Ardea
Official journal of the Netherlands Ornithologists' Union

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Kossenko S. & Kaygorodova E. (2007) Reproduction of the Middle Spotted Woodpecker Dendrocopos medius in the Nerussa-Desna woodland, SW Russia, with particular reference to habitat fragmentation, weather conditions and food supply. ARDEA 95 (2): 177-189
The Nerussa-Desna woodland (south-western Russia) is one of the core areas for the Middle Spotted Woodpecker Dendrocopos medius, a habitat specialist restricted mainly to mature oak forests. Recent studies have shown a lower breeding density of the species in fragmented compared with continuous habitat. To evaluate reproduction as a possible mechanism underlying the fragmentation effects, we studied reproductive performance of the species in both continuous habitat and fragmented habitat in the forested landscapes of the Nerussa-Desna woodland. During 19972001, annual variation of reproductive indices in both continuous and fragmented habitat was insignificant. None of the indices was significantly lower in fragmented habitat though nestling losses were significantly higher in fragments. Timing of breeding in 2000 was later in fragmented than continuous habitat, probably due to differential landscape phenology. In fragments, fledging success in a year was inversely related to the mean amount of rain. On the basis of individual pairs, fledgling production also correlated significantly and negatively with the amount of rain during the nestling period in food-poor fragments only. In 19992001, abundance of Lepidoptera larvae, main food for the Middle Spotted Woodpecker during nestling phase, varied significantly in continuous habitat, whereas in fragmented habitat the patterns of variation differed between fragments. No significant correlation was found between larval density and reproductive performance of individual pairs in either habitat. Large oak density, a habitat feature related to potential food abundance, was higher in fragments than in continuous habitat but was not related to the reproductive performance. The lower larval density within some territories in fragments as opposed to continuous habitat is likely to explain higher nestling mortality in fragmented compared to continuous habitat. Generally, we found little evidence for lowered reproductive performance in relation to fragmentation. Therefore, this seems unlikely to be responsible for the fragmentation-sensitive patterns of density.


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