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Effects of variations in micro-mammal abundance on artificial nest predation in conifer plantations and adjoining deciduous forests

2002; Elsevier BV; Volume: 157; Issue: 1-3 Linguagem: Inglês

10.1016/s0378-1127(00)00650-2

1872-7042

Vincent Carignan, Marc‐André Villard,

Wildlife Ecology and Conservation

Although conifers are extensively planted throughout the world, relatively few studies have investigated the effects these plantations might have on communities of nest predators and avian reproductive success. To address these issues, we placed artificial nests containing plasticine eggs along transects perpendicular to the edge between mature hardwood forests and adjacent spruce plantations in a managed forest landscape of northwestern New Brunswick, Canada. We used logistic regression models to assess the relative influence of habitat type, vegetation characteristics, distance from the nearest forest/plantation edge, and year on the risk of nest predation. In 1998, nest predation was significantly higher (P<0.0001) in plantations (45.8%) than in forests (19.4%), and the probability of nest predation was negatively related to the density of stems 0.5–1 m high, and positively related to the density of stems 6–8 m high. In 1999, nest predation was not related to habitat type but was positively related to the density of stems 2–4 m high and negatively related to percent cover of bare ground. The distance to the nearest forest/plantation edge did not significantly contribute to either model. In 1998, black bear (Ursus americanus) was the most frequent nest predator (44% of depredated nests), whereas micro-mammals were in 1999 (49% of depredated nests). The high degree of temporal variability we recorded in the relative influence of various nest predators was apparently related to changes in their abundance between years, which in turn may have influenced which variables were significant predictors of the probability of nest predation each year. Conifer plantations did not appear to represent ecological traps for breeding birds, at least not consistently over time.