The "edge effect on nest predation" hypothesis after twenty years

A majority of empirical tests have failed to support the hypothesis that avian nest predation increases near habitat edges. Of 54 study sites, 13 exhibited an edge effect in any test conducted, 31 did not exhibit one, and 10 exhibited an edge effect in at least one treatment but not in at least one other. Edge type has not generally been supported as an important factor in determining the existence of an edge effect.. An edge effect has been exhibited slightly more often in landscapes of high fragmentation (< 50% prey habitat) than low (> 75% prey habitat), especially in forest. The few studies containing reliable predator identification have explained their results with species-specific predator behavior and its relation to habitat and landscape features. This may be a more fruitful approach to understanding nest predation dynamics than a focus on habitat edges per se. (C) 2001 Elsevier Science Ltd. All rights reserved.