Breeding bird communities in pine plantations of the Spanish plateaux: biogeography, landscape and vegetation effects

Abstract

Summary Afforestation with pines (Pinus pinaster and, to a lesser extent, P. pinea and P. halepensis) seems to be the most probable land‐use change over large areas of dry cereal croplands in central Spain in the next 10–20 years. This will be encouraged by changes in the subsidy policies of the Common Agricultural Policy that aim to decrease food production and restore the environmental diversity previously lost through agricultural intensification. This study addresses the factors influencing the richness and composition of breeding bird communities in these pine plantations and evaluates the potential environmental benefits of the afforestation programmes. The complement of bird species breeding in 88 plantations ranging in size from 0.1 to 6775 ha was determined. Plantations were characterized according to size, distance to the nearest large plantation, vegetation structure and geographical location (northern moist vs. southern xeric Iberian plateaux). Plantation size alone accounted for 67–75% of the variation in species richness, and was also the maintrait explaining the patterns of presence/absence of most individual bird species. Plantations smaller than 25 ha only maintained 50% of the regional pool of forest birds during breeding, whereas this proportion increased to 69–86% for plantations of 25–100 ha. Geographic location, degree of isolation and vegetation structure were also important. Bird species richness decreased with distance to a large plantation, and increased with prevalence of undergrowth shrubs and with plant species richness. Both species richness and the incidence of individual species in plantations were affected by geographical location. They were greater in plantations of the northern plateau, reflecting a trend of increasing densities of most forest bird species in Spain in more northerly locations. The results of this study suggest that re‐afforestation of former arable land in the Spanish plateaux is unlikely to increase species richness in forest bird communities. Given the regional scarcity of many forest birds and the small scale of new plantations, re‐afforestation schemes are unlikely to promote rich forest bird communities. Since plantations are unsuitable habitats for the bird species breeding in Spanish dry cereal croplands, and such birds have a high conservation value because of their small and declining populations the overall environmental benefits of large‐scale afforestation programmes will not include increased diversity of birds.

Influences of forest type and habitat structure on bird assemblages of oak (Quercus spp.) and pine (Pinus spp.) stands in southwestern Turkey

“…Stand size and connectivity to surrounding forest stands are known to be important determinants of forest bird assemblages in both native forests and plantations (e.g. van Dorp and Opdam, 1987;Enoksson et al, 1995;Díaz et al, 1998), implying that smaller isolated patches of forests may have a lower species richness than larger patches of the same habitat. In a Spanish study, Santos et al, (2002) found that native stands of holm oak (Q. ilex) had to be of significantly larger size than similar stands located in central Europe in order to support equal numbers of bird territories and species.…”

Contribution of poplar plantations to bird conservation in riparian landscapes

“…The landscape matrix should include a high percentage of poplar plantations, with a distance between the plantations of less than 400 m, to provide forest bird species with well connected supplementary forest habitats. However, as the effect of large scale forest plantations in agricultural areas may also adversely affect threatened bird communities of open habitats (Diaz et al 1998;Reino et al 2009), we suggest that future poplar plantations might be considered within a global landscape planning perspective taking into account all relevant bird habitats such as grasslands and riparian forests.…”

“…However, if the effect on bird diversity of increasing area of planted forests has already been tested in Mediterranean landscapes (see Diaz et al 1998;Reino et al 2009), it has seldom been tested in landscapes including remnants of riparian forest, poplar plantations and agricultural land.…”

Environmental factors affecting the densities of owls in Polish farmland during 1980–2005

“…Moreover, in many European countries, some parts of open habitats, especially less productive ones, have been afforested within the framework of programs to increase forest cover. This has had an additional negative impact on many farmland birds (Diaz et al 1998;Marchesi & Sergio 2005). The transformations of farmland habitat resulted in the decline of many bird species inhabiting the open landscape in Central and Eastern Europe (Donald et al 2006;Chylarecki & Jawińska 2007;Lawicki et al 2011).…”