Priority Ecological Network in the Terrestrial Environment

Priority Ecological Networks (PENs) in the terrestrial environment are versions of the all-Wales habitat networks that show areas of connectivity between Protected Sites, and as such provide a framework to inform the location of action to build functional resilient ecological networks based on our most important places for biodiversity.  Typical actions would be habitat improvement, restoration, or creation, located within the boundaries of a PEN, or situated at its margins to consolidate, extend, or link different PENs. These PENs supersede the GIS layers that were previously known as ‘Level 2 networks’, and are available for:

Native woodland; Semi-natural grassland; Heathland; Bog; Fen and Sand Dune

All these priority networks are also represented as a ‘PEN Hotspot’ map, which is a simple count of all available networks within a given 1km square for an ‘at a glance’ view across Wales.

In addition, the ‘native woodland’ and ‘semi-natural grassland’ PENs have both received updates in the form of additional networks to  accommodate our latest protected sites series and survey information and expand beyond what was originally available. Heathland, Bog and Fen have been merged from their originally separate upland and lowland versions into singular datasets and a previously unreleased ‘sand dune’ network is also now included.  A Freshwater PEN is planned.

Please note: These individual map layers are a modelled description of current connectivity between habitats and as such should be considered as descriptive, rather than prescriptive!

As well as this set of priority networks, it is useful to also be able to view these layers alongside other open datasets available for download from DataMap Wales using the links below:

  • SSSI boundaries:

Sites of Special Scientific Interest (SSSI) | DataMapWales (

  • SSSI boundaries buffered to 300m

WOM21 Site of Special Scientific Interest (SSSI) / Special Area of Conservation (SAC) 100/300m Buffer | DataMapWales (

Priority Ecological Network in the marine environment

At sea, an ecologically coherent network of marine protected areas (MPAs) has been established which, when measures are in place to bring about good condition, will form the marine Resilient Ecological Network.

Connectivity within the MPA Network is inherently good, however some of the features (species and habitats for which the sites are designated) are known to be in unfavourable condition (Natural Resources Wales / Indicative feature condition assessments for European Marine Sites).

The marine Priority Ecological Network (MPEN) map shows the full extent of the MPA network (light blue), highlighting the sites where one or more features are known to be in unfavourable condition (hatched area).

In these hatched areas, action is needed to deliver measures that restore features, reduce pressures to enable their recovery, or gather evidence needed to support effective management.

NRW continues to gather and assess information about the condition of habitats and species across the MPA network.  Future iterations of the MPEN will incorporate new evidence and understanding as it becomes available.

Alongside the MPEN it may be useful to view:

Other useful open datasets available for download from DataMapWales include:

Attribution statement:

Contains Natural Resources Wales information © Natural Resources Wales and Database Right. All rights Reserved. Contains Ordnance Survey Data. Ordnance Survey Licence number AC0000849444. Crown Copyright and Database Right.

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  • nrw_marine_pen_2023

  • nrw_native_woodland_pen_2023

  • nrw_pen_hotspot_2023

  • nrw_semi_natural_grassland_pen_2023

  • nrw_heathland_pen_2023

  • nrw_sand_dune_pen_2023

  • nrw_fen_pen_2023

  • nrw_bog_pen_2023

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