 Some Hydnellum species have been shown to be in decline in Europe , including the Czech Republic , the Netherlands , Norway , and Scotland . In the United Kingdom , several are listed in the biodiversity action plan for stiped hydnoid fungi : H. aurantiacum is classified as critically endangered ; H. caeruleum , H. ferrugineum are listed as endangered , while H. concrescens , H. spongiosipes , H. peckii , and H. scrobiculatum are considered vulnerable . H. ferrugineum and H. peckii are sensitive to the increased nitrogen deposition resulting from clear @-@ cutting , a forestry practice used in some areas of Europe . 
