Abstract
:Habitat fragmentation may have a negative impact on bird populations by increasing nest predation along disruptive habitat edges. We monitored the fate of artificial ground nests (n = 598) in a highly fragmented, recently deforested landscape in the Krušné hory mountains (Czech Republic) that hosts a declining population of the black grouse (Tetrao tetrix). We evaluated the generality of the “edge effect on nest predation” hypothesis in three dominant habitats available for breeding grouse i.e., mature forests (> 50 y old), young forests (< 30 y old), and open landscapes. The resulting spatial pattern of nest predation was further compared with the grouse occurrence in order to test the ecological trap hypothesis. Predation on artificial nests was low (17.7%) and was similar among the three habitat types and for edge and interior areas, suggesting that edge effects do not contribute to elevated predation on grouse nests in Krušné hory mountains. The results do not support the ecological trap hypothesis, because predation pressure on artificial nests was lower in areas occupied by the grouse. Nest concealment was closely associated with nest fates, despite mammalian predators (foxes) being responsible for the majority of nest predation events. Ground nests placed under a shelter of branches in young forests were more successful than concealed nests in other habitats. Hence, this microhabitat may potentially act as the most productive grouse-nesting habitat in the area. Successional changes and maturation of intensively managed forests may result in higher predation rates on natural grouse nests and may contribute to overall population decline of this species.
Published Version
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