On the surrogate value of red-listed butterflies for butterflies and grasshoppers: a case study in Grammos site of Natura 2000, Greece

We tested the surrogate value of butterflies, red-listed butterflies and grasshoppers for each other in terms of diversity patterns congruence and complementarity at a site in the NATURA 2000 network. Grammos Mountain is proposed as a new Prime Butterfly Area for Greece: it supports a total of 56 grasshopper species and 112 butterfly species, 24 of which are of European conservation concern (SPEC) and two of Prime Butterflies Area Project. We found a strong congruence in the species richness patterns of SPEC butterflies, butterflies and grasshoppers, because three common ecological factors influenced them: number of flower heads, altitude, and cover of low trees or bushes (Redundancy Analysis, CANOCO). Each complementarity network maintained quite well the species richness of the other two target groups (<18% average species loss). SPEC butterflies were the best surrogate group overall and therefore we propose that they should be monitored on a permanent basis.