Detailed habitat mapping

 

Downloadable resourcesSPOT image

Making Earth Observation Work

Phase 1

 

Phase 2

Report (High Resolution, 19,047kb)
Report (Low Resolution, 7,565kb)

The following flow diagrams show how the rulebases work in separating out features in the landscape:

General surface rules flowchart

Natural environment rules flowchart

Coast rules flowchart


Phase 3

Defra Science and Research project: Cost effective methods to measure extent and condition of habitats: Earth Observation Phase 3

Surveillance is crucial to provide a broad picture of the extent, location and condition of semi-natural habitats across the UK. This knowledge is necessary to acquire sufficient knowledge about specific species and habitats of conservation concern to enable their protection and the meeting of legislative obligations such as the EC Habitats Directive.

This project constitutes Phase 3 of a wider project to address the role of EO data in habitat monitoring and surveillance needs in the UK, and comprised a number of tasks:

  • further technical and applications development, in an upland environment (the focus of
    previous work was essentially in lowland landscapes and habitats);
  • developing inputs for a business case – identifying users and uses, setting out the
    rationale for adoption and rollout of EO habitat mapping across the UK and
    demonstrating cost-effectiveness of the approach through the example of Habitats
    Directive (Article 17) reporting of Annex I habitats;
  • providing coordination and information exchange with others in the EO and conservation
    sector.

 

Review and scoping of Earth Observation potential

JNCC and DEFRA have been working together on a project called Making Earth Observation Work for UK Biodiversity (MEOW), which has so far included two phases. The aim of Phase 1 of this project was to review recent activity, and report on the potential of using Earth Observation (EO) techniques for biodiversity surveillance of terrestrial and freshwater habitats. During the review and consultations it became clear that current habitat classification systems are not necessarily suitable for describing habitats using EO methods alone.  A “one-size-fits-all” approach will not deliver information on any habitat measure for the full range of higher priority habitats.  There is also a wide variation in the use, knowledge and capacity of organisations to adopt the range of EO techniques currently available or under development.  Overall, surveillance and monitoring needs are going to require a range of techniques tailored to the particular habitats, the features of interest, and size of the area under surveillance.
 
The review concluded that many of the EO based techniques are effective for filling gaps in mapping the location and extent of a range of habitats including those with dynamic environments.  They were also highly cost-effective in comparison to field survey methods and manual EO interpretation, over significant areas.  EO techniques would also contribute to effective targeting of field survey for habitats that will continue to require field survey for their identification.  The report summarises the current use of such techniques by UK country conservation agencies and made a range of recommendations for future actions to promote best practice and facilitate uptake of the most promising techniques.  The project also proposed the Crick Framework, grouping habitats based on the ability of EO and ancillary data to accurately map them.
 

Developing new methods and the Crick Framework approach

The main objective of Phase 2 of MEOW was to undertake a pilot project within Norfolk to test the Crick Framework approach for applied use of EO for operational habitat surveillance and monitoring.  The detailed content of the Crick Framework was also independently peer reviewed.  
 
The pilot used a range of EO techniques, including data from Landsat and DMC (Disaster Monitoring Constellation - 30m pixel size) through to SPOT (Satellite Pour l'Observation de la Terre - 10m), RapidEye (6.5m) and GeoEye-1 (1.65m) satellites, as well as colour infra-red air photography (0.5m).  It also incorporated data captured using a Remotely Piloted Aerial System (RPAS), which allows for repeatable, high-resolution multi-spectral data, aerial photography and detailed surface model data to be captured at time critical points.
 
Using these EO techniques, the pilot tested the transferability of existing methods within Norfolk, examining which BAP Priority and Annex 1 habitats can be found and where the approaches are repeatable.  These methods work by creating a rulebase that combines various data.  Three rulebases were generated in this work; two of them start from attributes within Ordnance Survey data and a third was created specifically for the coastal areas.  Flow diagrams describing these rulebases are downloadable below.
 
Identification of habitats from EO Imagery requires two sorts of knowledge:
 
  • Ecological knowledge about the habitats of interest, including how they appear from above, and their characteristics in the different spectral bands available.
  • Understanding and ability to manipulate the digital remote sensing data within a system, to find the communities and to separate them out from the rest of the landscape.
The findings from the pilot study were used to produce a detailed Crick Framework spreadsheet that provides, for each Biodiversity Action Plan (BAP) Priority and Annex 1 habitat, a detailed habitat description and the relevant EO methods and ancillary data requirements. The Phase 2 final report can be downloaded above. Phase 3 is currently underway, looking at mapping upland habitats.
 

Using EO to Assess Habitat Condition

Maintaining and enhancing the ecological condition of semi-natural habitats and avoiding their loss or deterioration, is vital to maintaining ecosystem services. Monitoring the ecological condition of habitats is a time consuming process using standard field techniques.  The pilot tested the use of EO techniques to measure four habitat conditions: vegetation productivity, single species stands of negative and positive indicators, wetness/dryness and freshwater metrics.
 
Table 1 summarises the measurements used for each of the four habitat conditions and their associated pilot results.  These findings are an initial analysis into the potential of EO as a monitoring tool for habitat condition and more detail can be found in the Phase 2 report.  More work will be necessary to develop these into robust techniques.
 
 
Table 1. Habitat condition, measurement and result from Norfolk pilot.
Habitat Condition
Measurement
Pilot result
Vegetation productivity
  • Normalised Difference Vegetation Index (NDVI)
Productivity maps were produced at a range of scales that allowed visualisation and quantification of the nutrient balance within and around sites.
Single species stands of negative and positive indicators
  • Purple moor-grass (Molinia caerulea);
  • Nettles (Urtica dioica);
  • Gorse scrub (Ulex sp);
  • Birch scrub (Betula sp);
  • Himalayan balsam (Impatiens glandulifera).
The extent of a range of competitive and invasive plant species that can be damaging to sites was classified successfully with a range of types of EO.
Wetness/dryness
  • Normalised Difference Wetness Index (NDWI);
  • Modified Normalised Difference Wetness Index (MNDWI).
Use of a NDWI allowed mires to be classified into a number of wetness categories.  Use of a MNDWI was found to have the potential to identify wet and
dry woodlands.
Freshwater metrics
  • Chlorophyll-A concentrations;
  • Total Suspended Solids (TSS).
A preliminary investigation showed Rapid Eye imagery measured and mapped the eutrophic nature and TSS of water bodies.