Historical Kelp Forest Distribution Along British Columbia Coast 1858-1956

137 British Admiralty charts from 1858 to 1956 were scanned and georeferenced to map kelp presence. The dataset covers the BC coast, extending to portions of Washington and Alaska, and digitizes kelp features as polygons representing presence. It focuses on two canopy-forming species, bull kelp (Nereocystis leutkeana) and giant kelp (Macrocystis pyrifera).

Use Cases

• Analyze spatiotemporal changes in kelp presence using digitized polygon features and associated survey start and end year attributes.
• Model historical kelp distribution relative to coastal features using georeferenced polygon locations and chart scale data.
• Assess the reliability of historical kelp observations by examining the location accuracy criterion linked to local depth.
• Correlate historical kelp presence from chart-derived polygons with modern environmental drivers like sea temperature change.

Strengths

• Based on 137 original British Admiralty charts, providing a substantial historical baseline.
• Covers a long temporal range from 1858 to 1956, enabling century-scale trend analysis.
• Implements a defined reliability criterion for digitized kelp feature location accuracy.
• Polygon features include chart metadata attributes like scale, chart number, title, and survey years.

Limitations

• Polygons represent kelp presence, not area or biomass, limiting quantitative density analysis.
• Data is historical (up to 1956) and may not reflect current conditions without modern complementary datasets.
• Spatial accuracy is dependent on the original chart scales, which range from 1:6,080 to 1:500,000.

Provenance

Source

Fisheries and Oceans Canada

Collection Method

Digitized from 137 scanned and georeferenced British Admiralty charts using ESRI ArcMap, with validation against satellite imagery and other hydrographic sources.

Time Range

1858 to 1956

Freshness

null

Geography

Coast of British Columbia, Canada, extending to portions of Washington and Alaska coasts.