Very interesting study. Been here awhile and yes the brush line is moving up slowly, but not nearly as fast as the glaciers are melting. Animals all over Alaska do not have the time to adapt as they have over the eons. Global warming is happening faster than thought and the evidence is overwhelming visually and scientifically. In 50 years the Western Chugach sheep population will be least of our concerns. Our scientific minds need to focus on how humans are going to adapt just to feed ourselves along with technology to greatly reduce our carbon use. Faster is better.