Boris Schröder 7 Connectivity compensates for low habitat quality and small 8 patch size in the butterfly

9 10 Received: 20 March 2006 / Accepted: 21 February 2007 11 The Ecological Society of Japan 2007 23456 17 18 Abstract Habitat size, habitat isolation and habitat 19 quality are regarded as the main determinants of but20 terfly occurrence in fragmented landscapes. To analyze 21 the relationship between the occurrence of the butterfly 22 Cupido minimus and these factors, patch occupancy of 23 the immature stages in patches of its host plant Anthyllis 24 vulneraria was studied in the nature reserve Hohe Wann 25 in Bavaria (Germany). In 2001 and 2002, 82 A. vulner26 aria patches were surveyed for the presence of C. mini27 mus larvae. The occurrence was largely affected by the 28 size of the food plant patches. In a habitat model that 29 uses multiple logistic regression, the type of management 30 and habitat connectivity are further determinants of 31 species distribution. Internal and temporal validation 32 demonstrate the stability and robustness of the devel33 oped habitat models. Additionally, it was proved that 34 the colonization rate of C. minimus was significantly 35 influenced by the distance to the next occupied Anthyllis 36 patch. Concerning long-term survival of (meta-) popu37 lations in fragmented landscapes, the results show that 38 lower habitat quality may be compensated by higher 39 connectivity between host plant patches.