A1 Vertaisarvioitu alkuperäisartikkeli tieteellisessä lehdessä
When and where to count? Implications of migratory connectivity and nonbreeding distribution to population censuses in a migratory bird population
Tekijät: Piironen Antti, Fox Anthony D, Kampe-Persson Hakon, Skyllberg Ulf, Therkildsen Ole R, Laaksonen Toni
Kustantaja: WILEY
Julkaisuvuosi: 2023
Journal: Population Ecology
Tietokannassa oleva lehden nimi: POPULATION ECOLOGY
Lehden akronyymi: POPUL ECOL
Sivujen määrä: 12
ISSN: 1438-3896
eISSN: 1438-390X
DOI: https://doi.org/10.1002/1438-390X.12143
Verkko-osoite: https://doi.org/10.1002/1438-390X.12143
Rinnakkaistallenteen osoite: https://research.utu.fi/converis/portal/detail/Publication/177228755
Migratory connectivity is a metric of the co-occurrence of migratory animals originating from different breeding sites, and like their spatial dispersion, can vary substantially during the annual cycle. Together, both these properties affect the optimal times and sites of population censusing. We tracked taiga bean geese (Anser fabalis fabalis) during 2014-2021 to study their migratory connectivity and nonbreeding movements and determine optimal periods to assess the size of their main flyway population. We also compared available census data with tracking data, to examine how well two existing censuses covered the population. Daily Mantel's correlation between breeding and nonbreeding sites lay between 0 and 0.5 during most of the nonbreeding season, implying birds from different breeding areas were not strongly separated at other times in the annual cycle. However, the connectivity was higher among birds from the westernmost breeding areas compared to the birds breeding elsewhere. Daily Minimum Convex Polygons showed tracked birds were highly aggregated at census times, confirming their utility. The number of tracked birds absent at count sites during the censuses however exceeded numbers double-counted at several sites, indicating that censuses might have underestimated the true population size. Our results show that connectivity can vary in different times during the nonbreeding period, and should be studied throughout the annual cycle. Our results also confirm previous studies, which have found that estimates using marked individuals usually produce higher population size estimates than total counts. This should be considered when using total counts to assess population sizes in the future.
Ladattava julkaisu This is an electronic reprint of the original article. |  |
