Predation on simulated duck nests in relation to nest density and landscape structure

Abstract

Context Density-dependent predation has been recently discussed as a contributing cause of duck nest failure. Aims We tested whether nest density increases the nest predation rate (density-dependent predation) in patches of littoral vegetation surrounding fishponds in two contrasting landscape types, the first dominated by forest and the other dominated by agricultural fields. Methods In total, 576 simulated ground nests were deployed in 48 littoral patches in South Bohemia, Czech Republic, in two replicates (June and July), for two consecutive years (2005 and 2006). Nests were deployed either solitarily (low-density plots) or in groups of five nests (high-density plots). Key results Despite differences in local predator communities, we found no evidence of different survival rates of solitary nests and nests placed in high-density patches in either habitat. Mammalian predators were the most common nest predators, followed by birds. The composition of nest predator community depended on landscape type, with mammals predominating in forest landscape and birds in agricultural areas. Our data thus do not support the theory of density-dependent predation of duck nests in littoral patches, regardless of predominant nest predator type. Conclusions Based on our results, we conclude that nest predator responses to different habitats are complex, taxon specific, and context dependent. Implications Conservation efforts for waterfowl may need to be customised according to the nest-predator species primarily responsible for local nest mortality and the nature of the landscape mosaic.

Temporal variation in nest predation risk along habitat edges between grassland and secondary forest in Central Europe

“…This species may also pose a potential challenge for the conservation of native biota, especially due to its omnivorous feeding and rooting activity, which has been surprisingly little studied (but see for example Hone 2002). To our knowledge, ours is the first study providing evidence that high wild boar abundances may result in increased predation risk for clutches of ground-nesting birds and possibly for other types of less mobile prey (but see also Padyšáková et al 2010). Nevertheless, determining the effect of wild boar on local biodiversity requires further empirical studies.…”

The fine-scale utilization of forest edges by mammalian mesopredators related to patch size and conservation issues in Central European farmland

“…Similarly we excluded domestic dogs from our analysis because their presence is mostly dependent on human activities (see Lenth et al 2008). All these documented carnivore species are important predators of ground-nesting birds (Mazgajski and Rejt 2005;Storch et al 2005;Albrecht et al 2006;Padyšáková et al 2009;Weidinger 2009;Padyšáková et al 2010). …”

Density-dependent nest predation in waterfowl: the relative importance of nest density versus nest dispersion

“…Some artiWcial nest studies report strong patterns of densitydependent nest predation (e.g., Gunnarsson and Elmberg 2008), while others report weak (e.g., Clark and Wobeser 1997) or no (e.g., Padysakova et al 2010) density-dependent eVects on nest predation rates. The lack of consensus on the role of density-dependent predation may have arisen, in part, because of considerable variation in how researchers have studied nest predation.…”