Fig 1.
Relationship between heathland patch area (ha) and woody succession (both axes log10 transformed).
Woody succession was measured as the proportional increase in area of woody vegetation (with a minimum increase of 1 ha) in each of 110 heathland fragments, derived from the Dorset heathland survey data, for the following intervals: a) 1978–87, b) 1987–96 and c) 1996–2005. Statistical significance of linear regressions indicated as *** P < 0.001, in each case. R2 indicates regression coefficients.
Fig 2.
Relative value of four different vegetation types, situated along a successional gradient, for biodiversity and provision of ecosystem services.
(a) Biodiversity value, presented as the mean number of records per hectare of species of conservation concern, (b) carbon density, presented as mean values of total (above- and below-ground) carbon storage per unit area (t C ha-1), (c) aesthetic value, presented as mean preference scores elicited from a visitor survey, and (d) recreational value, presented as the results of a correlation test between the number of heathland visitors and area of vegetation type (n.s., not significant; * P< 0.05, *** P< 0.001; y axis represents correlation coefficient). For (a)-(c), mean values grouped by the same letter are not significantly different (P< 0.05, Mann Whitney U test). For timber value, see text.
Fig 3.
Relative value of different heathland fragment sizes for biodiversity and provision of ecosystem services.
(a) Biodiversity value, (b) carbon density, (c) aesthetic value, (d) recreation value, and (e) timber value. Heathland fragments were divided into three size categories: small (<50 ha), medium (50–300 ha) and large (>300 ha). The values presented were produced by multiplying the proportion of heathland area comprising the different vegetation types, by the values per unit area of each type (see Fig 2). Values presented are means; those heathland sizes grouped by the same letter are not significantly different (P< 0.05, Mann Whitney U test conducted on median values).