title: Spatio-temporal variation of biotic factors underpins contemporary range dynamics of congeners.
abstract: Species' ranges are complex often exhibiting multidirectional shifts over space and time. Despite the strong fingerprint of recent historical climate change on species' distributions, biotic factors such as loss of vegetative habitat and the presence of potential competitors constitute important yet often overlooked drivers of range dynamics. Furthermore, short-term changes in environmental conditions can influence the underlying processes of local extinction and local colonization that drive range shifts, yet are rarely considered at broad scales. We used dynamic state-space occupancy models to test multiple hypotheses of the relative importance of major drivers of range shifts of Golden-winged Warblers (Vermivora chrysoptera) and Blue-winged Warblers (V. cyanoptera) between 1983 and 2012 across North America: warming temperatures; habitat changes; and occurrence of congeneric species, used here as proxy for biotic interactions. Dynamic occupancies for both species were most influenced by spatial relative to temporal variation in temperature and habitat. However, temporal variation in temperature anomalies and biotic interactions remained important. The two biotic factors considered, habitat change and biotic interactions, had the largest relative effect on estimated extinction rates followed by abiotic temperature anomalies. For the Golden-winged Warbler, the predicted presence of the Blue-winged Warbler, a hypothesized competitor, most influenced extinction probabilities, contributing to evidence supporting its role in site-level species replacement. Given the overall importance of biotic factors on range-wide dynamic occupancies, their consideration alongside abiotic factors should not be overlooked. Our results suggest that warming compounds the negative effect of habitat loss emphasizing species' need for habitat to adapt to a changing climate. Notably, even closely related species exhibited individual responses to abiotic and biotic factors considered.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord St., Toronto, ON, M5S 3G5, Canada.
authors.forename: Ilona
authors.identifier: http://orcid.org/0000-0001-9504-4484
authors.initials: I
authors.lastname: Naujokaitis-Lewis
authors.affiliation: Department of Ecology and Evolutionary Biology, University of Toronto, 25 Harbord St., Toronto, ON, M5S 3G5, Canada.
authors.forename: Marie-Josée
authors.initials: MJ
authors.lastname: Fortin
mesh_terms: D063147:Animal Distribution; D000818:Animals; D044822:Biodiversity; D002170:Canada; D057231:Climate Change; D017753:Ecosystem; D008954:Models, Biological; D011157:Population Dynamics; D020308:Songbirds / Q000502:physiology*; D013696:Temperature; D014481:United States
keywords: Vermivora species; climate change; demographic processes; dynamic occupancy; habitat loss; range shift; spatio-temporal variation; species distribution models