1. Growth-stage optimisation (GSO) offers a new approach to biodiversity conservation in fire-prone regions through estimating the optimal distribution of vegetation growth stages that maximises a species diversity index. This optimal growth-stage structure provides managers an operational goal explicitly linked to a positive conservation outcome but does not define the fire regime needed to achieve it. 2. We paired GSO with LANDIS II, a landscape succession and disturbance simulation model, to (1) estimate the optimal growth-stage structure that maximised vegetation diversity in a south-east Australian heathy woodland, (2) define the fire regime needed to achieve it, and (3) determine the cumulative effects of different fire-regime scenarios on vegetation diversity over a 60-year period. Scenarios included 0, 2, 5 and 10% of the landscape burnt per year by prescribed fire only, or in combination with three alternative wildfire regimes. In addition, we investigated the differences in the optimal growth-stage structure relating to above-ground, soil seedbank, and total (above and soil seedbank) diversity data sets. 3.The growth-stage structure that maximised total vegetation diversity comprised approximately even proportions of all stages. In contrast, separately analysed above-ground and soil seedbank data resulted in a greater proportion of younger and older growth-stages, respectively. 4. Scenarios including 5% prescribed burning per year (with and without wildfire) resulted in diversity values within 1.5% of the theoretical maximum value. Scenarios including 2% and 10% prescribed fire resulted in diversity values 8 - 12% and 1.5 - 5% lower than the maximum, respectively. Scenarios without prescribed fire caused diversity to fall 30 - 70%. Trends across the 60 years showed that wildfire depressed diversity and subsequent prescribed fire drove recovery within 15 years. The largest threat to vegetation diversity was the absence of fire. 5. Synthesis and applications. Combining GSO and simulation modelling is a powerful method for defining a conservation-based fire management goal and identifying the prescribed fire regime needed to achieve it. This method provides a flexible platform for developing long term fire management strategies that seek to balance human safety and biodiversity conservation.
R script for growth-stage optimisation, sensitivity analysis, and abundance change
R script for growth-stage optimisation, sensitivity analysis, and abundance change
Growth_stage_optimisation_sensitivity_abundance_change.Rmd
Above-ground species diversity in the juvenile growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. At each site, we counted all above-ground shrub, sub-shrub, and herbaceous species in six 3 × 3 m quadrats, two each at ridge, mid-slope (midway between ridge and gully) and lower-slope/gully locations.
above_juvenile.txt
Above-ground species diversity in the young growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. At each site, we counted all above-ground shrub, sub-shrub, and herbaceous species in six 3 × 3 m quadrats, two each at ridge, mid-slope (midway between ridge and gully) and lower-slope/gully locations.
above_young.txt
Above-ground species diversity in the mature growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. At each site, we counted all above-ground shrub, sub-shrub, and herbaceous species in six 3 × 3 m quadrats, two each at ridge, mid-slope (midway between ridge and gully) and lower-slope/gully locations.
above_mature.txt
Above-ground species diversity in the old growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. At each site, we counted all above-ground shrub, sub-shrub, and herbaceous species in six 3 × 3 m quadrats, two each at ridge, mid-slope (midway between ridge and gully) and lower-slope/gully locations.
above_old.txt
Soil-seedbank species diversity in the juvenile growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. The soil seedbank was sampled by extracting soil cores (6 cm diameter, 5 cm depth) and treating, germinating, and identifying the seeds within.
below_juvenile.txt
Soil-seedbank species diversity in the young growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. The soil seedbank was sampled by extracting soil cores (6 cm diameter, 5 cm depth) and treating, germinating, and identifying the seeds within.
below_young.txt
Soil-seedbank species diversity in the mature growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. The soil seedbank was sampled by extracting soil cores (6 cm diameter, 5 cm depth) and treating, germinating, and identifying the seeds within.
below_mature.txt
Soil-seedbank species diversity in the old growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. The soil seedbank was sampled by extracting soil cores (6 cm diameter, 5 cm depth) and treating, germinating, and identifying the seeds within.
below_old.txt
Above-ground and soil-seedbank species diversity in the juvenile growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. At each site, we counted all above-ground shrub, sub-shrub, and herbaceous species in six 3 × 3 m quadrats, two each at ridge, mid-slope (midway between ridge and gully) and lower-slope/gully locations. The soil seedbank was sampled by extracting soil cores (6 cm diameter, 5 cm depth) and treating, germinating, and identifying the seeds within.
a_combined_juv_ab.csv
Above-ground and soil-seedbank species diversity in the young growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. At each site, we counted all above-ground shrub, sub-shrub, and herbaceous species in six 3 × 3 m quadrats, two each at ridge, mid-slope (midway between ridge and gully) and lower-slope/gully locations. The soil seedbank was sampled by extracting soil cores (6 cm diameter, 5 cm depth) and treating, germinating, and identifying the seeds within.
b_combined_young_ab.csv
Above-ground and soil-seedbank species diversity in the mature growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. At each site, we counted all above-ground shrub, sub-shrub, and herbaceous species in six 3 × 3 m quadrats, two each at ridge, mid-slope (midway between ridge and gully) and lower-slope/gully locations. The soil seedbank was sampled by extracting soil cores (6 cm diameter, 5 cm depth) and treating, germinating, and identifying the seeds within.
c_combined_mat_ab.csv
Above-ground and soil-seedbank species diversity in the old growth-stage
We used fire-history maps to stratify the landscape into four growth stages: 0-3 years since fire (juvenile); 4–10 years (young); 11–34 years (mature); and >34 years (old). We established 71 sites across the range of growth stages within each region. At each site, we counted all above-ground shrub, sub-shrub, and herbaceous species in six 3 × 3 m quadrats, two each at ridge, mid-slope (midway between ridge and gully) and lower-slope/gully locations. The soil seedbank was sampled by extracting soil cores (6 cm diameter, 5 cm depth) and treating, germinating, and identifying the seeds within.
d_combined_old_ab.csv
