Selected SSSI sites in HLS agreement were assessed for vegetation condition, and soil properties. Associations were found between soil variables and condition status of the National Vegetation Classification (NVC) communities. Findings include that pH, availability of phosphorus and organic matter content were highly indicative factors with unfavourable condition being related to high available phosphorus levels.
There appeared to be a strong association between low organic matter content and under-management, with mixed grazed and mown sites having the highest levels of organic matter. This may have important implications for carbon storage in semi-natural habitats.
The results also raise the possibility that on some SSSIs, phosphorus status may have increased since they were originally designated, potentially causing a decline in their condition and a risk to their continued priority habitat status.