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In recent decades, Skylark ( Alauda arvensis) populations in Europe have declined sharply due to agricultural intensification. Insufficient reproduction rates are one reason. Increased winter mortality may also be important, but studies outside the breeding season are scarce and mostly limited to the UK. We studied habitat selection of wintering Skylarks in an agricultural area in the Netherlands. We monitored Skylarks between November 2008 and March 2009 on 10 survey plots including 77 different arable fields and permanent grasslands and covering in total 480 ha. We simultaneously measured food availability, vegetation structure and field boundary characteristics. We also analysed 158 faecal pellets collected on potato and cereal stubble fields to relate Skylark diet to seasonal changes in food availability and foraging habitat. We show that cereal stubble fields larger than 4.3 ha, surrounded by no or low boundary vegetation and a density of dietary seeds of more than 860 seeds m, were most suitable for wintering Skylarks. Skylark group densities were low on permanent grasslands and on maize stubble fields. Densities of dietary seeds were highest in soils of potato stubble fields followed by cereal stubble fields, grasslands and maize stubble fields. Skylarks showed a strong preference for cereal grains, but their proportion in the diet fell sharply at the end of November, indicating that cereal grains were depleted and birds had to switch to less profitable food sources, such as weed seeds and leaves. We conclude that Skylarks wintering in agricultural landscapes possibly suffer from a lack of energy-rich food sources and only a few fields provide sufficient food. Conservation measures should strive to improve the wintering situation by creating food-rich habitats such as over-winter stubble with a rich layer of weeds on large fields and localised in open areas. [ABSTRACT FROM AUTHOR]

Abstract: This study examined the effects of agricultural intensity, various farming practices, landscape composition and vegetation cover on the abundance and species richness of wintering farmland birds, assessed simultaneously across seven European regions. The abundance and species richness of wintering farmland birds were negatively affected by agricultural intensity. The effects of yield and farm type were interlinked. Of the 10 farming practices assessed, mechanical weeding and the amount of organic fertilizer applied negatively affected farmland birds, presumably due to reduced food availability on arable fields. Positive effects of organic farming on farmland birds proved to be limited to simplified landscapes. More farmland birds were observed in areas with more stubble, pasture and green manure crops. Species richness was higher in areas with more pasture. The results of this study show that farm management, vegetation cover and landscape composition all influence wintering farmland birds. Heterogeneous landscapes comprising arable crops as well as grasslands support most species of farmland birds in winter. The effectiveness of organic farming and agri-environment schemes depends on landscape composition. Therefore, different agri-environment schemes should be designed for different landscape types. [ABSTRACT FROM AUTHOR]

Abstract: European farmland bird populations have decreased dramatically in recent decades and agricultural intensification has been identified as the main cause contributing to these declines. Identifying which specific intensification pressures are driving those population trends seems vital for bird conservation in European farmland. We investigated the response of ground-nesting farmland birds to the multivariate process of agricultural intensification in six European countries covering a bio-geographical and intensification gradient. Supported by PCA analysis, two groups of factors, related to field management and landscape modification, were considered, seeking to discriminate the relative importance of the effects of these main intensification components. Variance partition analysis showed that landscape factors accounted for most of the variation of ground-nesting farmland bird individual and breeding pair densities, as well as Skylark (i.e. our single model species) individual densities. In the case of Skylark breeders, field factors were found to be more important to explain their density. Our results suggest that in general farmland bird densities as well as Skylark densities are higher in simple landscapes dominated by agriculture, but with smaller fields and more different crops on the farms. In addition, high yields were negatively related to bird densities. We conclude that while management actions aimed at farmland bird conservation taken at landscape level may exert a strong positive effect on overall bird densities, those taken at field level are also relevant, particularly for breeders and, therefore, may potentially influence the persistence of these species’ populations. [Copyright &y& Elsevier]

Organic farming in Europe has been shown to enhance biodiversity locally, but potential interactions with the surrounding landscape and the potential effects on ecosystem services are less well known. In cereal fields on 153 farms in five European regions, we examined how the species richness and abundance of wild plants, ground beetles and breeding birds, and the biological control potential of the area, were affected by organic and conventional farming, and how these effects were modified by landscape complexity (percentage of arable crops within 1000 m of the study plots). Information on biodiversity was gathered from vegetation plots, pitfall traps and by bird territory mapping. The biological control potential was measured as the percentage of glued, live aphids removed from plastic labels exposed in cereal fields for 24 h. Predation on aphids was highest in organic fields in complex landscapes, and declined with increasing landscape homogeneity. The biological control potential in conventional fields was not affected by landscape complexity, and in homogenous landscapes it was higher in conventional fields than in organic fields, as indicated by an interaction between farming practice and landscape complexity. A simplification of the landscape, from 20% to 100% arable land, reduced plant species richness by about 16% and cover by 14% in organic fields, and 33% and 5·5% in conventional fields. For birds, landscape simplification reduced species richness and abundance by 34% and 32% in organic fields and by 45·5% and 39% in conventional fields. Ground beetles were more abundant in simple landscapes, but were unaffected by farming practice. Synthesis and applications. This Europe-wide study shows that organic farming enhanced the biodiversity of plants and birds in all landscapes, but only improved the potential for biological control in heterogeneous landscapes. These mixed results stress the importance of taking both local management and regional landscape complexity into consideration when developing future agri-environment schemes, and suggest that local-regional interactions may affect other ecosystem services and functions. This study also shows that it is not enough to design and monitor agri-environment schemes on the basis of biodiversity, but that ecosystem services should be considered too. [ABSTRACT FROM AUTHOR]