Suitability of poplar plantations for a cavity-nesting specialist, the Lesser Spotted Woodpecker Dendrocopos minor, in the Mediterranean mosaic landscape

Abstract

Monocultures of even-aged trees in short rotation are a forest system of low ecological complexity that has been described as unsuitable for the establishment of stable populations of forest birds. However, key habitat quality cues could make them attractive to forest specialists. This paper assesses the suitability of poplar plantations in the northeast of the Iberian Peninsula for a forest specialist, the Lesser Spotted Woodpecker Dendrocopos minor. Poplar stands occupy a small area of an agroforestry mosaic landscape where semi-natural Mediterranean woodland is predominant. Population size, nesting success, home ranges and habitat selection were studied by radio-tracking and monitoring during the breeding season and the winter. Poplar plantations were preferentially selected for breeding and foraging in the spring and the winter. Home ranges in the breeding season and the winter (32.4 and 438.5 ha, respectively) were similar to those observed in semi-natural woodlands that have been studied in Europe. However, population density (0.25 territories/100 ha) was lower than that described in most European semi-natural woodlands. Nesting success was low (0.54), due to strong competition with other cavity nesters, predation of nests by the Greater Spotted Woodpecker, and loss of one of the adults. Fifty per cent of the foraging activity during the breeding season took place in an area of 180 metres around the nest. The amount of standing dead wood in poplar stands was much higher than in the surrounding habitats and source areas. The moderate breeding success and the high rate of adult predation may suggest that poplar plantations act as an ecological trap, in which standing dead wood may be a habitat quality cue that attracts birds to this non-ideal habitat. Poplar plantations become even less suitable when most of the available habitat is felled at the same time. Suitable planning of poplar plantation rotations and recovery of riparian forest is the best way to ensure the survival of Lesser Spotted Woodpecker populations in the long term.