Niche-tracking migrants and niche-switching residents: evolution of climatic niches in New World warblers (Parulidae)

Abstract

Differences in life-history traits between tropical and temperate lineages are often attributed to differences in their climatic niche dynamics. For example, the more frequent appearance of migratory behaviour in temperate-breeding species than in species originally breeding in the tropics is believed to have resulted partly from tropical climatic stability and niche conservatism constraining tropical species from shifting their ranges. However, little is known about the patterns and processes underlying climatic niche evolution in migrant and resident animals. We evaluated the evolution of overlap in climatic niches between seasons and its relationship to migratory behaviour in the Parulidae, a family of New World passerine birds. We used ordination methods to measure seasonal niche overlap and niche breadth of 54 resident and 49 migrant species and used phylogenetic comparative methods to assess patterns of climatic niche evolution. We found that despite travelling thousands of kilometres, migrants tracked climatic conditions across the year to a greater extent than tropical residents. Migrant species had wider niches than resident species, although residents as a group occupied a wider climatic space and niches of migrants and residents overlapped extensively. Neither breeding latitude nor migratory distance explained variation among species in climatic niche overlap between seasons. Our findings support the notion that tropical species have narrower niches than temperate-breeders, but does not necessarily constrain their ability to shift or expand their geographical ranges and become migratory. Overall, the tropics may have been historically less likely to experience the suite of components that generate strong selection pressures for the evolution of migratory behaviour.

Reconstructing the geographic and climatic origins of long‐distance bird migrations

“…Here we studied an almost unexplored area: the biogeographic and climatic context of the evolutionary emergence of long-distance bird migration worldwide (see Gomez et al, 2016).…”

“…Gomez, Tenorio, Montoya, & Cadena, 2016;Laube, Graham, & Boehning-Gaese, 2015;Zurell, Gallien, Graham, & Zimmermann, 2018). Gomez, Tenorio, Montoya, & Cadena, 2016;Laube, Graham, & Boehning-Gaese, 2015;Zurell, Gallien, Graham, & Zimmermann, 2018).…”

Annual temperature variation influences the vulnerability of montane bird communities to land‐use change

“…The data used to calculate the thermal niche overlap scores were originally collected by the authors of this study in the same study regions, thereby ensuring that metrics associated with thermal sensitivity and sensitivity to forest conversion are regionally consistent. Thermal niche overlap metrics are a strong indicator of a species' sensitivity to the thermal environment (Gomez et al 2016), with higher thermal niche overlaps indicative of greater thermal sensitivity. For each species -and separately in the west and east -we calculated the thermal niche occupied in summer (breeding) and winter (non-breeding), defining the thermal niche as the area of the 95% minimum convex polygon of minimum and maximum daily temperatures associated with each bird observation (for details, see Srinivasan et al 2018).…”

Seasonal niche‐tracking behaviour of two partially migratory passerines

“…For instance, not all individuals track the same resources under all circumstances and an environmental trait that is closely tracked in one area may be ignored in another (Gomez et al . ). This is the case for Blackcaps, which change their food preferences between the seasons from a diet of insects during the breeding season to a predominantly frugivorous diet during winter (Jordano & Herrera ).…”

“…As a result, birds may exhibit either niche‐tracking or niche‐switching depending on their degree of migratory behaviour (Gomez et al . ). However, early approaches to detecting niche‐tracking behaviour were probably flawed by methodological difficulties, including those associated with multi‐species approaches (Peterson , Laube et al .…”