Carrying Capacities

I think what would be interesting Steve is to consider what actually affects carrying capacity. Generally food supply is the one I hear quoted. I think only in exceptional circumstances does this represent a real limiting factor.. suitable 3D habitat structure and basking opportunity seem much higher on the list from my field observations. Clearly egg laying sites make a huge difference to Sand Lizard populations and soil types and structure have their influences on many of the widespread species, predation is another issue that influences observed numbers. Perhaps consider going for some sort of index for these essential features in the study else the 'average' carrying capacity is a little meaningless.

Regarding your figures none seem unreasonable for optimal type habitat, I'm not convinced it represents 'average' habitat but of course the terms are entirely subjective. One also has to consider that mobility of the species, intercepting 20 grass snakes in a hectare might be hard work, yet that hectare could easily be part of a larger picture for the species and actually be supporting far more animals that are not actually resident at any given time.

GemmaJF wrote: Regarding your figures none seem unreasonable for optimal type habitat, I'm not convinced it represents 'average' habitat but of course the terms are entirely subjective.

Heh, well I can actually define 'average' habitat objectively...for Surrey, at 1km grid fidelity.

here's an example for Ca

I know, that on average, for each occupied grid, I have two occupied hectares.

Your suggestion for modelling the CC for a hectare is, I think, sound. My trouble is, for trying to assess FCS at county-level, I'm never going to be able to gather the required data for widespread species.

I agree that the CC figures I've quoted seem on the high-side for average habitat. What I'd really like to avoid is using subjective values that 'feel' right. I'd rather go with endorsed figures derived from sound research...I wonder if there are any?