The original publication came out in 1998. It was initially targeted to the Great Lakes areas of concern. It laid out specific targets for things such as forest cover, the percentage of stream length that's naturally vegetated, the percentage of wetland cover—those types of targets. The idea was that if you achieved those targets for coverage of different habitat types, you would maintain the full suite of biodiversity in those areas.
The guidelines were updated in the early 2000s. The most recent version came out just a few weeks ago, in fact; they've been updated through three editions.
As we use them, when we're doing watershed planning we look at those guidelines to think about what kinds of targets we should be looking at when doing restoration work. These guidelines have been really well received.