caa a22 4500 60616491X CHVBK 20210128100651.0 cr unu---uuuuu 210128e20151001xx s 000 0 eng 10.1007/s10144-015-0502-5 doi (NATIONALLICENCE)springer-10.1007/s10144-015-0502-5 Large and irregular population fluctuations in migratory Pacific ( Calidris alpina pacifica ) and Atlantic ( C. a. hudsonica ) dunlins are driven by density-dependence and climatic factors [Elektronische Daten] [Cailin Xu, Jennifer Barrett, David Lank, Ronald Ydenberg] Understanding the forces driving population dynamics is critical for species conservation and population management. For migratory birds, factors that regulate population abundance could come from effects experienced on breeding areas, wintering grounds, or during migration. We compiled survey data for Pacific and Atlantic subspecies of dunlins (Calidris alpina pacifica and C. a. hudsonica) from range-wide Christmas bird counts (1975-2010), and investigated the influences on this population index of density-dependence, falcon numbers, a set of seasonal environmental conditions during breeding, migration and non-breeding periods, and large-scale meteorological measures. For both sub-species, numbers fluctuated irregularly, varying threefold over the survey period, with no long-term upward or downward trend. Based on Royama's general model framework, the change in numbers between successive years for both sub-species was negatively affected by the total count in the previous year (i.e., negative density-dependence) and by the eastward component of storm movement during fall migration, with slower motion associated with higher population growth. The remaining environmental factors differed between the sub-species (snowmelt date on the Pacific, temperature on the Atlantic) or acted in opposite directions (soil moisture). The directional effects of each of these factors are consistent with the biology of dunlin, and together they explain 67.4 (72.9%) of the variation in the rate of change of Pacific (Atlantic) dunlin annual counts. Falcon numbers were not predictive, despite a tenfold increase in abundance, suggesting compensatory mortality. This study highlights directions for future studies, and provides a model for the analysis of other migratory species. The Society of Population Ecology and Springer Japan, 2015 Annual cycle nationallicence Christmas bird counts nationallicence Large scale analysis nationallicence Migratory shorebirds nationallicence Population dynamics nationallicence Seasonal environmental conditions nationallicence Xu Cailin Centre for Wildlife Ecology, Simon Fraser University, 8888 University Drive, V5A 1S6, Burnaby, BC, Canada aut Barrett Jennifer Centre for Wildlife Ecology, Simon Fraser University, 8888 University Drive, V5A 1S6, Burnaby, BC, Canada aut Lank David Centre for Wildlife Ecology, Simon Fraser University, 8888 University Drive, V5A 1S6, Burnaby, BC, Canada aut Ydenberg Ronald Centre for Wildlife Ecology, Simon Fraser University, 8888 University Drive, V5A 1S6, Burnaby, BC, Canada aut Population Ecology Springer Japan 57/4(2015-10-01), 551-567 1438-3896 57:4<551 2015 57 10144 https://doi.org/10.1007/s10144-015-0502-5 text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10144-015-0502-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Xu Cailin Centre for Wildlife Ecology, Simon Fraser University, 8888 University Drive, V5A 1S6, Burnaby, BC, Canada aut NATIONALLICENCE 700 1- Barrett Jennifer Centre for Wildlife Ecology, Simon Fraser University, 8888 University Drive, V5A 1S6, Burnaby, BC, Canada aut NATIONALLICENCE 700 1- Lank David Centre for Wildlife Ecology, Simon Fraser University, 8888 University Drive, V5A 1S6, Burnaby, BC, Canada aut NATIONALLICENCE 700 1- Ydenberg Ronald Centre for Wildlife Ecology, Simon Fraser University, 8888 University Drive, V5A 1S6, Burnaby, BC, Canada aut NATIONALLICENCE 773 0- Population Ecology Springer Japan 57/4(2015-10-01), 551-567 1438-3896 57:4<551 2015 57 10144