Repeatability of Phase 1 habitat survey

Area of Science:

• Ecology
• Environmental Science
• Conservation Biology

Background:

• The Habitat Survey of Wales extensively mapped land cover using the Phase 1 method between 1987 and 1997.
• Concerns regarding data consistency in Phase 1 habitat mapping, particularly between different organizations, have been raised in recent studies.

Purpose of the Study:

• To audit the quality and consistency of habitat mapping data collected during the Habitat Survey of Wales.
• To assess the repeatability of Phase 1 habitat mapping within a single organization.

Main Methods:

• A resurvey of 294 randomly selected points from the original Habitat Survey of Wales was conducted.
• Habitat mapping data from an initial 'surveyor' was compared against an 'assessor' to determine correspondence levels.

Main Results:

• Overall repeatability of Phase 1 habitat mapping within the organization was estimated at 83%, increasing to 85% when habitats were grouped.
• Repeatability varied by habitat type, with highest correspondence for modified land cover (88%) and lowest for semi-improved types (56%).
• Discrepancies were primarily due to habitat identification differences, often on transitional or borderline vegetation.

Conclusions:

• The Phase 1 habitat mapping within the organization demonstrated a high level of repeatability, exceeding figures reported in inter-organizational consistency studies.
• Recommendations were developed to further improve the consistency and accuracy of future habitat mapping efforts.
• The findings suggest that Phase 1 mapping can yield reliable data when applied consistently within a single organization.