Abstract

The strength of 'edge effects' on Marbled Murrelet (Brachyramphus marmoratus) nesting success affects the relative murrelet productivity value of sites of different size and spatial configuration. Knowledge of their magnitude therefore informs policy on recognition of the value of existing and proposed Wildlife Habitat Areas and other areas where suitable habitat is maintained. Extremely limited observational data suggest that the magnitude of edge effects may vary as a function of landscape variables; experimental studies in Washington State provide stronger evidence of such variation, with human-occupied edges being the most deleterious. We conducted experiments on north-eastern Vancouver Island to determine the potential relative vulnerability to predation and microclimate differences between simulated nest sites located along different kinds of edge versus interior habitat, adding to last year’s studies on the Sunshine Coast. Sites were located at natural, regenerating, and recently formed industrial edges in the Nimpkish Valley. Non-trivial negative edge effects are present in the specific sites and landscape studied, but the patterns differ between regions. Our techniques work and have sufficient power to detect differences in potential edge effects among landscapes.
David B. Lank and Josh M. Malt.

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