In reply to JDal: sorry, I wasn't going to bite, but as there has been some other discussions of wider moorland management, I'll sling in my own 2 bob
My hackles raised at the 1000 years statement. There isn't really any evidence of regular burning in the pollen stratigraphy since before around 1500, and certainly no evidence of frequent burns for grouse moor from much before 1800.
The issue of soils is certainly of interest, the peat has degraded dramatically on some parts of the peat uplands, partly due to climate change (the old fashioned sort) partly due to management, mostly due to fires, intentional or otherwise. Industrial pollution has also been an important factor. The soil chemistry now is different than it was when grouse manageent started, and the heavy metal levels in most of the pennine moors are quite alarming.
Frequent burning for grouse favours a relative few species - the biodiversity of moorlands is quite low, although, granted several of the species are of conservation importance - many of these species were of course persecuted till very recently by game keepers as they either predated or competed for food with, the grouse.
Burning, even light rotational burning, can have severe effects on things like lichen - not sexy, but important non the less and of course terrestrial invertebrates get fried if they can't outrun the fire front. lower plants and inverts are the base of our notional pyramid of dependency, so may have unforseen effects on higher species.
What else? Burning is plat du jour amongst the carbon studying community as it contributes both directly and indirectly (through exposing peat for oxidisation) to release of CO2 and therefore man induced climate change.
Perhaps the most pertinent issue is that of colour in drinking water supplies (humic and fulvic acids released from peat make the water go brown, especially on burned moors)- certainly this is where a lot of upland research money is being pointed, as this has potential health, as well as aesthetic implications.
sorry for the minor hijack, but as we were discussing peat and burning, I thought it might be useful contextual stuff.