Figure 3b from: Groom Q, Durkin J, O'Reilly J, Mclay A, Richards A, Angel J, Horsley A, Rogers M, Young G (2015) A benchmark survey of the common plants of South Northumberland and Durham, United Kingdom. Biodiversity Data Journal 3: e7318. https://doi.org/10.3897/BDJ.3.e7318

Figure 3b - Interpolated abundance estimates of Calluna vulgaris in South Northumberland and Durham using kriging. The method is described in Bivand et al. 2008, Groom 2013, however the DAFOR score is converted to a numeric value for kriging, zero is used for non-detections and one to five for rare, occasional, frequent, abundant and dominant, rather than using only presence or absence. The vice county boundary data is public sector information licensed under the Open Government Licence v3.0. The kriging variances of the interpolated DAFOR scores