Has the accuracy of the biodiversity index predicted by the Cool Farm Tool been tested in the field?
No, the tool has not been validated against empirical biodiversity data. This will be an important step for us, and one we are very keen to get funding for. However, the differences in species richness and abundance of indicator groups according to farm management are likely to be smaller than the differences between farms according to ecological context at a range of scales (including regional species pool, local habitat availability and diversity, very local habitat quality). This means that
- Comparison across many farms with different CFT Biodiversity scores might only be valid if data on surrounding landscape and habitats, and if sufficient farms were available to take this variation into account statistically.
- The tool could be validated by measuring differences over time at the same farms. Due to the variability between years in biodiversity, especially for small-bodied, mobile taxa like insects and small birds, this longitudinal study will need to take place over multiple years.
- For the scores to be correlated with actual biodiversity, you would almost certainly need to weight the large natural habitat component more heavily, or expect a stronger correlation in that component. This is a small component of the tool, but probably has the biggest impact on farm biodiversity.