The 108 acres of dark gray on the map represents Rocky Ridges. The 140 acres of red is the related habitat of Cliff and Talus Slopes. These provide crucial habitat for several rare wildlife species including bobcat, Eastern towhee, smooth green snake, northern black racer and golden eagle. Cliffs have sparse vegetation that is typically restricted to cracks and crevices where soil accumulates. Depending on the type of rock that make up the cliff, different types of vegetation will grow there such as sheep laurel on acidic cliffs and bulblet bladder fern on calcareous cliffs. The biggest threat to these areas is overuse by humans. Some conservation strategies for rocky ridges, cliffs, and talus slopes are educating recreational users, limiting trails through high risk areas, and monitoring indicator species for climate change.
Foss Mountain has both Rocky Ridges and Cliff and Talus Slopes.
The information on Cliffs and Ridges comes from the Wildlife Action Plan of the New Hampshire Fish and Game Department: https://www.wildlife.nh.gov/wildlife-and-habitat/nh-wildlife-action-plan
Related topics: geology – areas of calcareous rock are indicative of rare plants