PREDICTING SPACE USE RESPONSES TO HABITAT FRAGMENTATION - CAN VOLES MICROTUS-OECONOMUS SERVE AS AN EXPERIMENTAL-MODEL SYSTEM (EMS) FOR CAPERCAILLIE GROUSE TETRAO-UROGALLUS IN BOREAL FOREST

We found similarities in space use responses by individual root voles Microtus oeconomus and capercaillie grouse Tetrao urogallus to habitat fragmentation. Male capercaillies and some male voles responded to a fine-grained fragmentation pattern by expanding their home ranges to include more than one habitat fragment. Breeding female voles belonging to a northern, aggressive strain spread out over single habitat fragments (fission response) when the habitat was moderately coarse-grained The same response was shown by lekking capercaillie males in the spring; as their spring lek habitat gradually became more coarse-grained due to logging, coalitions of neighbouring males dissolved, resulting in solitary displaying individuals. Breeding female voles belonging to a southern, docile strain and capercaillie males (in the non-breeding season) responded to a coarse-grained habitat fragmentation by congregating with highly overlapping home ranges on remaining habitat patches. Our results suggest that experimentally tractable species (e.g. voles) may be used as Experimental Model Systems (EMS) to predict responses by other wildlife species (such as capercaillie grouse) which are less amenable to experimentation.