Publication Abstract

Recommendations on the use of habitats maps in the planning process and requirements for future planning areas.

R. Coggan

The responsibilities of the Marine Management Organisation (MMO) include the preparation of marine plans for English waters. The aim of marine planning is to ensure a sustainable future for coastal and offshore waters through managing many activities, resources and assets in the marine environment. Following a selection process, the East Inshore and East Offshore areas were selected as the first two marine plan areas. The MMO tasked the Joint Nature Conservation Committee (JNCC) and the Centre for Environment, Fisheries and Aquaculture Science (Cefas) to provide the best available data on seabed habitats in these plan areas. In addition, the MMO sought recommendations on the appropriate use of habitat maps in the planning process, which is the focus of this report.

For the MMO to make effective management decisions it is important to have access to the best available evidence. In absence of highly detailed and consistent seabed habitat maps for the UK Continental Shelf, best available survey derived and modelled habitat maps were produced for the MMO. There are however major limitations using these data layers for effective marine management and this report provides end users such as marine planners or advisors with the necessary background and advice to allow them to make informed decisions using this data.

Habitat maps are most often classified according to the MNCR or EUNIS system. These classifications are human constructs that provide a simplified hierarchical representation of a complex and irregular natural system. Classes at the upper levels discriminate different physical conditions (habitat) whereas those at the lower levels discriminate different faunal communities (biotopes). Although the classification is hierarchical, the current structure is imperfect which leads to inconsistencies between maps generated by top-down (modelling) and bottom-up (survey based) approaches.

Broadscale habitat maps are suited to provide policy guidance and context for management decisions (soft constraints). They provide a generalised indication of the habitats that occur over large areas. Due to the top-down approach, biogenic reefs do not feature in modelled EUNIS Level 3 maps, despite their conservation importance.

Biotope maps derived from survey data are most suited to local decision making and policy development. Their representation of the distribution of biotopes present in an area allows spatially restricted management decisions (hard constraints). The different approaches used to fit nature's complexity into the habitat classification systems often leads to inconsistencies and disjointing where maps meet. These maps provide a snapshot in time and it should be recognised that the seabed is a dynamic environment. Historic habitat maps may therefore not agree when compared to recent evidence.

The outputs delivered as part of this work are presented at EUNIS Level 3 habitats to allow the MMO to undertake a vulnerability assessment using a sensitivity assessment matrix developed for EUNIS Level 3 habitat types. EUNIS Level 3 is internally inconsistent and it is therefore recommended that future work should focus on the development of habitat maps at EUNIS Level 3 for rock and EUNIS Level 4 for sediment abitats.

A confidence assessment is presented with the survey based and modelled habitats maps. Due to the different approaches used to develop these maps, the confidence cannot be compared between them. Similarly, due to the different approach used to map sediments and rock in the modelled habitat map, their confidence cannot be compared. The method of assessing confidence for detailed survey maps simplified to EUNIS Level 3 needs to be revised to account for anomalies caused by that simplification. A good understanding of the process in which the maps were developed is therefore essential.

The lack of robust, area-wide evidence for seabed habitats was demonstrated in this report and forces the need to use predictive modeling approaches to obtain area-wide map coverage. Although it is unlikely that the seabed habitats in other plan areas will be mapped in detail in future, the process to produce best available habitat evidence would benefit from announcing the intended order in which the plan areas will be developed. This would allow time to develop the synthesis of available data or limited targeted survey work to address specific areas of concern or low data density.

Reference:

R. Coggan (2012) Recommendations on the use of habitats maps in the planning process and requirements for future planning areas. A report produced for the Marine Management Organisation, pp 41. MMO Project No: 1014. ISBN: 978-1-909452-03-9 http://www.marinemanagement.org.uk/evidence/documents/1014.pdf