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Ecological and life‐history traits explain recent boundary shifts in elevation and latitude of western N orth A merican songbirds
Author(s) -
Auer Sonya K.,
King David I.
Publication year - 2014
Publication title -
global ecology and biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.164
H-Index - 152
eISSN - 1466-8238
pISSN - 1466-822X
DOI - 10.1111/geb.12174
Subject(s) - latitude , ecology , interspecific competition , biological dispersal , range (aeronautics) , biology , population , songbird , geography , demography , materials science , geodesy , sociology , composite material
Aim Species are expected to move uphill or poleward in response to climate change, yet their distributions show idiosyncratic responses; many species are moving in the predicted direction, but others are not shifting at all or are shifting downhill or towards the equator. Fundamental questions remain about the causes of interspecific variation in range responses and whether shifts along elevational and latitudinal gradients are correlated. We examined whether shifts in northern‐latitude and upper‐elevation boundaries of western N orth A merican songbirds over a 35‐year period were correlated and whether species ecological and life‐history traits explained interspecific variation in observed shifts. Location N orth A merica. Methods We used data from the N orth A merican B reeding B ird Survey to determine shifts in northern‐latitude and upper‐elevation boundaries of 40 N orth A merican songbird species between two time periods, 1977–81 and 2006–11. We used an analysis of covariance approach that controlled for species population trends and changes in survey effort to test whether: (1) songbirds shifted in elevation, latitude or both; (2) shifts in elevation and latitude were correlated; and (3) responses could be explained by species‐level traits including life history, ecological generalization and dispersal capability. Results The majority of species shifted uphill and poleward during this period, but there was no correlation between the distances that species range boundaries shifted in elevation and latitude. Species with smaller clutch sizes and narrower diet breadths exhibited greater northward shifts, while species with larger clutch sizes and narrower diet breadths exhibited greater uphill shifts. Main conclusions Shifts in latitude and elevation were not correlated. However, a common set of species‐level traits explained differential responses among species to climate change. Consideration of shifts in both elevation and latitude is needed to understand the full extent to which species are tracking changing climates.