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

2. 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

3. 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

4. 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

5. 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.

6. 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

7. 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)

8. 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 ha of Pagham ground surveyed.

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

10. 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

11. 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

12. 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

13. 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

14. 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.

15. 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 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

16. 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

17. 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 Habitats verified by ground-truthing surveys.

18. 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

19. 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

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

21. 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: Fax: