The Today program this morning was looking at "Heritage at Risk" this is English Heritage's program highlighting those heritage buildings most at risk. http://www.english-heritage.org.uk/caring/heritage-at-risk/
It is a good methodology and we would like to see a parallel system highlighting living heritage at risk. Another model is the red data list for species or the "watch list" of the rare breed survival trust https://www.rbst.org.uk/rare-breeds-watchlist. The first step toward any of these lists is a survey of what you have got in the first place, we have not even got that far yet. As Joni Mitchel sang "don't it always seem to go you don't know what you got til it's gone"