Brae Pasture is within the Ingleborough National Nature Reserve, in an area of calcareous grassland with smaller patches of degraded acid grassland and rushes. Situated near Selside it overlooks the Ribble Valley towards Pen y Ghent. The transect route covers the majority of Northern Brown Argus habitat patches in this particular area. The diversity of habitats support a wide range of plants, invertebrates and birds including notable species such as blue moor grass, bird's-eye primrose, alpine bistort and frog orchid.

S1 has seen the odd Brimstone and is the only section where Large Skipper is seen . S2 and S5 are favourites with Common Blue , and Meadow Browns. Ringlets prefer S2-3 Dark Green Fritillaries prefer S4 and Small Heath S5-7 Northern Brown Argus in S3 + S6