Promotor: G.R. de Snoo
|Links||Thesis in Leiden Repository|
As a result of agricultural intensification, farmland bird populations have been declining dramatically over the past decades. Organic farming is often mentioned to be a possible solution to stop these declines. In order to see whether farmland birds really benefit from organic farming a study was carried out comparing breeding bird densities, breeding success and bird food abundance between organic and conventional arable farms in Flevoland, the Netherlands. skylark (Alauda arvensis) and lapwing were both found in higher densities on organic farms, but for other species no differences were found. Differences in skylark densities were caused by relative large areas of spring cereals grown on organic farms. Differences in lapwing densities were probably caused by higher food abundance and greater availability of suitable breeding habitat on organic farms. In contrast with the higher densities of breeding pairs, indications were found that breeding success of lapwings is lower on organically managed farms. This is a result of mainly mechanical weeding and other agricultural operations. Also for skylarks breeding on organic farms agricultural operations are the most important cause of nest failure. Greater food availability on organic farms might compensate for this high nest loss through higher chick survival rates.