primarily relates to salt marsh erosion or accretion and movements of sediment dominated habitats

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Of the polygons where both classification and boundary change have been made, the large proportion were a result of real change. No specific mapping errors were identified in relation to these.

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Example of real habitat change within Pagham Harbour. LS32: Spartina swards LS31: Salicornia and other annuals colonising mud and sand LS32 increased substantially, with less LS4 than previously plotted. Extent of salt marsh habitat in 2006 as mapped on 2008 aerial Increase in salt marsh habitat in 2009 as mapped on 2008 aerial LS32 (Spartina swards) appears to have increased substantially, with less LS4 (intertidal mudflat) than previously mapped

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Example of an area of correctly mapped salt marsh. LS332 Puccinellia maritima mid-marsh LS37 Elytrigia atherica upper-marsh LS333 Atriplex portulacoides mid-marsh LS32 Spartina swards Example of where 2006 mapping correct. Mapping verified through ground survey. Mapping of boundaries very accurate

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat An area of salt-marsh that was mis-mapped in 2006 LS333: Atriplex portulacoides mid-marsh LS32: Spartina swards [Cord grass] WB34: Wet woodland LS341: Festuca rubra upper salt-marsh LS343: Juncus maritimus-Triglochin maritima salt-marsh Short distance from previous example showing where mapping not correct Not known if this change a result of real change or mapping error, however derived Habitats as mapped in 2006. Habitats as mapped in 2009. Habitats verified by ground-truthing surveys.

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Initial findings Habitat appears to have been accurately mapped in 2006 Some mis-classification of sub-communities revealing limitations to the API process Changes made to polygon boundaries - most likely due to real change Changes to habitat classification - in most cases the cause is unknown Habitats dominated by sediment highly mobile and subject to rapid change To add that generally very good and where it is not its due to limitations in the process so broad habitat very accurate but not always sub community level

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Timescales Project completion date: 5th March 2010 Following QA checks, data will be published on the Channel Coast Observatory Website QA checks refer to EA checks post-submission

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat Acknowledgements Somerset Environmental Records Centre Christopher Blair-Myers Hyder Environment Environment Agency

Pagham Harbour – Distribution & Changes in Extent of Coastal BAP Habitat For further information contact: Hannah Gribben Technical Specialist, Strategic and Development Planning Environmental Agency (Southern Region) Guildbourne House Chatsworth Road Worthing West Sussex BN11 1LD Tel: 01903 832095 Fax: 01903 832278 Email: hannah.gribben@environment-agency.gov.uk