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Movements and mortality of common goldeneye Bucephala clangula broods in a patchy environment

Authors

  • Hannu Pöysä,

  • Antti Paasivaara


H. Pöysä, Finnish Game and Fisheries Research Inst., Joensuu Game and Fisheries Research, Yliopistokatu 6, FIN-80100 Joensuu, Finland (hannu.poysa@rktl.fi). – A. Paasivaara, Finnish Game and Fisheries Research Inst., Oulu Game and Fisheries Research, Tutkijantie 2 A, FIN-90570 Oulu, Finland and Dept of Biology, Univ. of Oulu, P.O. Box 3000, FIN-90014 University of Oulu, Finland.

Abstract

Effects of habitat configuration on movements, space use, and mortality of individuals are crucial for our understanding of the dynamics and persistence of populations in patchy environments. We studied these aspects in a naturally patchy environment using radio-marked common goldeneye (Bucephala clangula) females with their broods. The landscape consisted of suitable patches (lakes) and definitely inhospitable matrix (all terrestrial habitat surrounding the lakes), many of the patches being connected with corridors of varying usability (semipermanent and permanent ditches). We focused on habitat-related factors potentially affecting the decision of common goldeneye females and broods to leave the hatching patch, the rate of movement within the landscape, and the first-week mortality of ducklings when moving within the landscape. The probability to leave the hatching patch was high if the number of neighbouring patches was high, whereas mean distance to neighbouring patches and the presence and usability of corridors did not affect the probability to leave the hatching patch. Different measures of distance moved (i.e. within patches, through corridors, through matrix) were not strongly associated with any of the variables measuring habitat configuration. Corridors were used when available, but the broods also frequently moved through the matrix. There was no significant difference in the daily mortality rate of ducklings between broods that stayed in the hatching patch and broods that left the hatching patch. Among the broods that left the hatching patch, high daily mortality rate was associated with the lack and low usability of corridors. Daily mortality rate of ducklings was not associated with the distance moved through the matrix, nor with the other measures of distance moved or the variables measuring habitat configuration. Our findings suggest that species living in naturally patchy environments may have evolved remarkable skills to successfully cross an inhospitable matrix when changing patches.

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