BIOTIC FACTORS 



273 



\ ■?.'>.— Xnrdus meadow destroyed by excessive sheep grazing and resulting erosion 

 U^iiii, ill iLe heart of the beech region of the Aigoual, 1,250 m., South Cevennes. 



Fig. 140. — Thorn-bush garigue of Astragalus poterium with scraggly remains of the 

 macchia of Pistacia lentiscus upon Majorca. {Photo by Hoffmann-Grobety.) 



