Impact of changes in agricultural land use on the Corncrake Crex crex population in Latvia
2005
Keiss, O.(University of Latvia, Riga (Latvia). Faculty of Biology. Dept. of Zoology and Animal Ecology; University of Latvia, Salaspils (Latvia). Inst. of Biology. Lab. of Ornithology)E-mail:[email protected]
Data on Corncrake numbers and agricultural land use were collected in 68 freely chosen sample plots (0.67 - 44.38 square km; mean = 8.42; SD = 7.458) in Latvia 1984 - 2004. The annual TRIM index of Corncrake numbers in Latvia increased significantly during the study period (p is less than 0.003). The total area of all abandoned agricultural lands have increased significantly (p is less than) at the expense of cultivated pasture (p is less than 0.015) in the survey plots. The area of intertilled crops also decreased (p is less than 0.07). The area of both cultivated and uncultivated meadows increased significantly during the period of 1989-1998 (p is less than 0.005), and decreased in 1999-2004 (p is less than 0.025). The habitat-specific annual TRIM index of Corncrake numbers was positively correlated with the TRIM index of area of uncultivated meadows (p is less than 0.001), all meadows combined (p is less than 0.001), uncultivated pastures (p is less than 0.05) and abandoned agricultural lands (p is less than 0.0025), but negatively with the TRIM index of area of intertilled crops (p is less than 0.05). The total Corncrake TRIM index was positively correlated (p is less than 0.002) with the total amount of precipitation during the Corncrake breeding season (May - July).
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